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LUND UNIVERSITY LIBRARIES

Study of Gamma-ray Response of LaBr3:Ce Scintillation Detectors for an Iridium Coincidence Spectrometer

Qatamin, Aymen LU (2012) FYSM31 20121
Department of Physics
Nuclear physics
Abstract
Presently, the development of the second generation Ir coincidence spectrometer is talking place at the division of Nuclear Physics. There is a large need among geologists to measure trace quantities of Ir in different geological layers and correlate the age of the layer with
different large meteorite impacts. The first generation Ir spectrometer was based on a coincidence measured by two HPGe detectors, whike the new spectrometer will be based on a triple coincidence measurement in 14 LaBr detectors chosen from their extreamly good time behavior.

In this work, the first delivered module has been studied and performance has been verified. The linearity response, intrinsic activity and scattering effect of the 25.4´25.4´50.8 mm LaBr3:Ce... (More)
Presently, the development of the second generation Ir coincidence spectrometer is talking place at the division of Nuclear Physics. There is a large need among geologists to measure trace quantities of Ir in different geological layers and correlate the age of the layer with
different large meteorite impacts. The first generation Ir spectrometer was based on a coincidence measured by two HPGe detectors, whike the new spectrometer will be based on a triple coincidence measurement in 14 LaBr detectors chosen from their extreamly good time behavior.

In this work, the first delivered module has been studied and performance has been verified. The linearity response, intrinsic activity and scattering effect of the 25.4´25.4´50.8 mm LaBr3:Ce detectors has been measured . Energy resolution 3.1%, 3.2%, 2.6% at 662 keV has been achieved for three available crystals. High timing resolution on the level (300 ± 1.3) ps measured using two LaBr3:Ce detectors and 22Na annihilation source.

Using 60Co source placed at distance 15 cm from detectors the intrinsic photopeak efficiency of detectors was calculated to be (1.42± 0.3) ´10-2 and (1.12 ± 0.2) ´10-2 for 1137 keV and 1332 keV γ-lines. Moreover, using γ-ray spectra for Ir-sample available the minimum detectable mass using three detectors setup was calculated. The result was (60 ± 0.3) μg/g in one hour. According to this result the final minimum detectable mass capability for fully equipped LWA-ICA instrument was estimated to be on the level of 10-12 g/g in one hour. (Less)
Abstract (Swedish)
Vid avdelningen för kärnfysik utvecklas för närvarande andra generationens Ir-koincidensspektrometer. Anledningen till detta är att det finns ett stort behov bland geologer att mäta spårkvantiteter av Iridium i olika geologiska skikt för att korrelera skiktens ålder med
eventuella stora meteoritnedslag. Första generationens spektrometer byggde på en dubbelkoincidens mätt med två HPGe-detektorer, medan andra generationens kommer att bygga på en trippelkoincidens mätt med 14 stycken LaBr-detektorer valda utifrån deras extremt goda tidsegenskaper.
I detta arbete har de först levererade modulernas egenskaper studerats och verifierats.
Grundläggande spektroskopiska egenskaper hos LaBr3:Ce-detektorer, med storleken 25.4 cm×25.4 cm×50.5× cm,... (More)
Vid avdelningen för kärnfysik utvecklas för närvarande andra generationens Ir-koincidensspektrometer. Anledningen till detta är att det finns ett stort behov bland geologer att mäta spårkvantiteter av Iridium i olika geologiska skikt för att korrelera skiktens ålder med
eventuella stora meteoritnedslag. Första generationens spektrometer byggde på en dubbelkoincidens mätt med två HPGe-detektorer, medan andra generationens kommer att bygga på en trippelkoincidens mätt med 14 stycken LaBr-detektorer valda utifrån deras extremt goda tidsegenskaper.
I detta arbete har de först levererade modulernas egenskaper studerats och verifierats.
Grundläggande spektroskopiska egenskaper hos LaBr3:Ce-detektorer, med storleken 25.4 cm×25.4 cm×50.5× cm, har mätts upp. En energiupplösning på 3.1 %, 3.2 % respektive 2.6 % har uppnåtts för tre tillgängliga kristaller. Hög tidsupplösning på nivån (300 ± 1.3) ps har mätts upp med hjälp av två LaBr3:Ce-detektorer och ett 22Na-annihillationspreparat. Lineariteten hos LaBr3:Ce-detektorerna har mätts upp. Spridningseffekten för två LaBr3:Cedetektorer har utvärderats. Den intrinsiska aktiviteten hos LaBr3:Ce har undersökts. Med hjälp av ett 60Co-preparat har detektorernas intrinsiska effektivitet för fototoppen beräknats till
(1.42 ± 0.3)×10-2 och (1.12 ± 0.2)×10-2 för g-linjerna vid 1137 keV respektive 1332 keV.
Genom att använda gammastrålningsspektra från ett tillgängligt Ir-prov har den minsta detekterbara massan för de tre detektorerna kunnat beräknas. Resultatet är (60 ± 0.3) μg/g på en timme. Baserat på detta resultat har den slutgiltiga minsta detekterbara massan för ett fullt
utbyggt LWA-ICA-instrument uppskattas vara ungefär 10-12 g/g på en timme. (Less)
Please use this url to cite or link to this publication:
author
Qatamin, Aymen LU
supervisor
organization
course
FYSM31 20121
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
3048261
date added to LUP
2012-09-24 11:43:47
date last changed
2012-11-12 21:06:00
@misc{3048261,
  abstract     = {{Presently, the development of the second generation Ir coincidence spectrometer is talking place at the division of Nuclear Physics. There is a large need among geologists to measure trace quantities of Ir in different geological layers and correlate the age of the layer with
different large meteorite impacts. The first generation Ir spectrometer was based on a coincidence measured by two HPGe detectors, whike the new spectrometer will be based on a triple coincidence measurement in 14 LaBr detectors chosen from their extreamly good time behavior.

In this work, the first delivered module has been studied and performance has been verified. The linearity response, intrinsic activity and scattering effect of the 25.4´25.4´50.8 mm LaBr3:Ce detectors has been measured . Energy resolution 3.1%, 3.2%, 2.6% at 662 keV has been achieved for three available crystals. High timing resolution on the level (300 ± 1.3) ps measured using two LaBr3:Ce detectors and 22Na annihilation source.

Using 60Co source placed at distance 15 cm from detectors the intrinsic photopeak efficiency of detectors was calculated to be (1.42± 0.3) ´10-2 and (1.12 ± 0.2) ´10-2 for 1137 keV and 1332 keV γ-lines. Moreover, using γ-ray spectra for Ir-sample available the minimum detectable mass using three detectors setup was calculated. The result was (60 ± 0.3) μg/g in one hour. According to this result the final minimum detectable mass capability for fully equipped LWA-ICA instrument was estimated to be on the level of 10-12 g/g in one hour.}},
  author       = {{Qatamin, Aymen}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Study of Gamma-ray Response of LaBr3:Ce Scintillation Detectors for an Iridium Coincidence Spectrometer}},
  year         = {{2012}},
}