Modified A-B remmeter with improved directional dependence and thermal neutral sensitivity

Conference · Mon Jun 27 04:00:00 EDT 1977

OSTI ID:7300390

Hankins, D E

The Andersson-Braun remmeter was modified to improve the directional dependence of the instrument to thermal and fast neutrons and increase its sensitivity to thermal neutrons. The modifications consist of partially rounding the end of the instrument, moving the BF/sub 3/ tube forward by /sup 1///sub 2/ in., increasing the size of the holes in the boron-loaded polyethylene sleeve, replacing one of the boron-loaded end plugs with a polyethylene plug, changing the location of the other end plug, and adding a small disk of cadmium over the hole where the BF/sub 3/ tube enters the moderator. The cost of making these modifications to the Lawrence Livermore Laboratory Andersson-Braun remmeters is approximately $50.00 each. These modifications to the instrument increase the thermal neutron sensitivity by a factor of approximately 3 when exposed at the side and a factor of approximately 9 at the end opposite the instrument packet. The high thermal sensitivity at the instrument packet end (a factor of approximately 17) is eliminated, and the directional dependence to both thermal and fast neutrons is reduced to +-10% (except at the instrument packet end). The sensitivity of the instrument to fast neutrons is increased by approximately 15%. The sensitivity of the modified remmeter to intermediate-neutron energy is increased, and is similar to that of the 9-in. sphere. The readings of the modified instrument, the Andersson-Braun remmeter, and the 9-in.-sphere remmeter are compared with numerous spectra encountered in field application.

• Research Organization: California Univ., Livermore (USA). Lawrence Livermore Lab.
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 7300390
• Report Number(s): UCRL-78929; CONF-770720-1
• Country of Publication: United States
• Language: English

Related Subjects

440101* -- Radiation Instrumentation-- General Detectors or Monitors & Radiometric Instruments
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
BARYONS
BF3 COUNTERS
ELEMENTARY PARTICLES
FAST NEUTRONS
FERMIONS
HADRONS
MEASURING INSTRUMENTS
MODIFICATIONS
NEUTRON DETECTION
NEUTRON DETECTORS
NEUTRONS
NUCLEONS
ORGANIC COMPOUNDS
ORGANIC POLYMERS
POLYETHYLENES
POLYMERS
POLYOLEFINS
PROPORTIONAL COUNTERS
RADIATION DETECTION
RADIATION DETECTORS
SENSITIVITY
THERMAL NEUTRONS