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Study of neutron detection technologies using ⁶Li as a replacement of ³He

Paper presented at INMM 2017, 58th Annual Meeting Institute of Nuclear Materials Management, July 2017, Indian Wells
 
: Berky, Wolfram; Bornhöft, Charlotte; Friedrich, Hermann; Köble, Theo; Risse, Monika; Rosenstock, Wolfgang; Schumann, Olaf

:
Volltext urn:nbn:de:0011-n-4743439 (977 KByte PDF)
MD5 Fingerprint: 0274968301339ed0453d2dcea6dacf9a
Erstellt am: 2.12.2017


2017, 10 Seiten
Institute of Nuclear Materials Management (INMM Annual Meeting) <58, 2017, Indian Wells/Calif.>
Englisch
Vortrag, Elektronische Publikation
Fraunhofer INT ()
neutron measurement; neutron detection material; ³He replacement

Abstract
Within the past decade a significant shortage of ³He has occurred. Since this material is widely used in neutron detection applications, e.g. by first responders, during on-site inspections, and in safeguard applications where nuclear and radioactive material has to be localized and possibly identified, replacement materials need to be considered, selected, implemented in a corresponding detector, and thoroughly tested. One of these promising materials is ⁶Li which is utilized in detector applications such as ⁶LiF/ZnS, CLYC (Cs₂LiYCl₆:Ce), and CLLB (Cs₂LiLaBr₆:Ce). The latter two detector types even offer the possibility of measuring gamma radiation simultaneously with good discrimination capability between neutrons and gammas. Within the detection materials neutrons are captured by ⁶Li, triggering the nuclear reaction ⁶Li(n,t)α. The secondary particles then create light pulses in the scintillation crystal which ultimately serve as detection signals. Due to the large Q-value of the reaction of 4.78 MeV, the signals are of the same order of magnitude as those of high energetic gamma photons. The discrimination of neutron and gamma radiation can be realized by pulse shape analysis. Measurements with all detector types mentioned above have been performed. We have verified these detectors’ capabilities with measurements of several neutron sources, also compared to a detector filled with ³He. The possibility of detecting such a (hidden and/or shielded) source which creates a radiation field only slightly above the background radiation level is of particular interest. Other figures of interest were the FWHM (full width at half maximum) of the CLYC and CLLB gamma spectra and the detectors’ efficiencies, especially with regard to a detector with ³He tubes. The results of these verification tests will serve as supportive information for first responders and other experts who work in the field of nuclear safety and security regarding suitable neutron detection materials without the rare ³He.

: http://publica.fraunhofer.de/dokumente/N-474343.html