Philippine Journal of Science
149 (S1): 93-99, Special Issue on Nuclear S&T
ISSN 0031 – 7683
Date Received: 17 Jun 2019

 

Experimental, Computational, and Analytical Methods
for the Characterization of a Neutron Field for Calibration
of Neutron Monitoring Instruments in the Philippines

 

Marianna Lourdes Marie L. Grande¹*, Frederick C. Hila²,
Ave Ann Nikolle M. Garalde1, Christy Mae T. Betos¹,
Cheri Anne M. Dingle², and Kristine Marie D. Romallosa¹

 

¹Nuclear Services Division, ²Atomic Research Division
Department of Science and Technology – Philippine Nuclear Research Institute
(DOST-PNRI), Quezon City 1101 Philippines

 

*Corresponding author: mlgrande@pnri.dost.gov.ph

 

[Download]
Grande MLM et al. 2020. Experimental, Computational, and Analytical Methods
for the Characterization of a Neutron Field for Calibration of Neutron Monitoring Instruments in the Philippines. Philipp J Sci 149(S1): 93–99.
https://doi.org/10.56899/149.S1.11

 

 

ABSTRACT

Despite the many emerging applications of neutron radiation in the Philippines, there is a gap in the country’s capability to calibrate neutron radiation monitoring instruments that are necessary for measuring the radiation hazards in the workplace. In this study, the neutron field of a bare Californium-252 source was characterized and established for calibration of radiation monitoring instruments. The fluence rate of the neutron field was experimentally characterized using the shadow cone method, and the results were compared with Monte Carlo simulations and analytical methods. The neutron fluence rate of the neutron source with a nominal activity of 200 MBq was measured at distances of 100 cm, 130 cm, and 150 cm with a reference He-3 spherical proportional counter in a Bonner sphere. The measured fluences were found to be φ100 = 151.09 cm–2s–1, φ130 = 89.13 cm–2s–1, and φ150 = 67.31 cm–2s–1, respectively. Results also show that the experimental values are agreeable with the computational and analytical methods to within 10%. The characterized neutron field is the first of its kind in the Philippines, and can now be used for calibrating neutron radiation monitoring instruments. This study will, therefore, help improve the accuracy of radiation measurements and support the radiation protection program of neutron facilities in the country.