Calibration of the NPL standard Ra-Be photoneutron sources by an improved manganese sulphate bath technique

Axton, E.J.; Cross, Paul C.; Robertson, J.C.

doi:10.1016/0368-3230(65)90050-9

Cited by 36 publications

(12 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The neutron fluences from Cf and Am-Be sources were obtained from the neutron emission rate and the anisotropy [14]. The neutron emission rates were calibrated for the Am-Be source by the manganese bath method at NPL [15] and for the Cf source by a method using the graphite pile at NMIJ [16]. Monoenergetic neutrons were produced at 144 keV and 565 keV by the Li(p,n) Be reaction and at 5 MeV by the D(d,n) He reaction with a Van de Graaff accelerator and at 14.8 MeV by the T(d,n) He reaction with a Cockcroft-Walton accelerator [17].…”

Section: Methodsmentioning

confidence: 99%

Development of a Compact Flat Response Neutron Detector

Harano

Matsumoto

Nishiyama

et al. 2011

IEEE Trans. Nucl. Sci.

View full text Add to dashboard Cite

Long counters are widely used as neutron fluence monitors for their flat response. However, a bulky neutron moderator is required to achieve the flat response, which can be a disadvantage for portability and an undesirable source of scattered neutrons. Reducing the size of the moderator degrades the flat response, especially for high-energy neutrons. We propose a new method to reduce the size of the moderator while keeping a flat response, and we develop a compact flat-response neutron detector. The detector consists of two small spherical 3 He proportional counters embedded at appropriate positions in a compact cylindrical polyethylene moderator. The sensitivity ratio between the two counters was adjusted to provide a flat response in the total outputs from the two counters. We demonstrated by MCNPX calculations and response measurements for Cf and Am-Be neutrons and monoenergetic neutrons that the present detector had a sensitivity comparable to long counters with a good flat response in a wide energy range up to 20 MeV while being only one-fifth of the weight of long counters. The positions of the effective center were determined as a function of neutron energy. We also proposed a method to evaluate the neutron energy using the detector, which will allow various new applications taking advantage of the ability to measure neutron fluence and energy at the same time.Index Terms-Effective center, flat response, long counter, neutron energy evaluation, neutron fluence measurement.

show abstract

Section: Methodsmentioning

confidence: 99%

Development of a Compact Flat Response Neutron Detector

Harano

Matsumoto

Nishiyama

et al. 2011

IEEE Trans. Nucl. Sci.

View full text Add to dashboard Cite

show abstract

“…The neutron emission rate of NBS-II was taken to be 1.174 × 106 see -1 :k 0.5~ (referred to June, 1972), based on independent calibrations by four laboratories: the National Bureau of Standards (Noyce, 1963;Spiegel, 1972), the International Bureau of Weights and Measures (Huynh, 1970), the National Physical Laboratory (Axton, 1965) and Argonne National Laboratory (DeVolpi, 1969). The respective values reported by NBS, BIPM, NPL and ANL were 1.176, 1.177 ± 0.003, 1.168 and 1.174 ± 0.004 in units of 106 sec -1 referred to June, 1972.…”

Section: The Average Scalar Fluxmentioning

confidence: 99%

An absolute determination of the 235U fission cross section at 964 keV

Gilliam

Knoll

1975

Annals of Nuclear Energy

View full text Add to dashboard Cite

An absolute measurement of the 235U fission cross section has been carried out using a S4Na-Be photoneutron source with median neutron energy of 964 keV. A symmetric two-foil experiment was set up to measure the fission rate in a low-albedo laboratory, and variations in the sourceto-foil spacing used to determine the room background. Fission fragments passing through a limited solid angle aperture were recorded from each foil by solid state tracketch techniques. The photoneutron source was calibrated after each run using the manganese bath method and the secondary national standard source NBS-II. A computed neutron source spectrum with 32 keV FWHM was derived by the Monte Carlo method and used in reducing the data to a cross section at 964 keV. The final value of 1.21 ~ 0.025 barns is absolute in that, except for small corrections, its determination was independent of any other cross section data.

show abstract

“…The neutron fluences from Cf and Am-Be sources were obtained from the neutron emission rate and the anisotropy [12]. The neutron emission rates were calibrated for the Am-Be source by the manganese bath method at NPL [13] and for the Cf source by the method using the graphite pile at NMIJ [14]. Monoenergetic neutrons were produced at 144 keV, 565 keV and 5 MeV with a Van de Graaff accelerator and at 14.8 MeV with a Cockcroft Walton accelerator [15].…”

Section: Methodsmentioning

confidence: 99%

Development of a compact flat response neutron detector

Harano

Matsumoto

Nishiyama

et al. 2010

IEEE Nuclear Science Symposuim &Amp; Medical Imaging Conference

View full text Add to dashboard Cite

Long counters are widely used as neutron fluence monitors by utilizing their flat-response feature. A bulky neutron moderator is required however to achieve the flatresponse feature, which can be a disadvantage from the viewpoint of portability as well as an undesirable source of scattered neutrons. Just downsizing the moderator deteriorates the flat response especially for high-energy neutrons. We proposed a new method to downsize the moderator with keeping the flat-response feature and developed a compact flat-response neutron detector in the present study. The detector consists of two small spherical 3 He proportional counters embedded in appropriate positions in a compact cylindrical polyethylene moderator. The sensitivity ratio between the two counters was adjusted to provide a flat response in the total outputs from the two counters. It was demonstrated by MCNPX calculations and response measurements for Cf and Am-Be neutrons and monoenergetic neutrons that the present detector had a good flat response in the wide energy range up to 20 MeV while being downsized by one fifth compared with long counters. The positions of the effective center were determined as a function of the neutron energy. We also proposed a method to evaluate the neutron energy using the detector, which will allow various new applications by taking advantage of measuring the neutron fluence and energy at the same time.

show abstract

Calibration of the NPL standard Ra-Be photoneutron sources by an improved manganese sulphate bath technique

Cited by 36 publications

References 11 publications

Development of a Compact Flat Response Neutron Detector

Development of a Compact Flat Response Neutron Detector

An absolute determination of the 235U fission cross section at 964 keV

Development of a compact flat response neutron detector

Contact Info

Product

Resources

About