Very Large Boron Trifluoride Proportional Counters
More than 50 very large BF/sub 3/ counters, each approximately 6 ft (180 cm) long and 6 in. (15 cm) in diameter were made for cosmic-ray monitors. During the fabrication of these counters, the characteristics at varying gas pressures were studied and the alpha backgrounds of the various metals used for cathodes were determined. The counters have excellent characteristics at pressures up to 30 cm Hg and perfectiy acceptable characteristics to 80 cm Hg pressure. With anode diameter 0.008 in. (0.2 mm) and gas amplification 35, the operating voltage for a filling of 20 cm Hg pressure of pure BF/sub 3/ is 2800 v; at 30 cm Hg it is 3400 v. Counters with copper cathodes have backgrounds due to residual alpha contamination of about 2 counts/min, and with stainless steel cathodes, about 5 counts/min. Using a BF/sub 3/-Ar filling, a value of 5.30 plus or minus 0.05% was obtained for the branching ratio of the B/sup 10/(n, alpha ) Li/sup 7/ reaction.
- Research Organization:
- Atomic Energy of Canada Ltd., Chalk River, Ont.
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-17-032447
- OSTI ID:
- 4670758
- Journal Information:
- Review of Scientific Instruments, Journal Name: Review of Scientific Instruments Journal Issue: 7 Vol. 34; ISSN 0034-6748; ISSN RSINAK
- Publisher:
- American Institute of Physics (AIP)
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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Related Subjects
ANODES
ARGON
ATOMIC MODELS
BACKGROUND
BERYLLIUM 10
BORON 10
BORON FLUORIDES
CAPTURE
CATHODES
CONTAMINATION
COPPER
COSMIC RADIATION
CROSS SECTIONS
ELECTRIC POTENTIAL
ELECTRONS
ENERGY
ENERGY LEVELS
ENERGY RANGE
EXCITATION
FABRICATION
FREQUENCY
GASES
HELIUM
HYDROGEN
INSTRUMENTS AND INSTRUMENTATION
INTERACTIONS
IONS
LIGHT
LITHIUM 6
LITHIUM 7
MEASURED VALUES
MONITORING
NEON
NEUTRON BEAMS
NEUTRONS
NUCLEAR REACTIONS
OPERATION
POLARIZATION
PRESSURE
PROPORTIONAL COUNTERS
PROTONS
SCATTERING
SPECTRA
STAINLESS STEELS
ULTRAVIOLET RADIATION