HGCAL CE-H HL-LHC Upgrade for CMS at CERN Kaushal Patel

The existing endcap ECAL and HCAL calorimeters are anticipated to undergo substantial radiation damage by the conclusion of Run-3, leading to a deterioration in their optimal physics performance. Consequently, a replacement for the current ECAL and HCAL endcap is planned, featuring a more resilient detector known as the High Granularity Calorimeter (HGCAL) to withstand the effects of radiation and ensure sustained high-performance capabilities. Utilizing fast plastic scintillator readouts with Enhanced Specular Reflector (ESR) coupled with Silicon Photomultipliers (SiPMs) is done to meet the demands of the HL-LHC's higher particle collision rates, which present significant challenges in radiation tolerance and event pileup for detectors. This research work involving physics and engineering was conducted at NICADD, recognized as the leading university-based accelerator physics group in Illinois. The innovative detector technology developed by our HGCAL group, along with international collaborations, has the potential to significantly impact particle physics. Once operational, it could lead to groundbreaking discoveries, redefining our understanding of the universe and making substantial contributions to the field.

www.linkedin.com/in/kaushalpatel28ee

1. High-Granularity Calorimeter Upgrade for CMS HL-LHC
Kaushal Patel
Northern Illinois Center for Accelerator and Detector Development
Updated - 6/4/2024
August 6
th
, 2021
[email protected]

2. Kaushal Patel (NIU) 1
•Large Hadron Collider or the LHC is the world’s largest and most powerful particle
accelerator and collider built which is operated by European Organization for Nuclear
Research (CERN).
•The LHC is a 27 km long accelerator ring, located ~ 100 m underground at the border
of Switzerland and France.
• LHC operates in three collision modes:
•Different collision modes serve different purposes for High energy Physics (HEP)
experiment.
•The source of protons in the LHC ring is the hydrogen gas. The protons are created by
stripping electrons from the hydrogen gas source.
•Accelerating this protons in the LHC requires very high energy, a series of accelerating
units
•The performance of each unit is optimized for a particular energy range; therefore,
protons will pass through various stages, as we will see in the next slide.
Aerial view of LHC with four collision points with detectors CMS, ATLAS, ALICE and LHCb
CMS and ATLAS are two main detectors for HEP
✓(a) proton-proton collision
✓(b) lead-lead
✓(c) proton-lead collision.

3. Kaushal Patel (NIU) 2
➢Focus and Bunch: Protons are first gathered and organized into tight bunches within a radiofrequency quadrupole
(RFQ).
➢Initial Acceleration: These bunches are then injected into a linear accelerator called LINAC2, where they receive an
initial boost to 50 MeV
➢Synchrotron Accelerators: The proton beam next enters a sequence of synchrotron accelerators,
•PSB (Proton Synchrotron Booster):Accelerates protons to 1.4 GeV.
•PS (Proton Synchrotron):Further accelerates protons to 26 GeV.
•SPS (Super Proton Synchrotron):Provides a final boost to 450 GeV before injecting the beam into the LHC ring.
•These synchrotron accelerators also refine the beam by reducing its transverse size and enhancing its brightness.
➢ Finally, LHC ring accelerates the protons reach their peak energy of 6.5 TeV.
•Protons circulate within the ring in tightly packed bunches,each containing approximately 1.15 x 10
11
protons.
•Bunches collide every 25 ns,generating high-energy interactions.
•While the LHC can accommodate 3560 bunches,only 2808 are actively filled.
•This intentional gap provides:
1.Time for fresh proton bunch injection to maintain collision rates.
2.A safety window for controlled beam dumping in case of emergencies.

4. Kaushal Patel (NIU) 3
Focusing QuadrupoleDe-focusing Quadrupole
FODO lattice
Cross section superconducting
quadrupole magnet
•Dipoles (Bending Magnets): Primarily used to bend the beam, guiding charged
particles along a curved path.
•To achieve stable vertical motion and maintain beam
focus in both planes, a combination of focusing (QF)
and defocusing (QD) quadrupoles is used.
•Effect: Provides horizontal and vertical focusing,
constraining the beam transversely.
•Betatron oscillations exist in both horizontal and
vertical planes.
Magnets can be classified based on their geometry or their effect on the beam. Additionally, charged particles are
accelerated by a longitudinal electric field that must oscillate in sync with the particles' revolution frequency.
Hill’s Equation

5. ➢Instantaneous luminosity quantifies the density of particles within a specific volume, such as the proton beam in the LHC. Increased luminosity indicates a higher probability
of particle collisions, leading to the desired interactions. This heightened luminosity can be accomplished by either increasing the number of particles in the beam or by
enhancing the beam's focus contributing to higher event rate:
➢The total number of events generated per second during the operational time of the collider is calculated by integrating equation
Kaushal Patel (NIU) 4
Instantaneous luminosity
Cross-sectionEvent rate per second
Instantaneous luminosity is expressed in terms of ��
−2
??????
−1
Integrated luminosity, total number of events during a period of data taking
Arbitrary starting pointTime period of interest
(1)
(2)

6. ➢The instantaneous luminosity (L) is determined by a combination of various accelerator parameters, as expressed in this formula
➢LHC collides beams at of protons at the instantaneous luminosity of 2 ?????? 10
34
��
−2
??????
−1
. The complex magnets of LHC are to be upgraded for HL – LHC, resulting in increased instantaneous
luminosity as direct consequence of equation (3) and (4) by reducing the �
∗
and crossing angle ??????
� .
➢At the Large Hadron Collider (LHC), numerous proton-proton (p-p) collisions take place. Majority of these interactions are categorized as soft, indicating that there is minimal momentum
transfer, resulting in the creation of particles with relatively low energy. However, a select few collisions are considered hard interactions, involving substantial momentum transfer. These
hard interactions are particularly intriguing because they have the potential to generate massive SM or BSM particles, making them the focus of scientific interest.

Kaushal Patel (NIU) 5
•??????
??????− represents the total number of particles in a bunch
•�
??????− number of bunches circulating in the LHC ring
•�
�????????????− frequency of the bunch revolution
•�
�− Lorentz boost factor
•Ꞓ
�− normalized transverse emittance
•�
∗
− beta function at collision point
•F − Geometric luminosity reduction factor
•Ꞓ
� �
∗
− Beam spot size at IP
•??????
� −crossing angle
•??????
z−root mean sqaurerms longitudinal size of the bunch
•??????
��−rms size of the buch in the tranverse direction

(3) (4)

7. ➢Soft particles are called pileup interactions The pileup will cause many challenges; we will explore the various issues that arise due to pileup.
➢The number of proton-proton interactions during a bunch crossing is determined by the instantaneous luminosity.By utilizing the total proton-proton inelastic cross-section ??????
??????�??????�
????????????
, ??????
??????��� and
the time interval between bunch crossing ΔT,we can calculate the average pileup (µ) using equation
Kaushal Patel (NIU) 6
•By substituting the corresponding values for LHC, i.e , ??????
??????��� = 2 ?????? 10
34
��
−2
, ΔT = 25 ns and ??????
??????�??????�
????????????
= 80 mb at TEV center of mass energy we obtain average pile of 40 as we can see from the
figure below it is very close to the 2018 LHC operation where left figure shows the peak instantaneous luminosity recorded by the CMS during different years of operation, and corresponding
pileup distribution is shown on the right. Pileup events will increase for HL-LHC and design values will be exceeded. The pileup will cause many challenges; we will explore the various issues
that arise due to pileup in this research presentation.

