Low-level measuring techniques for neutrons: High accuracy neutron source strength determination and fluence rate measurement at an underground laboratory

Journal Article · Thu Aug 08 00:00:00 EDT 2013 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.4818078· OSTI ID:22218201

Zimbal, Andreas; Reginatto, Marcel; Schuhmacher, Helmut; Wiegel, Burkhard ^[1]; Degering, Detlev ^[2]; Zuber, Kai ^[3]

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1. Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig (Germany)
2. Verein für Kernverfahrenstechnik und Analytik Rossendorf e. V. (VKTA), D-01314 Dresden (Germany)
3. Technische Universität Dresden, D-01069 Dresden (Germany)

We report on measuring techniques for neutrons that have been developed at the Physikalisch-Technische Bundesanstalt (PTB), the German National Metrology Institute. PTB has characterized radioactive sources used in the BOREXINO and XENON100 experiments. For the BOREXINO experiment, a {sup 228}Th gamma radiation source was required which would not emit more than 10 neutrons per second. The determination of the neutron emission rate of this specially designed {sup 228}Th source was challenging due to the low neutron emission rate and because the ratio of neutron to gamma radiation was expected to be extremely low, of the order of 10{sup −6}. For the XENON100 detector, PTB carried out a high accuracy measurement of the neutron emission rate of an AmBe source. PTB has also done measurements in underground laboratories. A two month measurement campaign with a set of {sup 3}He-filled proportional counters was carried out in PTB's former UDO underground laboratory at the Asse salt mine. The aim of the campaign was to determine the intrinsic background of detectors, which is needed for the analysis of data taken in lowintensity neutron fields. At a later time, PTB did a preliminary measurement of the neutron fluence rate at the underground laboratory Felsenkeller operated by VKTA. By taking into account data from UDO, Felsenkeller, and detector calibrations made at the PTB facility, it was possible to estimate the neutron fluence rate at the Felsenkeller underground laboratory.

• OSTI ID: 22218201
• Journal Information: AIP Conference Proceedings, Vol. 1549, Issue 1; Conference: LRT 2013: 4. international workshop on low radioactivity techniques, Assergi (Italy), 10-12 Apr 2013; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
ACCURACY
ASSE SALT MINE
CALIBRATION
DATA ANALYSIS
DESIGN
GAMMA DETECTION
GAMMA RADIATION
HELIUM 3
NEUTRON DETECTION
NEUTRON EMISSION
NEUTRON FLUENCE
NEUTRON SOURCES
NEUTRONS
PROPORTIONAL COUNTERS
SOLID SCINTILLATION DETECTORS
THORIUM 228
UNDERGROUND