Journal of Nuclear Science, Engineering and Technology (JONSAT)
In cooperation with the Iranian Nuclear Society

Absolute activity of gold foil measurement using coincidence method to determine absolute neutron flux of zero power reactor

Document Type : Research Paper

Authors

P Kaviani
N Tehrani
https://doi.org/10.24200/nst.2019.1035
Abstract
To perform an effective experimental implementation in a zero- power reactor or more generally, critical assemblies, it is necessary to measure the total neutron flux to calibrate the reactor power. The 4πβ-γ coincidence method via the activation of gold foil is a well known standard method for absolute neutron flux measurements. The absolute neutron flux is obtained by measuring the absolute activity of the irradiated gold foil, ranged in 102-104 Bq. In this method, the gold foil is irradiated at the desired position. The beta, gamma, and the coincidence rates are by using the 4πβ-γ coincidence system, and the absolute activity of gold foil is then obtained. The β-γ rays emitted from the irradiated gold foil are recorded in a concise period of tim (of the order 10-8 seconds). The advantage of this method is that the efficiency of either detector is directly dependent on the counting rates. Changing the beta detector efficiency due to the high voltage change and then measuring  the beta, gamma, and coincidence counting rates, the plot of beta counting rates against the beta detector efficiencies can be introduced. By extrapolating the efficiencies to a unit value, the absolute activity of the gold foil can be obtained.

Highlights

  1. J.F. RAFFLE, DETERMINATION OF ABSOLUTE NEUTRON FLUX BY GOLD ACTIVATION, J. NUCL. ENERGY, Part A: Reactor Science. 10, 8 (1959).
  2. P.J. CAMPION, The Standardisation of Radioisotopes by the Beta-Gamma Coincidence Method Using High Efficiency Detectors, (Nuclear Physics Branch Atomic Energy of Canada, 1958).
  3. J. THOMAS, THEORETICAL ANALYSIS OF THE 4πβ-γ COINCIDENCE METHOD, PHYSICS LABORATORY I, TECHNICAL UNIVERSITY OF DENMARK.
  4. Y. Gao, D. Hu, 4µβ-γ coincidence equipment installation and commissioning program, (1993).
  5. H. MENKE, ABSOLUTE COUNTING OF THICKSOURCES BY THE 4πβ-γ COINCIDENCE METHOD, (Mainz, Germany, 1960).
  6. J. BARNOTHY, Coincidence Methods of Measuring Disintegration Rate of Radioactive Sources, The Review of Scientific Instruments. 2, 415 (1950).
  7. J.P. PEROLAT, SOME SPECIAL PROBLEMS IN COINCIDENCE MEASUREMENT, NULEAR INSTRUMENTS AND METHODS. 12, 143 (1973).
  8. A.P. BAERG, THE EFFICIENCY EXTRAPOLATION METHOD IN COINCIDENCE CONTING, NULEAR INSTRUMENTS AND METHODS.12, 179 (1973).
  9. Y. Gao, Absolute Neutron Flux Measuerement Technique and Data Processing Code, THECHNICAL TRANSFER DOCUMENT, (1993).
  10. P. Kaviani, N. Tehrani, M. Moubed, Basic of Absolute Activity Calculation by Coincidence Method, Esfahan Nuclear Technology Center, (1998).
  11. Y. GAO, 4πβ-γ COINCIDENCE SYSTEM, OPERATION GUIDE, (China Institute of Atomic Energy,1993).
  12. P.J. CAMPION, Int. J. Appl. Rad. Isotopes. 4, 232 (1959).

Keywords

Absolute neutron flux
Absolute activity
Coincidence method
Gold foil
  1. J.F. RAFFLE, DETERMINATION OF ABSOLUTE NEUTRON FLUX BY GOLD ACTIVATION, J. NUCL. ENERGY, Part A: Reactor Science. 10, 8 (1959).
  2. P.J. CAMPION, The Standardisation of Radioisotopes by the Beta-Gamma Coincidence Method Using High Efficiency Detectors, (Nuclear Physics Branch Atomic Energy of Canada, 1958).
  3. J. THOMAS, THEORETICAL ANALYSIS OF THE 4πβ-γ COINCIDENCE METHOD, PHYSICS LABORATORY I, TECHNICAL UNIVERSITY OF DENMARK.
  4. Y. Gao, D. Hu, 4µβ-γ coincidence equipment installation and commissioning program, (1993).
  5. H. MENKE, ABSOLUTE COUNTING OF THICKSOURCES BY THE 4πβ-γ COINCIDENCE METHOD, (Mainz, Germany, 1960).
  6. J. BARNOTHY, Coincidence Methods of Measuring Disintegration Rate of Radioactive Sources, The Review of Scientific Instruments. 2, 415 (1950).
  7. J.P. PEROLAT, SOME SPECIAL PROBLEMS IN COINCIDENCE MEASUREMENT, NULEAR INSTRUMENTS AND METHODS. 12, 143 (1973).
  8. A.P. BAERG, THE EFFICIENCY EXTRAPOLATION METHOD IN COINCIDENCE CONTING, NULEAR INSTRUMENTS AND METHODS.12, 179 (1973).
  9. Y. Gao, Absolute Neutron Flux Measuerement Technique and Data Processing Code, THECHNICAL TRANSFER DOCUMENT, (1993).
  10. P. Kaviani, N. Tehrani, M. Moubed, Basic of Absolute Activity Calculation by Coincidence Method, Esfahan Nuclear Technology Center, (1998).
  11. Y. GAO, 4πβ-γ COINCIDENCE SYSTEM, OPERATION GUIDE, (China Institute of Atomic Energy,1993).
  12. P.J. CAMPION, Int. J. Appl. Rad. Isotopes. 4, 232 (1959).
Journal of Nuclear Science, Engineering and Technology (JONSAT)
Volume 40, Issue 3 - Serial Number 89
December 2019
Pages 152-158

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