8. Kaushal Patel (NIU) 7
A simulated view of event display of all the p-p interaction vertices (yellow points)
during HL-LHC run. Each green line correspond to soft particles coming out of
bunch-crossing. 140-200 collisions per bunch crossing >> 3-4x larger than in run 2.
•The Phase-2 enhancement of the LHC necessitates the implementation of a detector with
enhanced radiation tolerance and the capability to effectively mitigate pileup challenges, which
poses a formidable challenge for the existing CMS detector. To address these conditions, the
CMS collaboration is strategically planning a comprehensive upgrade for all components of its
detector system. This upgrade encompasses improvements to the tracker, endcap calorimeters,
muon system, trigger, and data acquisition (DAQ) systems. The overarching goal is to ensure
and sustain optimal physics performance throughout the operation of the CMS detector during
the High-Luminosity LHC (HL-LHC) era.
•This research presentation will be focusing on particularly on the work for upgrading the
current Compact Muon Solenoid (CMS) Endcap calorimeters to High-Granularity Calorimeters
(HGCAL) with work focusing on the CE-H detector section for HL-LHC. Research involving
physics and engineering was done at Northern Illinois Center for Accelerator and Detector
Development (NICADD).
•DUNE Research work will be presented at the end of this presentation.

9. •By colliding protons with unprecedented energy, we aim to
recreate the primordial conditions that prevailed in the aftermath
of the Big Bang, unlocking the secrets of the universe's birth and
unraveling the fundamental mysteries of its earliest moments.
•By recreating these primordial conditions, we create a window
into the past, providing a glimpse into the fiery genesis of our
universe. It is a testament to human ingenuity, a technological
marvel that enables us to stand at the threshold of creation itself,
exploring the fundamental forces and particles that shape the
cosmos.
•Particle physics explores the fundamental constituents of matter
and the forces that govern their interactions.
Kaushal Patel (NIU) 8
Kaushal Patel HGCAL, NICADD,2021

10. Kaushal Patel (NIU) 9
•The discovery of the Higgs boson in 2012 was a landmark achievement for the Large Hadron Collider (LHC), fulfilling one of its
primary objectives. This discovery is considered one of the most significant in particle physics over the past fifty years, as it
confirmed the existence of the final component of the Standard Model of Particle Physics. Despite the Standard Model's
impressive predictive power, there is compelling evidence that it is incomplete. For instance, it does not account for dark matter,
nor does it explain why the mass of the Higgs particle is so low. With the advent of the HL-LHC the scientific community is now
focused on studying the detailed properties of the Higgs boson and its interactions with other known particles. The goal is to
identify any deviations from the Standard Model's predictions, which could reveal new physical phenomena beyond our current
understanding.
•The High-Luminosity LHC (HL-LHC) could provide key insights into several major questions in physics. It may help detect the
graviton, potentially validate string theory, reveal the nature of dark matter particles, and address unresolved cosmic mysteries,
offering new understanding of the universe.
scicomlab
scicomlab
scicomlab

11. Kaushal Patel (NIU) 10

12. Kaushal Patel (NIU) 11
Splash Test
Splash Test

13. Kaushal Patel (NIU) 12
➢The CMS experiment has a dual purpose, primarily focused on unraveling the mysteries
of electroweak symmetry breaking while also delving into Beyond Standard Model (BSM)
physics. The latter involves direct searches for new particles within the GeV to TeV mass
range, as predicted by innovative theories like Supersymmetry (SUSY).
➢To comprehensively address this broad spectrum of physics goals, the CMS detector has
specific requirements to:
•Achieve excellent muon identification and provide precise muon momentum resolution,
especially for muons with very high momenta, reaching approximately (TeV/c).
•Excellent energy measurement of �
±
/ �.
•Exceptional tracking of charged particles to facilitate the identification of key events,
including those involving tau leptons and jets originating from b quarks.
•Ensure hermetic coverage to enable precise estimation of missing transverse energy
??????
??????
�??????��
.
The CMS is built in an onion-like structure where different sub-detectors are placed in
concentric cylinders around the collision points.

14. Kaushal Patel (NIU) 13
Current Endcap
The value of |B| (left) and the field lines (right) predicted on a
longitudinal section of the CMS detector for the underground
model, with a central magnetic flux density of 3.8 T. Each field
line represents a magnetic flux increment of 6 Wb.

15. •The existing endcap ECAL and HCAL calorimeters are anticipated to undergo substantial
radiation damage by the conclusion of Run-3, leading to a deterioration in their optimal physics
performance. Consequently, a replacement for the current ECAL and HCAL endcap is planned,
featuring a more resilient detector known as the High Granularity Calorimeter (HGCAL) to
withstand the effects of radiation and ensure sustained high-performance capabilities.
•In this proposed configuration, the EE and HE components are substituted with a highly granular
sampling calorimeter utilizing silicon and scintillator + SiPM technologies. Leveraging the proven
robust performance of silicon-based detectors, as evidenced by their resilience in environments
with substantial radiation exposure, this design strategically employs silicon sensors in areas
characterized by high radiation levels for the bulk of the HGCAL detector.
•In the relatively low radiation region, scintillator tiles directly readout by Silicon Photomultipliers
(SiPM’s) are used as the active material.
•Operating within an intense radiation environment characterized by high pileup conditions, the
HGCAL is specifically engineered for 5D calorimetry. This entails precise measurements in three
positions (x, y, z), along with energy and time measurements. Consequently, the HGCAL is
proficient in generating detailed images of shower development, transforming it into an imaging
calorimeter ideally suited for particle flow reconstruction.
•HGCAL is intended to reliably identify and measure energy of jets, photons, electrons, taus, and
MET in a high-pileup environment until the end of the HL-LHC run period.
•Operating Temperature for whole HGCAL will be -30° C for minimizing noise in silicon sensors
and SiPM.
Kaushal Patel (NIU) 14
The HGCAL is a sampling calorimeter with unprecedented
longitudinal and transverse granularity.

16. Kaushal Patel (NIU) 15
Longitudinal schematic view of the HGCAL detector
Mixed layer in CE-H, Silicon located at high η and Scintillator located at low η

17. Kaushal Patel (NIU) 16
Typical jet:
~62% charged particles (mainly hadrons)
~27% photons
~10% neutral hadrons
~1% neutrinos
CMS Particle Flow Paradigm
•Precision Reconstruction: Accurately identify and reconstruct every particle within a jet.
•Prioritize Granularity: Focus on detailed spatial resolution in energy measurements to improve particle
separation and reconstruction.
•5D Imaging Capability: Utilize detectors capable of producing 5D images of particle showers for better
component separation. (X,Y,Z) + T + E.
•Improved Jet Energy Resolution: PF algorithms enhance the overall resolution of jet energy measurements,
currently being studied and optimization in progress, combine with the newest cutting-edge technology in the
detector it will give superior jet energy resolution and particle reconstruction.
•PF is currently utilized in the CMS detector within a less demanding environment.
TICL: The Iterative Clustering

18. Kaushal Patel (NIU) 17
Simulated event of 140 events in CMS
•Energy containment in CE-E
•Molière radius 28mm
Data rate: 40 TB/sec

19. Kaushal Patel (NIU) 18
No timing cut applied
After removal of hits with |∆t| > 90 ps ≈3σ at 30ps
VBF (H → γγ) event with one photon and one
VBF jet appearing in the same quadrant
γ
VBF Jet
VBF Jet
γ

20. Kaushal Patel (NIU) 19
→
•Layer by layer development of showers. Photon and VBF jet
are visible in the layers of the electromagnetic part – CE-E.
VBF jet carries 720 GeV (pT = 118 GeV) along with a photon
with 175 GeV (pT = 22 GeV).
•Mean pileup of 200 interactions per bunch crossing

21. Kaushal Patel (NIU) 20
→
Two Pions surfacing in 15 layers of CE-H, become visible
in the layers of the hadronic part – CE-H

22. Kaushal Patel (NIU) 21
❖ Hexagonal modules based on Si sensors in CE-E makes use of geometry of CE-E and high-
radiation regions of CE-H.
•Si sensors come in three thicknesses: 120, 200, and 300m and vary in cell size 0.5 and
1.2cm
2
with radiation levels for optimal physics performance.
•200 cells of 1.2cm
2
300um & 200um thickness.
•450 cells of 0.5cm
2
120um active thickness.
•Thin sensors collect more charge at high fluence.
•Limited by power and cooling considerations.
•30,000 modules with 6M silicon channels covering 620m
2
area (8’’ hex wafers).
Sensor layer with cells of
different sizes marked on
the layer.

