developments in gamma spectrometry alexandria university, faculty of engineering nuclear engineering...

Developments in gamma spectrometryDevelopments in gamma spectrometry

Alexandria University, Faculty of Engineering Nuclear Engineering Department

JINR, Frank Laboratory of Neutron Physics

Department of Neutron Activation Analysis

Ashraf KAKA

Supervisor: Dr. Marina FRONTASYEVA

General considerations in General considerations in gamma-ray spectrometrygamma-ray spectrometry

11 Photoelectric absorptionPhotoelectric absorption

22 Compton scatteringCompton scattering

33 Pair productionPair production

Photoelectric absorptionPhotoelectric absorption

Compton ScatteringCompton Scattering

Pair ProductionPair Production

511 eV

Probability ofProbability of

interaction of photon interaction of photon

with matterwith matter

Gamma-ray spectrometer systemGamma-ray spectrometer system

PreamplifierPreamplifier

The pulses produced in the detector are The pulses produced in the detector are

very small and so the charge sensitive very small and so the charge sensitive

preamplifier, usually a field-effect transistor preamplifier, usually a field-effect transistor

(FET), is mounted as close to the detector (FET), is mounted as close to the detector

as possibleas possible

AmplifierAmplifier

The amplifier increases the size of the The amplifier increases the size of the small signal from the output of the small signal from the output of the preamplifier to a pulse of amplitude up to preamplifier to a pulse of amplitude up to about 10 V, dependent on the gain settingabout 10 V, dependent on the gain setting

The second purpose of the amplifier is to The second purpose of the amplifier is to improve the signal to noise ratio of the improve the signal to noise ratio of the given pulsesgiven pulses

Photo multiplier tubePhoto multiplier tube (PMTS)(PMTS)

ConclusionConclusion

The quality of gamma-spectrometers can The quality of gamma-spectrometers can be improved by using of a small size PMTbe improved by using of a small size PMT

to increase the efficiency of the detector to increase the efficiency of the detector and to minimize its sizeand to minimize its size

Thank you for attentionThank you for attention!!