Speaker
Mr
Kevin Pritchard
(NCNR)
Description
The NIST Center for Neutron Research is finalizing the design of a novel scintillating neutron detector for its CANDOR neutron scattering instrument. The detectors in the chromatic analyzer must be extremely thin (~1.5 mm) and highly efficient (~90% sensitivity for 3.3 meV neutrons. To that end the detectors consist of 6LiF:ZnS(Ag) plastic scintillator in which wavelength shifting (WLS) fibers have been embedded. Scintillation light collected in the WLS fibers is read out using a silicon photomultiplier (SiPM). The signal from the SiPM is digitized and processed by a field programmable gate array using a pulse shape discrimination algorithm.
Discriminating neutron capture events from other phenomena presents a number of challenges for both raw sensitivity and count rate. We describe our efforts to cope with these issues.
At the present time the detectors exhibit a neutron sensitivity of ~90% for 3.3 meV neutrons with a gamma rejection ratio of ~10E-7 at count rates exceeding 10000 counts per second.
Author
Mr
Kevin Pritchard
(NCNR)
Co-authors
Dr
Alon Osovizky
(NCNR, Rotem Industries Ltd.)
Dr
Charles Majkrzak
(NCNR)
Mr
Jeff Ziegler
(NCNR)
Dr
Nicholas Maliszewskyj
(NCNR)
Mr
Peter Tsai
(NCNR)