23. Kaushal Patel (NIU) 22
❖CE-H (Hadronic Endcap Calorimeter) - Hadronic Shower Detector
•The CE-H layers are built using cassettes, with silicon modules and scintillator tile-boards mounted on
a 6 mm thick copper cooling plate located only on the side facing the proton-proton collision point.
These cassettes are combined to form a complete CE-H layer. The first 12 layers use 35 mm thick
stainless-steel absorbers, while the last 12 layers use 68 mm thick stainless-steel absorbers.
•To assemble a full CE-H endcap, 22 cassettes layers (8 silicon cassettes, 14 silicon/Scintillator
Cassettes) and absorber layers are stacked together.
•The overall depth of CE-H extends to approximately 157 cm, with a total depth equivalent to around
~ 8.5 ??????
??????�� .
❖CE-E (Electromagnetic Endcap Calorimeter) - Electromagnetic Shower Detector
•Each layer of the HGCAL is constructed from multiple 60-degree wedges, known as cassettes. In the
CE-E layers, each cassette contains silicon sensor modules mounted on both sides of a 6 mm thick
copper cooling plate with onboard electronics, shown in next slide. Six cassettes are combined to
form a complete CE-E layer. The supporting structure of each silicon sensor module, called the
baseplate, is made of CuW. A steel-clad lead absorber, about 4.9 mm thick, is placed between each
cassette in the CE-E layers. Thus, the CE-E has alternating layers of lead and Cu/CuW absorbers with
active silicon layers in between.
•28 CE-E layers (Double sided cassettes with 1 trigger layer per cassette)
•The depth of CE-E is approximately 34 cm, contributing to a total depth equivalent to around ~25 ??????
0
and ~1.3 ??????
??????��
Electromagnetic (CE-E) cassettes stack
Scintillator + SiPM
Silicon

24. Kaushal Patel (NIU) 23
•Schematic layout of a CE-E cassette, illustrating the arrangement of silicon modules and a potential
motherboard configuration. The dark green modules feature 120 µm thick sensors with 432 channels per
full-size module. The two progressively lighter green modules have sensors that are 200 µm and 300 µm
thick, each with 192 channels per full-size module. Motherboards are represented by rectangles. Full-size
modules have a width of 164 mm between the flat sides, while the motherboards are 94 mm wide.
Modules that are 50% and 80% of the full area are used to enhance coverage at the inner and outer
edges. The right side illustrates the fixation of the modules to the baseplate in a CE-E cassette, with a
cross-section view through the cassette's thickness. This view highlights the position where a specialized
screw-nut pair secures the corners of three adjacent modules and establishes the spacing between the
cooling plate and lead absorber layers.
Layout of the motherboards on a 60° cassette of the 8th layer of
CE-E. The black (red) numbers indicate the average bandwidth of
the motherboard output for DAQ data (trigger data) in GB/s. This
is based on pp collisions at the highest luminosity, corresponding
to an average of 200 interactions per bunch crossing.

25. Kaushal Patel (NIU) 24
•The sensor layout for both sides of the downstream-most CE-E cassette used in
thermal simulations is described as follows. Dark green sensors at the inner radius
represent high-density modules, each with 432 channels for a full hexagon, while
light green sensors denote low-density modules, each with 192 channels for a full
hexagon. The power dissipation values for each sensor type are factored into the
thermal calculations.
•The total heat load in this cassette is 780W
•3D model of the outer edge of a CE-E cassette, depicting silicon modules mounted
on both sides of the cooling plate, along with the stainless-steel clad lead covers
and absorbers
The routing of the two cooling tubesThe simulated temperature distribution
Two cooling loops are employed to match the 30-degree segmentation used in the CE-H

26. ❑What are Plastic Scintillators?
A special Kind of material medium in which if a charge particle enters, it basically absorbs
that energy of the charged particle and leads to the emission of light.
•Transparent plastic is easily cast, bent, cut, injection molded, extruded and polished.
•Possibility to have various shapes.
•Very fast response due to short decay time.
•Light yield is proportional to the deposited energy.
•Light mostly propagates by total internal reflection.
•The surface of the scintillator is delicate and prone to developing micro-cracks, which
can significantly reduce light transmission due to total internal reflection. Even
something as simple as fingerprints can cause these micro-cracks, highlighting the
need for careful handling.
Kaushal Patel (NIU) 25
❑How does the emission of light happen ?
When an external particle, like a beta particle, traverses the medium, it engages in
collisions with the molecules within the material. This interaction results in the
transfer of energy to the material, causing electrons within the valence band to
absorb this energy and transition to the conduction band. Subsequently, as these
electrons return to the valence band, they emit photons. Essentially, the objective is
to induce molecular excitation in the scintillator by introducing an external particle.

27. Kaushal Patel (NIU) 26
❖Plastic scintillators used in high-energy physics are typically binary or ternary
solutions of selected fluors dissolved in a plastic base containing aromatic rings.
The scintillation process involves the following steps:
•Primary Ionization: Incoming radiation interacts with the scintillator, causing
ionization and excitation of the molecules in the aromatic polymer base.
•De-excitation of the Base Polymer: The excited molecules in the base
polymer de-excite, producing scintillation photons with a wavelength around
300 nm. These photons are absorbed by the primary fluor.
•Energy Transfer to Primary Fluor: The energy transfer occurs over a very
short distance, where the primary fluor absorbs the 300 nm photons from the
base polymer.
•Emission by Primary Fluor: The primary fluor emits photons at a longer
wavelength, around 340 nm.
•Absorption by Secondary Fluor: These 340 nm photons are then absorbed by
a secondary fluor.
•Emission by Secondary Fluor: The secondary fluor emits photons in the
visible spectrum, typically around 400 nm.
•Detection by Silicon Photomultiplier: The visible photons are then detected
by SiPM.
Shift of the emission to higher wavelength

28. Kaushal Patel (NIU) 27
Prototype Tile, 5mm
•Wavelength shifting fibers embedded in plastic scintillator.
•Material absorbs blue light and emits green light in all directions
(isotropically).Notably,a significant portion of the green light remains
trapped within the material due to total internal reflection as shown in
above examples.
•WLS have negative impact on timing and increase in cost driver
•Fiber test -bending test analysis, light leakage, loss measurement…
Surface treatment of tiles for HGCAL
•To protect loss of scintillation signal, light produced needs to be trapped and guided to SiPM.
•Traditional approach involves placing an optical fiber within a scintillator, coating with white
paint, using reflective film (only for top and sides) which captures and directs the light towards
a Silicon Photomultiplier (SiPM) while the surface of the tile is coated in white paint. Many
research/studies and test were done for prototypes for light yield response
•This methods are not suitable for large scale assembly and production of tiles, so let's introduce
a new approach with focus also on maximizing/optimizing LY (major parameters to overcome).
Top and sides using reflective film,
but not bottom
Kaushal Patel HGCAL, NICADD,2021 Kaushal Patel HGCAL, NICADD,2021

