Use of delayed gamma rays for active non-destructive assay of ²³⁵U irradiated by pulsed neutron source (plasma focus)

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• 作者：Sanjay Andola^a ; Ram Niranjan^a ; T.C. Kaushik^a ; ^{tckk@barc.gov.in" class="auth_mail} ; R.K. Rout^a ; Ashwani Kumar^b ; D.B. Paranjape^b ; Pradeep Kumar^b ; B.S. Tomar^b ; K.L. Ramakumar^b ; S.C. Gupta^a
• 关键词：Non-destructive assay ; Active interrogation ; Delayed gammas ; 235U ; Plasma focus ; Pulsed neutron source
• 刊名：Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
• 出版年：21 July 2014
• 年：2014
• 卷：753
• 期：Complete
• 页码：138-142
• 全文大小：717 K

文摘

A pulsed neutron source based on plasma focus device has been used for active interrogation and assay of ²³⁵U by monitoring its delayed high energy 纬-rays. The method involves irradiation of fissile material by thermal neutrons obtained after moderation of a burst of neutrons emitted upon fusion of deuterium in plasma focus (PF) device. The delayed gamma rays emitted from the fissile material as a consequence of induced fission were detected by a large volume sodium iodide (NaI(Tl)) detector. The detector is coupled to a data acquisition system of 2k input size with 2k ADC conversion gain. Counting was carried out in pulse height analysis mode for time integrated counts up to 100 s while the temporal profile of delayed gamma has been obtained by counting in multichannel scaling mode with dwell time of 50 ms. To avoid the effect of passive (natural) and active (from surrounding materials) backgrounds, counts have been acquired for gamma energy between 3 and 10 MeV. The lower limit of detection of ²³⁵U in the oxide samples with this set-up is estimated to be 14 mg.