11 Nuclear Physics - Radioactivity 11.5 Gamma Particles - Energy - Compton Effect
Internal conversion in 137m Ba with Multi Channel Analyser (MCA)
P2524515
Gamma-spectrum of 137Cs.
Principle
Gamma detector
The radiation emitted during the decay of the 137Cs isotope is measured with a scintillation detector and the energyspectrum determined with a pulse height analyzer. The spectrum contains fractions due to a gamma-transition and fractions originating from a characteristic X-ray radiation. The areas of the fractions in question are determined and the conversion factor obtained from them. Tasks 1. Measurement of the g-spectrum of 137Cs using a scintillation detector. 2. Determination of the conversion factor of the 137mBa excited nucleus. What you can learn about ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪
g-radiation, Nuclear transitions Transition probability Duration, Metastable states Isotopic spin quantum Numbers Rules governing selection Multipole radiation, Isomeric nuclei Photonuclear reaction, Conversion electron Characteristic X-ray radiation Scintillation detectors
Function and Applications To detect gamma, beta and x-rays. Large volume thallium doped NaI-crystal in light-tight capsule, with photomultiplier with mumetal shielding mounted in holder with rod. Equipment and technical data ▪ ▪ ▪ ▪
Crystal: NaI (Ta). Crystal dimensions (mm): 38 x 50.8. Thickness of Al envelope: 0.4 mm. Operation voltage: 600..1100 V.
09101-00
Main articles Gamma detector Multi channel analyser Radioactive source Cs-137, 37 kBq Operating unit for gamma detector measure Software multi channel analyser
09101-00 13727-99 09096-01 09101-93 14452-61
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