29. Kaushal Patel (NIU) 28
❖For HGCAL scintillator tiles are made from plastic with organic doping, and
are injection molded and Cast. Cast has higher cost, but twice as large LY.
❖Tiles will increase in size with increasing radial distance from the beam
pipe to match the geometry of the CMS endcap.
• 21 sizes - 23x23mm² to 55x55mm², trapezoidal shape
•Dimple geometry construction is chosen to guide light
directly to the surface mounted SiPM’s.
•Driven by cost, performance, and ease of assembly
considerations.
•Dimple design would allow uniformity of response of
scintillation light for tiles.
•Individually wrapped in reflector foil.
•High light yield where the radiation damage is highest.
•Light yield is proportional to
WLS fiber and reflective paint not needed anymore
Three 3 × 3 cm
2
scintillator tiles mounted on a
PCB that holds one SiPM per tile. The left two
scintillators are unwrapped to show the SiPM
within the small dome at the center of the tile,
while right-most tile is wrapped with reflective
foil.
Layout of wafers and tiles in a layer where both are present: the 22nd layer of CE-H

30. •The Enhanced Specular Reflector (ESR) is an optical enhancement
film with a mirror-like quality, exhibiting an exceptional reflectivity
of over 98% throughout the entire visible spectrum.
•Film is made of multi-layer polymer technology, its nonmetallic.
•65 Micron Thin.
•ESR Films are currently cut with Cricuit machine by using a file
from the CAD.
•ESR is wrapped 360 degrees around the scintillator tile to guide
the light to the SiPM.
•3M ESR technology is also utilized in cell phone display technology
to enhance display brightness while minimizing battery
consumption. This is achieved by optimizing the efficiency of the
backlight.
•Tyvek wrapped tiles were also used to study the LY behavior,
however after studying it is found that ESR film is better as it gives
the greatest increase in LY.
Step 2 (CAD drawing) Step 3 (Cutting of ESR)Step 4 (ESR film cutting finish)
Step 5 (CNC wrapping machine used) Step 6 (Wrapped tiles with ESR)
Kaushal Patel (NIU) 29
Step 1 (Injection molded tiles)
Kaushal Patel HGCAL, NICADD,2021
Kaushal Patel HGCAL, NICADD,2021
Kaushal Patel HGCAL, NICADD,2021 Kaushal Patel HGCAL, NICADD,2021
Kaushal Patel HGCAL, NICADD.2021
Kaushal Patel HGCAL, NICADD,2021

31. Kaushal Patel (NIU) 30
•The number of scintillator tiles needed for HGCAL is enormous (240k). Every
single tile needs to be individually wrapped with ESR to make them light tight,
because of this emphasis are put on the CNC wrapping machine.
•Half of the tiles will be wrapped at NIU, and another half would be wrapped at
Deutsches Elektronen-Synchrotron (DESY research centre) located in Germany.
•A Computer Numerical Control (CNC) machine used for wrapping the ESR
around tiles.
•Development of G-code is specifically tailored for the tile-wrapping process and
manages various aspects, including position, coordination, location, speed, and
more.
•Air-pressure induced wrapping operations.
•3-4 tiles per minute aimed for wrapping.
G - code snippet
UI of the control panel showcasing
the X, Y, Z coordinates
Kaushal Patel HGCAL, NICADD,2021

32. Kaushal Patel (NIU) 31
ESR placement End Effector Indication of which side the scintillator tile
should face when wrapping, since they are
trapezoidal in shape, not following the
placement currently would result in damage to
the actuators and the tile and ESR.
ESR picked using suction air from the
End Effector.
֍ Custom build CNC machine for CMS HGCAL - Scintillator ESR wrapped tile production ֍
•Control panel wiring and initial programming of the CNC controls has been done at NIU.
•Studies of wrapping machine and its behavior have been done, next step is optimizing
the movements and minimizing down time in X, Y, Z direction such that we are meeting
the production goal.
•3 Servo motors used for X, Y, Z direction controls.
24 VDC, servo motor,
z-direction control
Kaushal Patel HGCAL, NICADD,2021Kaushal Patel HGCAL, NICADD,2021Kaushal Patel HGCAL, NICADD,2021 Kaushal Patel HGCAL, NICADD,2021
Kaushal Patel HGCAL, NICADD,2021

33. Kaushal Patel (NIU) 32
ESR placement done, suction air
underneath ESR to keep it in place.
Base plate Actuator arms and scintillator tile
picked by End Effector
Tile placement on base plate done in the center
•Actuators are label to identify which arms should move when and in which order,
based on wrapping studies done for LY and due to shape of the tile.
•Monitoring CNC machine operation for unusual vibration or sounds, and checking
the clearance path to ensure smooth operation is a crucial step when operating
the CNC machine.
•Implementation of translational movements to enhance reproducibility
Scintillator tile placement
for picking up the tile
Example of clearance issue
Kaushal Patel HGCAL, NICADD,2021Kaushal Patel HGCAL, NICADD,2021Kaushal Patel HGCAL, NICADD,2021 Kaushal Patel HGCAL, NICADD,2021
Kaushal Patel HGCAL, NICADD,2021
Kaushal Patel HGCAL, NICADD,2021

34. Kaushal Patel (NIU) 33
Scintillator tile picked by End Effector to
be dropped in the hole, a storage system
will be used to collect scintillator tiles that
are ESR wrapped.
Finished ESR wrapped Scintillator tile
Actuator arms holding down ESR film,
sticker placement is done by hand as of
right now, an automatic sticker machine
would be integrated to place the sticker
on the tile to remove human errors.
Scintillator tile placement done on top of ESR
and pushed by the End Effector inside a pocket
•Assembly and production quality will increase by using more modifications once testing/prototyping
stage is done and moving into the production phase.
•Gloves are required for ESR and scintillator tile as fingerprints has a big potential to impact the LY
response impacting the physics performance of the wrapped tile for particle detection process.
•Not shown: Safety interlocks and other sensors.
Kaushal Patel HGCAL, NICADD,2021 Kaushal Patel HGCAL, NICADD,2021Kaushal Patel HGCAL, NICADD,2021Kaushal Patel HGCAL, NICADD,2021
Kaushal Patel HGCAL, NICADD,2021

35. Kaushal Patel (NIU) 34
DESY - Automatic Wrapping station
Valve Control system
Ionizer, for overcoming the issue of ESR having static friction
Kaushal Patel HGCAL, NICADD,2021

36. Kaushal Patel (NIU) 35
This design for ESR is easier to wrap using CNC, but it
requires more ESR material, leading to increased costs.
Additionally, it is more affected by radiation levels due
to its larger surface area. Therefore, it was not chosen
to go forward with.
Construction of ESR film
Kaushal Patel HGCAL, NICADD,2021
Kaushal Patel HGCAL, NICADD,2021

37. •Silicon Photomultiplier (SiPM), is a new type of solid-state photo
detector that is sensitive enough to detect single photos.
•Made of tiny pixels (10-50 microns), each pixel acts like single
photon avalanche diode (SPAD). When a photon strikes an SPAD,
a photoelectron is generated.
•SiPM are insensitive to magnetic fields, small and compact.
•High Gain (10⁶) Comparable to that of photomultiplier tube
(PMT).
•Low Operating voltages at around (50-60V).
Kaushal Patel (NIU) 36
6mm × 6mm active area SiPM’s
2mm × 2mm active area SiPM’s
Kaushal Patel HGCAL, NICADD,2021

38. Kaushal Patel (NIU) 37
SiPM Characteristics vs photosensitive area
SiPM Characteristics vs pixel size
SiPM Characteristics vs operating voltage

39. Kaushal Patel (NIU) 38
An array of SPADs connected parallel and SiPM Signal Formation with
Schematic. The larger the pixel capacitance or the higher the reverse voltage
the, the higher the gain.
•Operating the Single-Photon Avalanche Diode (SPAD) above its breakdown voltage is commonly known as
Geiger-mode operation. This term is used because the SPAD consistently produces the same output signal,
regardless of whether it is exposed to one, two, or numerous photons simultaneously, resembling the behavior
of a Geiger-Müller counter. In this mode, the SPAD is binary, being either in an on or off state, with the on-state
remaining constant irrespective of whether the avalanche is initiated by one or a hundred photons.
•To address this limitation, multiple SPADs are organized in an array and connected in parallel.
•SiPMs gain is defined as charge (Q) of the pulse generated from one SPAD when it one photon hits the SPAD
divided by charger per electron (1.602 × 10
-19
)

Charge Q depends on the reverse voltage (??????
??????) and breakdown voltage (??????
�??????) with the equation
Quenching resistor used for stopping the electron avalanche.

