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

Conference · Wed Jan 01 00:00:00 EST 1992 · 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-; CODEN: TANSA
• Journal Information: Transactions of the American Nuclear Society; (United States), Vol. 65; Conference: American Nuclear Society annual meeting, Boston, MA (United States), 7-12 Jun 1992; ISSN 0003-018X
• Country of Publication: United States
• Language: English

Related Subjects

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