RADIATION SOURCE OF UV-SPECTROSCOPY.pptx

Radiation source or lamp of UV Spectroscopy include various lamp such as a hydrogen discharge lamp,deutorium lamp. Xenon arc lamp ,mercury arc lamp etc .it must be stable.it ,must sufficient intensity for the transmitted energy to be detected.

1. RADIATION SOURCE OF UV-SPECTROSCOPY Presented by -: Prof . Chandgude Varsha .S (SVPM’S College of Pharmacy Malegaon (BK) Baramati 413102)

2. In ultraviolet spectroscopy various radiation source are included such as a -: 1.Mercury ARC LAMP 2.DEUTORIUM LAMP 3.HYDROGEN DISCHARGE LAMP 4.TUNGSTEN LAMP 5.XENON ARC LAMP In all sources excitation is done by passing electron through gas & these collision between electron & gas molecules may result in electronic ,vibrational & rotational excitation in the gas molecules.

3. When the pressure of gas is low ,then only line spectra are emitted. If the pressure of gas is high ,broad spectrs & continuous spectra will be obtained .

4. Requirement of a radiation source 1.It must be stable 2.it must be sufficient for intensity for the transmitted energy to be detected. 3.it must supply continuous radiation over e ntire wavelength region.

5. BASIC PRINCIPLE OF RADIATION SOURCE A hollow tube Fill with any gas with full pressure it generate atoms . Also pass the electricity to hollow tube it generate the electrons. collision between atoms & electrons it generate vibrational energy & emits the radiation .

6. MercURY ARC LAMP-: 1.MERCURY ARC LAMP IS UNDER HIGH PRESSURE & EXCITATION OF MERCURY ATOMS IS DONE BY ELECTRIC DISCHARGE.

7. 2. A hollow tube filled with mercury gas or vapor at high pressure generates atoms. When electricity passes through the tube, it produces electrons. The collision between these atoms and electrons generates vibrational energy, which in turn emits radiation . Deuterium lamp -: if deuterium lamp is used in place of hydrogen lamp ,the intensity of radiation emission is 3-5 times more than hydrogen lamp.

8. It is more expensive than hydrogen lamp It is used when high intensity required . Hydrogen discharge lamp -: hydrogen GAS STORED UNDER HIGH PRESSURE WHEN AN ELECTRIC DISCHARGE PASSED THROUGH LAMP .EXCITED HYDROGEN MOLECULE WILL PRODUCED EMIT UV RADIATIONS. HYDROGEN DISCHARGE LAMP CONSIST OF HYDROGEN GAS UNDER HIGH PRESSURE ,HYDROGEN MOLECULE ARE EXCITED ELECTRICALLY& EMIT UV RADIATION.THE HIGH PRESSURE BRINGS ABOUT COLLISIONS BETWEEN HYDROGEN MOLECULE& RESULTING IN PRESSURE BROADENING. HYDROGEN TO EMIT CONTINUM ( BROAD BAND) RATHER THAN SIMPLE HYDROGEN LINE SPECTRUM

9. TUNGSTEN LAMP -: The tungsten lamp is similar in its function to an electric light bulb.it is tungsten filament heated electrically It contain two filament In this lamp tungsten wire heated ,then increase the temperature & emits the radiation To maintain a constant intensity ,the electrical current to the lamp must be carefully controlled. It is also called as a household lamp. Lamps are generally stable,robust & easy to use

10. XENON ARC/DISCHARGE LAMP -: IN THIS LAMP XENON GAS STORED UNDER PRESSURE THE XENON LAMP POSSESSE TWO TUNGSTEN ELECTRODE SEPARATED BY ABOUT 8MM. TWO TUNGSTEN ELECTRODE BY APPLYING LOW VOLTAGE,THE ULTRAVIOLET LIGHT IS PRODUCED. THE INTENSITY OF ULTRAVIOLET RADIATION PRODUCED BY XENON DISCHARGE LAMP IS MUCH GREATER THAN HYDROGEN LAMP .