40. Kaushal Patel (NIU) 39
Quenching resistor (Rq), thin
metallic strip resistor
SPAD Active area
Equivalent circuit of a SPAD with series quenching resistor and
external bias. Switch models the turn-on (photon absorption or
dark event) and turn off (quenching probabilities)
Breakdown, Quench
and Reset Cycle of a
SPAD Working in
Geiger Mode
When a microcell detects a photon, it triggers a Geiger
avalanche, generating a photocurrent. This causes a voltage
drop across the quenching resistor, reducing the bias across
the diode and preventing further avalanches. The recovery
time is the duration for the microcell to recharge. Importantly,
the Geiger avalanche is confined to the triggering microcell,
allowing other microcells to remain charged and ready for
photon detection.
Microscopic Image of SPAD and a quenching
resistor, each independently operating. Unit of both
will be referred to as a microcell/pixel.
??????
??????????????????
??????
??????????????????
Equivalent circuit of a SPAD
RQ must be large enough to ensure quenching.

41. Kaushal Patel (NIU) 40
Time to recharge a cell after a
breakdown depends mostly on
the cell size (via ??????
�????????????) and the
quenching resistor (�
�)
??????=??????
?????????????????????????????? ∙ �
�
RechargingDischarging
0.1
1
10
100
1000
10000
100000
48 50 52 54 56
Current, nA
Voltage, V
06/29/2021 IV for 6x6 SiPM test using LED
Reverse current breakdown
Method of Inverse logarithmic Derivative (ILD),
allows to characterize I(V) curves particularly
breakdown voltage
Kaushal Patel HGCAL, NICADD,2021

42. Kaushal Patel (NIU) 41
➢Dark count rate (DCR), even without any light pulses,
occurrence of signals can be observed. These signals are
caused by thermal electrons triggering an avalanche. DCR
is the main source of noise and varies with ambient
temperature
Dark Pulse
➢The quantity of the observed dark pulse is known as
the dark count, while the number of dark pules per
second is expressed as dark count rate, measured in
unit [CPS] counts per second.
Dark count rate of SiPM defined by
Hamamatsu, number of pulses generated
& exceed this threshold of 0.5 p.e. is
expressed as below
Dark count rate vs Ambient temp, with constant gain
Kaushal Patel HGCAL, NICADD,2021

43. Kaushal Patel (NIU) 42
Time Time
Pulse height Pulse height
1 p.e.
2 p.e.
2 p.e.
1 p.e.
3 p.e.
➢Instance of pulse of 2 or more p.e. registering, due to secondary
photons generated in the avalanche multiplication process of the
microcell. These photons are picked by neighboring microcells
(triggering them). This makes it a form of correlated noise
➢Crosstalk probability increases as reverse voltage is increased
➢During avalanche multiplication process , charge carries can be trapped by
silicon lattice defects and be released after some time. When released, they
are multiplied by the avalanche process along with photon-generated
carries, causing afterpulses a form of correlated noise to be observed.

44. Kaushal Patel (NIU) 43
67.2
67.4
67.6
67.8
68
68.2
68.4
68.6
68.8
69
69.2
61 61.5 62 62.5 63 63.5 64 64.5
C
urrent
,
n
A
Ambient Temperature
Dark Current vs Temp
➢The Dark Current is the cumulated charge originating from the Dark Count
Rate (DCR), Afterpulse (AP), and Crosstalk (CT), given by the equation:
Operated in dark state,
throughout the day without
any light, graph represents
operation of SiPM from
morning to afternoon.
Dark current will not be an
issue since HGCAL will be
operating at -30° C with
the help of CO
2 cooling
system

45. Kaushal Patel (NIU) 44
Fixed X-Y Stage
Dark Box
Dimensions of SiPM used for LY analysis
•In our laboratory set-up, we use the β-emitting isotope Sr
90
, which, along with its daughter nucleus
90
Y
provides a continuous electron energy spectrum up to ∼2.28 MeV to the scintillator tiles causing to the
emission of light. The tiles undergo precise scanning as the source moves along the X-direction in 2mm
increments, while the SiPM is operated in breakdown voltage.
•The β − decay products of the decay chain are the following:
•The objective is to investigate how tiles respond to various methods of ESR wrapping using the CNC
wrapping machine, but also the response of Cast vs Injection molded tiles. Another crucial goal is to ensure
uniform tile responses between DESY and NICADD. Given DESY's advanced equipment, it is imperative that
both institutions achieve comparable results. This consistency is vital since half of the tiles will undergo
testing and wrapping at NICADD, while the other half will be at DESY.
•The half-life of Sr⁹⁰ is 28.8 years, with a radiation dose of 20 mREM per hour.
•RADCON training is completed by all faculty and students involved in the research due to radiation
exposure.
•The Sr
90
consists of a tungsten body for efficient shielding and a source housing
Lab equipment
LabView for analysis from data
collected by SiPM, also used
for controlling the operation of
SiPM and Sr
90
Voltage
Electron beam direction
Signal
Z
Z
X
Y
SiPM parameters used for experiment
Opening underneath the Sr⁹⁰ casing, serving as
the gateway for electrons to be emitted along
the Z-axis.

46. Kaushal Patel (NIU) 45
X-Y stage with the Sr⁹⁰ Tile placement Scanning of tileSiPM view Beam Setup view
•Tiles are placed above SiPM, where they fit right under the concave shape of the tile.
•Currently Sr⁹⁰ able to scan one tile each time.
•Quality testing environment for testing multiple scintillator tiles with Sr⁹⁰ , picture shows multiple SiPM’s for
each tile that’s going to be placed in the appropriate section. We need to test multiple tiles as much as
possible to meet our production goal deadline as the amount of testing the tiles is enormous.
•Emphasis is placed on the meticulous handling and care of SiPM (pixels), ESR, and tiles. Factors such as
fingerprints, cracks, and scratches are recognized as potential influencers that can significantly impact the
light yield response.
•High Computation is done to extract all the information from the scintillator tile and SiPM to study LY by
using LabView and Excel.
Quality Control SetupMicroscope is used to see potential
microcracks on the tile impacting
the LY performance.
Kaushal Patel HGCAL, NICADD,2021 Kaushal Patel HGCAL, NICADD,2021 Kaushal Patel HGCAL, NICADD,2021 Kaushal Patel HGCAL, NICADD,2021
Kaushal Patel HGCAL, NICADD,2021
Kaushal Patel HGCAL, NICADD,2021
Kaushal Patel HGCAL, NICADD,2021

