Temperature sensitivity of a Bonner-sphere LiI(Eu) scintillation neutron detector

Conference · Tue Dec 31 23:00:00 EST 1991 · Transactions of the American Nuclear Society; (United States)

OSTI ID:6955909

West, L; Lemley, E C ^[1]

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1. Univ. of Arkansas, Fayetteville (United States)

Neutron spectroscopy with Bonner spheres involves a sequence of measurements with a LiI(Eu) scintillation detector with several moderating spheres. The measured quantity is the count rate of the {sup 6}Li(n,{alpha}){sup 3}H reaction, using either a net or gross integral over a preset limited range of the pulse-height distribution to discriminate against the ever-present gamma radiation in neutron environments. Unfolding codes utilize these count rates to produce neutron fluence spectra. The accuracy of the measured count rate depends, among other things, on the overall stability of the detector and electronics system. Elevated temperatures may alter count rates measured with scintillation radiation detectors because of increased thermoionic emission of the cathode and dynodes at higher temperatures. Field measurements with Bonner spheres in operating nuclear power reactor containment buildings often encounter temperatures as high as 50 C ({approximately}120 F). Hence, the effect of higher temperatures on the {sup 6}LiI(Eu) crystal and photomultiplier tube of the Bonner sphere has been investigated and documented. The nominal temperature sensitivity of the 4-mm LiI(Eu) detector is {approximately}0.12%/{degree}C between 25 and 50 C. On an absolute scale, the difference in count rate within a 25C range translates to an {approximately}4% error, according to the measurements presented.

• OSTI ID: 6955909
• Report Number(s): CONF-920606--
• Journal Information: Transactions of the American Nuclear Society; (United States), Journal Name: Transactions of the American Nuclear Society; (United States) Vol. 65; ISSN TANSA; ISSN 0003-018X
• Country of Publication: United States
• Language: English

Related Subjects

440103* -- Radiation Instrumentation-- Nuclear Spectroscopic Instrumentation
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
AC SYSTEMS
BONNER SPHERE SPECTROMETERS
CATHODES
CONTAINMENT
CONTAINMENT SYSTEMS
DYNODES
ELECTRODES
ELECTRONIC EQUIPMENT
EMISSION
ENGINEERED SAFETY SYSTEMS
EQUIPMENT
HEAVY WATER
HYDROGEN COMPOUNDS
MEASURING INSTRUMENTS
NEUTRON SPECTROMETERS
NEUTRON SPECTROSCOPY
OXYGEN COMPOUNDS
PERFORMANCE
PHOTOMULTIPLIERS
PHOTOTUBES
POWER SUPPLIES
POWER SYSTEMS
RADIATION DETECTORS
SCINTILLATION COUNTERS
SENSITIVITY
SPECTROMETERS
SPECTROSCOPY
TEMPERATURE DEPENDENCE
THERMIONIC EMISSION
WATER