Pelletron accelarator

This is one of the interesting topic in physics. These pelletron accelerator is a modern thing of van de graff accelerator.

1. PELLETRON ACCELARATOR by, A.K.Raaha Sutha Lady Doak College

2. Van de graaff generator It is an electrostatic generator. It can accumulate electric charge on a hollow metal globe, creating very high electric potentials. This high potential is used to accelerate subatomic particles to high speed & to generate energetic particle and x-ray beams in nuclear medicine field. Turnout: open air van de graaff =5MV, Industrial machines are enclosed with pressurized tank of insulating gas=25MV.

3. Insertion-Pelletron The basic pelletron inductive charging system was invented by Dr.James A.Ferry Pelletron is an accelerator for electrostatic particles.(charge generator) Output voltage: small units-500kV &beam energy-1MV. It is a collaborative project between BARC & TIFR has been serving as a major facility of heavy ion accelerator based research in India. 30000 accelerators in operation around the world.

4. Working: The system is enclosed by a pressure vessel filled with insulating gas(SF6) &an evacuated beam line. A chain of pellets used for carrying charge to the terminal hence it is called pelletron. The negative ions on traversing through the accelerating tubes from the column top of the tank to the positive terminal get accelerated. Energetic negative ions stripped by the stripper foil. P ositive ions are repelled away from the positively charged terminal and are accelerated to ground potential.

5. Same terminal potential is used twice to accelerate the ions . The ions are bent into horizontal plane by analyzing magnet, which also selects a particular beam of ion and charge state . The switching magnet diverts the high energy ion beams into a pre-selected beam line of various beam lines The entire machine is computer controlled and is operated from the control room.

6. PELLETRON CHARGING SYSTEM These systems have fragile electronics in the high voltage column . Difficulty: To diagnose and expensive to repair. Pelletron chains made upon metal pellets. It connected by insulating nylon links. Parts: Pulley(30-60cm diameter),suppressor electrode, high voltage terminal. Charging current -100-200uA.

7. AMS(accelerator mass spectrometry) development: Low beam current application.(except very high DC electron recirculation pelletron) High precision AMS measurement-500kV to 5MV The design of multi cathode SNICS(Source of Negative Ions by Cs-Sputtering) source for the use of both gas and solid samples within a single source. New diagnostics is being developed for very low beam currents. Latest design of the low current beam profile monitor(LCBPM) will also be presented.

8. PELLETRON IN INDIA: Pelletron above 5MV: Tata institute of fundamental research-14UD in Mumbai, India. Inter –University Accelerator centre(IUPAC)-15UD in New Delhi, India. Pelletron with 3MV: Institute of Physics-9SDH-2 in Bhubaneswar ,India.

9. RECENT DEVELOPMENTS: 300 pelletron chain assemblies in use in 24 countries . National Electrostatic Corporation(NEC) has manufactured 79 ion beam systems. 17 of these pelletron systems were designed with MeV ion implantation capability. 8 were designed for production ion implantation with max beam energy of 4 MeV.

10. ADVANTAGE: Excellent voltage stability. No spark damage intrinsically protected. High efficiency No electronic diagnostic equipment required. Virtually insensitive to moisture. Long life(over 50000 hours reported). Simple and reliable. Proven to over 30MV.