47. •The readings of tile scans will be evaluated based on their current nA response, which is read out by the SiPM. To understand how this works, we have to look at what is
actually happening inside the SiPM. To understand this, we have to first understand the depth to which light penetrates in the silicon of SiPM. In silicon, the penetration
depth of light varies with wavelength, short-wavelength light penetrates shallowly, generating carriers near the surface , while long – wavelength light generates carriers at
deeper positions. Avalanche multiplication occurs as carriers move through the high electric field near the PN junction. For SiPM, the ionization rate of electrons is high, so
that multiplication can be achieved efficiently when electrons are injected into the avalanche layer.
•Satisfactory gain characteristics can be obtained when long-wavelength light that reaches deeper than the avalanche layer is incident.
•Structure of SPAD determines whether short or long wavelength is multiplied efficiently.
Kaushal Patel (NIU) 46

48. 0
25
50
75
100
125
150
175
200
225
250
275
300
325
350
375
400
425
390 400 410 420 430 440 450 460
C
urrent
,
nA
Position of Sr⁹⁰ , mm
07/13/2021 NIU wrapped tiles #19, 2x2 SiPM on the board at 55.5-V
NIU_14/67.5 NIU_15/67.6 NIU_16/67.7 NIU_17/68.1 NIU_18/68.2 NIU_19/68.3
NIU_20/68.4 NIU_21/68.4 NIU_22/68.5 NIU_23/68.6 NIU_24/68.6 NIU_25/68.7
NIU_26/68.8 NIU_27/68.9 NIU_28/69 NIU_29/69.1
Kaushal Patel (NIU) 47
•Measurements of the light yield response in numerous tiles, resulting from
interactions with Sr⁹⁰ , were conducted using the NIU ESR-wrapped tiles.
•Continuous improvement has been achieved through ongoing R&D efforts
focused on ESR films and tiles, aiming to attain superior light yield and
consistent response uniformity.
•Average light yield distribution as a function of the Sr⁹⁰ position
•We have achieved results that are slightly better to those of DESY. However,
the outcome could have been even better. Unfortunately, the base plate of the
CNC machine was not leveled correctly during the wrapping process, causing a
discrepancy in the overall response and bringing down the average. As evident
on the right side of the graph, the level should ideally match that of the left
side, but due to the misalignment, it does not.
•This analysis offers an opportunity for improvement by evaluating the light
yield response from both physics and engineering perspectives.
NIU average response scan of scintillator tiles with Sr⁹⁰ along the diagonal

412-440 is 283.221
424-428 is 348.515
Kaushal Patel HGCAL, NICADD,2021

49. Kaushal Patel (NIU) 48
DESY average response scan of scintillator tiles with Sr⁹⁰ along the diagonal
412-440 is 254.258
424-428 is 320.446
•The average response of the DESY tiles is notably lower than that of the
NIU tiles, with significant variation in light yield responses among the DESY
tiles. This discrepancy is likely due to the DESY tiles not being tightly
wrapped, allowing light to escape and causing inconsistencies in their
performance compared to the more tightly wrapped NIU tiles.
The unwrapped tile was subjected to investigation, revealing the presence
of dust and cracks on the tiles, along with scratches on the ESR. These
imperfections collectively contributed to a reduction in the overall response
of the tile.
0
25
50
75
100
125
150
175
200
225
250
275
300
325
350
375
400
425
390 400 410 420 430 440 450 460
Position Sr⁹⁰ , mm
DESY_A/69.7 DESY_B/69.7 DESY_C/69.7 DESY_D/69.6 DESY_E/69.6 DESY_F/69.6
DESY_G/69.6 DESY_H/69.6 DESY_I/69.6 DESY_J/69.6 DESY_K/69.6 DESY_L/69.6
DESY_M/69.6 DESY_N/69.6 DESY_O/69.6 DESY_P/69.6
C
urrent
,
nA
06/22/2021 NIU molded DESY wrapped tiles #19; 2x2 SIPM on the board at 55.5-V
Kaushal Patel HGCAL, NICADD,2021 Kaushal Patel HGCAL, NICADD,2021
Kaushal Patel HGCAL, NICADD,2021

50. Kaushal Patel (NIU) 49
0
50
100
150
200
250
300
350
400
390 400 410 420 430 440 450 460
Current, nA
Position of Sr90, mm
06/24/2021 molded NIU wrapped tiles; 2x2 MPPC on the board
at 55.5-V
NIU-1/66.7 NIU_2/66.9 NIU_3/67.0 NIU_4/67.7
NIU-5/67.8 NIU-1A/67.9 NIU-2A/68.0
0
50
100
150
200
250
300
350
400
380 390 400 410 420 430 440 450 460 470
NIU-1/66.7 NIU_2/66.9

51. Kaushal Patel (NIU) 50
0
50
100
150
200
250
300
350
400
450
380 390 400 410 420 430 440 450 460 470
NIU Side 1/ 67.60
0
50
100
150
200
250
300
350
400
450
380 390 400 410 420 430 440 450 460 470
NIU Side 2/ 67.66
0
100
200
300
400
500
410 415 420 425 430 435 440 445
Shifted
Series1 Series2
0
100
200
300
400
500
410 415 420 425 430 435 440 445
Shifted
Series1 Series2
0
100
200
300
400
500
410 415 420 425 430 435 440 445
Shifted
Series1 Series2

52. Kaushal Patel (NIU) 51
0
50
100
150
200
250
300
350
400
450
380 390 400 410 420 430 440 450 460 470
NIU Side 3/ 67.77
0
100
200
300
400
500
410 415 420 425 430 435 440 445
Shifted
Series1 Series2
0
50
100
150
200
250
300
350
400
450
380 390 400 410 420 430 440 450 460 470
NIU Side 4/67.87
0
100
200
300
400
500
410 415 420 425 430 435 440 445
Shifted
Series1 Series2

53. Kaushal Patel (NIU) 52
•The scintillator tiles will be coupled with SiPM photo-detectors integrated on printed-
circuit-board (PCB), called tile-boards and SiPM will be soldered on the PCB.
•Each Tile would have its own photo sensor (SiPM), so that each tile acts as separate
channel.
•In the proposed detector design for the CMS endcaps, 36 tileboards are arranged
adjacent to each other, aligning with the circular structure of the endcaps around the
beam pipe. In the radial direction, perpendicular to the beam pipe, up to 5 tileboards
are positioned side by side to form a fundamental 10° detector unit. Scintillator and
silicon detector modules are integrated into common cassettes, with each cassette
covering a 60° segment. Six of these cassettes together form a ring around the beam
pipe in each layer.
•High-speed data transfer is a challenge.
Tileboard with scintillator tiles, SiPM’s, readout and calibration
electronics, and connectors for signals and power
Top view to a mixed 60° cassette of a detector layer

54. Kaushal Patel (NIU) 53
Low- intensity LED
SiPM
•Relative locations of the tileboards, the scintillator motherboard, and the cabling and wing PCBs which connect them.
•Scintillator Tileboards with SiPM, LED’s, ESR wrapped scintillator tile are mounted on a copper cooling plate 6mm thick with -30° C temp.
•Low-intensity LED next to SiPM used for calibration purpose next to each SiPM.
•Polyimide isolation foil (50µm) under tileboards, FR4 protective cover (200µm) on top.
•Digitized SiPM signals are transmitted from the HGCROC by electrical links, using Twinax cables, to a motherboard that is located at the
edge of the cassette.
•The Twinax cables have been shown to be radiation hard in fluences up to 1×10
16
n
eq/cm
2
.
•HGCROC, reads out the SiPM-on-tiles on the Tilemodule with up to 72 channels (1 or 2 per Tilemodule).
HGCROC (HGCAL Read Out Chip)
FR4 protective cover (200µm)
Kaushal Patel HGCAL, NICADD,2021
Kaushal Patel HGCAL, NICADD,2021

