Characterization of neutron calibration fields at the TINT's 50 Ci americium-241/beryllium neutron irradiator

Toprak Nem İçeriğinin İzlenmesi ve Tayininde Kullanılan Yöntemler

“…Nötronmetrelerdeki radyoaktif kaynak genellikle Amerikyum-241/Berilyum (Am/Be) karışımı bir maddeden oluşur. Amerikyum-241/Berilyum nötron saçan bir kaynaktır ve ziraat dışında; petrol mühendisliği ve endüstri gibi sektörlerde kullanılır [36]. Bu radyoaktif kaynağa sahip nötron prob çakılan tüplerin içinden ölçülmek istenen derinliğe kadar sarkıtılır.…”

Investigation of the response characteristics of OSL albedo neutron dosimeters in a241AmBe reference neutron field

“…For each batch, 4 OSLN dosimeters were placed on a water phantom (30 cm width × 30 cm height × 15 cm thick) facing the center of the neutron beam, as shown in Figure 3. The reference neutron field was produced by TINT's 50 Ci 241 AmBe neutron irradiator [1]. Neutron irradiation was done at 100 cm distance from the source with the rectangular beam of 26.7 cm x 26.7 cm and the beam homogeneity of 10.6% (standard deviation of the average neutron dose equivalent rate of the field).…”

“…Neutron irradiation was done at 100 cm distance from the source with the rectangular beam of 26.7 cm x 26.7 cm and the beam homogeneity of 10.6% (standard deviation of the average neutron dose equivalent rate of the field). H p (10) for neutrons at the irradiation position was determined to be 2,102 μSv/h, based on Monte Carlo simulation and measurement with a moderated neutron spectrometer [1], with the agreement of 13% between both methods. To test the accuracy of evaluated values, 3 batches of the OSLN dosimeters were irradiated with ~1-3 mSv neutrons.…”

“…Batch homogeneity = (E max -E min )/E max (1) where E max and E min are the maximum and minimum evaluated values of each batch. The batch homogeneity should not exceed 0.3 [2].…”

“…The OSL dosimeters are regularly tested in reference photon fields to ensure reliable photon dose equivalent evaluation, while type testing of the dosimeters in reference neutron fields could not be conveniently done in the past due to a lack of neutron reference fields in Thailand. Until recently, TINT has set up a radioactive neutron irradiator for generating neutron reference fields for detector testing and research purposes [1], making it possible to test the performance and reliability of the OSL dosimeters for neutron dose equivalent evaluation.…”