55. Kaushal Patel (NIU) 54
Block diagram of the on-detector electronics for the scintillator/SiPM detector layers

56. Kaushal Patel (NIU) 55
•NIU ESR wrapped tiles sent to DESY located in Germany for pick and place testing on board.
•Tilemodules will be produced and assembled at DESY (Hamburg, Germany) and Fermilab (USA).
•All final components will be attached to endcaps to be lowered into the CMS cavern in August
2027 (expected date).
Glue used for attaching tiles on board
Glue
NIU ESR Wrapped tested tiles
Placement done
Size scan

57. Kaushal Patel (NIU) 56
The projected total absorbed Rad dose in
HGCAL by the end of HL-LHC operation shown
as a two-dimensional map in the radial and
longitudinal coordinates, r and z.
Fluence, parameterized as a fluence of 1 MeV equivalent neutrons,
accumulated in HGCAL after an integrated luminosity of 3000 ��
−1 Dose of ionizing radiation accumulated in HGCAL after an integrated luminosity of 3000 ��
−1
•This conditions will cause severe radiation damage to the detectors and on-detector electronics. Constant irradiation to semiconductor devices will result in defects
and performance issues. Neutrons will cause displacement of silicon atoms from their positions in the lattice. This displacement leads to the formation of Frenkel pair
defects, involving interstitial and vacancy sites. It alters the electrical characteristics of the silicon, such as elevating leakage current and generating trap centers within
the lattice. These trap centers capture charge carriers, consequently reducing the efficiency of charge collection. Moreover, the damage to the semiconductor bulk
necessitates a high reverse bias voltage to attain full depletion width, leading to increased power consumption. Over time, as the damage accumulates, the silicon
sensors reach a point where they can no longer generate a desirable signal, resulting in the loss of optimal physics performance.
•Radiation-induced damage leads to the formation of absorption bands in the scintillator material, causing the generation of color centers. These color centers diminish
the transparency of the scintillator by attenuating the light passing through, resulting in a degradation of the total light output yield. Consequently, a significant portion
of the scintillating photons is absorbed, reducing the overall transparency of the scintillator. They will suffer from irreparable radiation damage.

58. Kaushal Patel (NIU) 57
The graphs display the spectra for alpha particle signals in EJ-200 polystyrene materials with double overdoping of the primary
dopant, both before and after receiving a total radiation dose of 0.38 Mrad at a rate of 300 rad/h.
Left Plot: This shows the material irradiated at room temperature. Right Plot: Shows the material irradiated and measured at low temperature.

59. Signal-to-noise ratio for a MIP, after an integrated luminosity of 3000 fb
-1
, shown
as a two-dimensional map in r and z. The region, at larger z and r, in which SiPM’s
mounted on scintillator tiles can provide S/N(MIP) > 5 after 3000 fb
-1
is outlined.
Kaushal Patel (NIU) 58
Multiple combinations will be used to combat RAD levels for optimal physics performance

➢Injection molded tiles with small SiPMs
➢Injection molded tiles with large SiPMs
➢Cast tiles with small SiPMs
➢Cast tiles with large SiPMs
➢Due to high radiation, cast tiles with large SiPMs will be used near silicon layers since it
gives largest S/N.
➢Long lifetime, at least needs to be operated till 2040 with much restriction when it comes
to repairing electronics inside the HGCAL.

60. Kaushal Patel (NIU) 59
Projected PE per 1 mm
2
of SiPM surface area,
signal amplitude for MIP in PE units
>50% scintillator signal after 3000fb
-1
Projected SiPM noise level in PE
Leakage current power signal after 3000fb
-1

61. Kaushal Patel (NIU) 60
(a) stacking of CE-E cassettes on the CE-E support
structure; (b) assembly of the CE-H absorber
structure; (c) insertion of CE-H cassettes and
dressing with electrical, optical and cooling services;
(d) rotation of the completed calorimeter to the
vertical orientation in preparation for installation.
Preliminary layout of the cooling and low-voltage
services on the surface of the HGCAL. A two-phase
CO₂ cooling system will deliver up to 140 kW of
cooling power per endcap, with a flow rate of 1 kg/s.
Layout of cooling loops on the HGCAL showing both the manifolds that
supply the cassette layers (two sets of supply and return lines every 30° )
and a preliminary routing of the vacuum jacketed coaxial lines over the
endcap suspension system brackets. The detection chamber will undergo
a constant flow of dry nitrogen during operational phases and dry air will
be introduced for safety precautions when the CMS is in an open state.
The empty bands are regions reserved for
mechanical supports of the absorber
structure and the thermal screen.

62. Kaushal Patel (NIU) 61
A Thermal Screen, comprising more than
120 individual panels equipped with electric
heating foils and internally flushed with dry
nitrogen gas, will safeguard the sensitive
detector electronics from humidity and
external forces, while also preventing
surface condensation on the outside.
CE-E support- created by
solid block of aluminum
via machining
CE-H support- stainless steel
designed to bear the weight of
Hadronic cassettes and stainless-
steel absorbers,
Sliding wedges: Stainless steel supports
engineered to support the entire weight
of the detector. The sliding feature
accommodates thermal contraction,
with one end of the wedges at -35°C and
the other at 18°C.
Weight of the single HGCAL endcap is estimated to
be 230 tonnes, a serious engineering challenge
when it comes to supporting the endcaps.
Brackets
~120kW power

63. Kaushal Patel (NIU) 62

64. Kaushal Patel (NIU) 63
Molds used for production of the
injection molded scintillator tiles

65. Kaushal Patel (NIU) 64
Timeline for LHC and HL-LHC operations along with physics runs and shutdown schedule

66. Kaushal Patel (NIU) 65
Supernova explosions Black holes Neutron stars
Some origin sources of Cosmic rays
Emission of light due to Cosmic rays
Kaushal Patel HGCAL, NICADD,2021

67. Kaushal Patel (NIU) 66
High-energy physics experiments at CERN contribute to technological advancements that enhance our daily
lives. The development of Silicon Photomultipliers (SiPMs) is propelled by multi-billion-dollar markets.
•A positron-emitting radiopharmaceutical called
Fluorodeoxyglucose (18F-FDG) is injected into the
patient.
•The annihilation of emitted positrons with electrons in
the tissue produces back-to-back photons, which are
detected by scintillating crystals. The light emitted by
these crystals can then be read out by SiPM’s.
•SiPM’s can be used for MRI, since they are not
affected by magnetic field.
Note: MPPC stands for Multi-Pixel
Photon Counter its just another
name for SiPM.
SiPM can detect tiny fluorescence
emissions from reagents.
SiPM’s can be utilized in LIDAR systems, providing several
advantages over current LIDAR technology.
-Higher Sensitivity
-Faster Response Time
-Compact and Lightweight
-High Gain
-Lower Operating Voltage
.
.
.

68. Kaushal Patel (NIU) 67
Advances in high energy physics technology
allowing to find unknown voids that might
exist in the structure of pyramids using
cosmic rays.

69. Kaushal Patel (NIU) 68
Deep Underground Neutrino Experiment: DUNE

70. Kaushal Patel (NIU) 69
DOM – Digital Optical Module
PMT’s
❖A model of neutrinos observation done in the galactic plane with IceCube data, the bars representing
the distribution of neutrinos origin coming from various astrophysical sources such as star formation or
supernova, they can also be formed when HEP accelerate along the magnetic lines (shown in blue) and
collide with other particles.
❖The IceCube Neutrino Observatory is a large-scale detector located at the South Pole. It is designed to
detect high-energy neutrinos.
❖Primary goals: Studying high-energy cosmic neutrinos to learn about their sources and the processes
that produce them, exploring the properties of neutrinos, such as their masses and oscillation behaviors
and much more.
❖Detects 100,000 neutrinos per year created in earths atmosphere, but only 100 neutrinos arrive from
cosmos per year. Machine learning filters out neutrinos we are not interested in so that we can focus on
neutrinos arriving from cosmos.
❖Whenever IceCube detects a cosmic neutrino, it automatically sends an alert to observatories
worldwide.
❖So how does IceCube benefit DUNE…using data from both detectors offers a more comprehensive view
of cosmic events, such as supernovae, and various physics phenomena, enriching our understanding of
the universe. This is especially valuable because our CMS detector provides limited information about
neutrinos.
❖Let's look at on next slide what is DUNE and how it works…
scicomlab

71. Kaushal Patel (NIU) 70
•DUNE is comprised of two neutrino detectors placed in the world’s most intense neutrino beam
traveling 800 miles underground through the earth.
•Two neutrino detectors starting at Fermilab (IL) → South Dakota
•A near detector at Fermilab is used to analyze the beam, while a far detector, located 1480 meters
underground at SURF in South Dakota, contains approximately 70,000 tons of liquid argon divided in 2
(Phase I) + 2 (Phase II) . This setup maximizes the potential of the wide-band neutrino beam.
•> 20 years foreseen life span
•5.8 degree vertical bend, to reach SURF
•Primary Focus goals- Why did matter win over matter, study of ?????? oscillations, CP violation, Search for
proton decay, Black Hole Formation, Supernova neutrinos burst detection sensitive to ??????
e component,
Solar neutrinos capability for ??????
T identification & BSM physics.
Muon neutrino beam - 1.2 MW beam
power - Upgradeable up to 2.4 M
International experiment for neutrino science and proton decay studies
60-120 GeV proton beam
on a graphite target

72. Kaushal Patel (NIU) 71
•DUNE utilizes advanced LArTPC technology for its highly sensitive and massive neutrino detector in FD.
•The FD includes sophisticated systems to detect both charge and light from ionization events within the
LArTPC.
•Argon scintillation light in LArTPCs is highly prolific, producing approximately 40,000 VUV photons per
MeV of deposited energy at a wavelength of 128 nm, which provides precise event timing crucial for
accurate particle interaction reconstruction.
•System requires a large detection area for photon collection, due to space limitations PMT’s have not
been chosen for their compact size.
•Charged particles passing through the detector ionize the
argon atoms.
•The resulting ionization electrons drift towards the anode
wall under an electric field over a timescale of milliseconds,
which provides 2D position information.
•The anode consists of layers of active wires forming a grid
structure.
High resolution 3D track reconstruction
Argon scintillation light (~ns) detected by photon SiPM
detectors , This provides additional information, and the
event start time (t
0​). Important for analysis such as
looking for proton decay, along with detailed tracking
and calorimetric information
Need Wavelength Shifter to Shift VUV to visible
Photosensors
Scintillation Light

73. Kaushal Patel (NIU) 72
A 10 kt DUNE FD SP module features alternating anode (A) and
cathode (C) planes, each 58.2 meters long and 12.0 meters
high. The FC encloses the drift regions between these planes.
The right-hand cathode plane illustrates the FC's foremost
portion in its folded, undeployed state.
Double-Shifted Light Guide Dip-Coated Light Guide
The photon detector design in DUNE utilizes light guides with wavelength shifters combined with photosensors. These light guides are long,
thin rectangular bars placed inside the cryostat. When photons hit the bar, they are wavelength-shifted and captured by the light guide.
The light then travels through total internal reflection towards the end of the bar, where photosensors are placed. These photosensors are
read out directly by the data acquisition (DAQ) system. Below are two designs under consideration for the photon detection system
•The light guide is 8.6 cm by 210 cm, significantly increasing the surface
area for light detection.
•Four groups of three passively ganged SiPMs are coupled to the light
guide.
•The light guide and SiPMs fit into the 10 photon detector slots per Anode
Plane Assembly (APA) in protoDUNE.
•The first wavelength shift occurs on TPB-doped radiator plates outside
the light guides, converting VUV -128 nm to 430 nm blue light.
•The light guide itself is made of EL-280, a fluorescent plastic that absorbs
430 nm light and re-emits it at 490 nm green light.
•Light measurements suggest an overall detection efficiency of about
0.23% per detector module in DUNE, corresponding to an effective area
of 4.1 cm² per module in protoDUNE.
•The light guide is coated with tetraphenyl butadiene (TPB), which shifts
incident VUV light to 430 nm.
•The 430 nm light is transported within the light guide bar via total
internal reflection.
•The light guide is coupled with 12 channels of SensL Series C SiPMs. The
430 nm light falls within the peak detection spectrum of these SiPMs,
ensuring effective light capture and conversion.
•Measurements suggest that the detection efficiency of dip-coated light
guides is comparable to the double-shifted design, with an efficiency of
about 0.23%.
•Dip-Coated Light Guide has straight forward design compared to Double-
Shifted Light guide.
SiPM Array

74. Kaushal Patel (NIU) 73
SiPM
3D printed custom case for SiPM to
attach to the tile, does not require glue
compared to two designs in the last
slide
Flat Shape
Spherical Shape
UV light placement
Objective: Investigate the response of the tile by utilizing UV light to illuminate it and allow light to travel through. This
study aims to compare two design concepts: a spherical shape and a flat top shape on the tile. The goal is to determine
which shape maximizes photon detection efficiency. The findings of this study are critical, as they could potentially lead
to the implementation of these designs in the DUNE experiment by shifting VUV light to more visible wavelengths for
enhanced detection.
Tile
1 2 3 4 5 6 7 8
1 2 3 4 5 6 7 8
Kaushal Patel HGCAL, NICADD,2021
Kaushal Patel HGCAL, NICADD,2021

75. Kaushal Patel (NIU) 74
0
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CUrrent, nA
Position
6x6 MPPC operrating Voltage 53.5 (Flat)
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Current, nA
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6X6 MPPC Operrating Voltage 53.5 (Spherical)
Shows the data of SiPM in each location it was moved. Measurement was taken for each flat shape and spherical shape located on the tile.

76. Kaushal Patel (NIU) 75
0
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Graph of both Flat and Spherical Data Combined
Data is crystal clear Spherical shape gives the maximum light response from the tile.

77. •Driven by high luminosity and radiation (transverse and longitudinal).
•Radiation studies of scintillator tiles and SiPM are well understood.

•Investigations were conducted to assess the light yield and spatial uniformity across diverse configurations of
scintillator tiles. In this research, the scintillation light emitted by each scintillator was captured using a SiPM
employing the SiPM-on-tile technique, for in preparation for the High-Granularity Calorimeter upgrade for CMS.
A substantial portion of the endcap will be constructed using scintillator material and using SiPM. The intricacies
of handling a vast array of tiles, each of varying sizes, and efficiently wrapping them using the wrapping machine
pose a formidable challenge in this endeavor.
•NICADD results of LY ESR wrapped scintillator tiles are slightly better then DESY.
•NICADD – developed the SiPM-on-Tile Concept.
•Upgrades of the HGCAL are optimized by low cost/area active materials.
•Managed and operated by Northern Illinois Center for Accelerator and Detector Development (NICADD) and
implanted through regular meetings, workshops, trainings and CMS collaboration with NICADD, Fermilab, DESY,
CERN and international groups.
•Research funded by National Science Foundation (NSF) - award number: 1757597
•Dune studies and research was done, for optimal physics performance of the light guide.
•At NICADD, our accelerator and beam physics group stands as the strongest university-based accelerator physics
group in Illinois, reflecting our commitment to excellence and innovation in the field.
Kaushal Patel (NIU) 76
Acknowledgements: Vishnu Zutshi, Alexandre Dychkant,
Kurt Francis, Mike Eads and Jahred Adelman
https://www.niu.edu/clas/nicadd/about/index.shtml