抄録
Authors attemped to measure the lead equivalent of various kind of the x-ray protective barrier through the estimation of leakage doses by the use of a dosemeter, in order to control the radiation hazard.
A 70 KVp, 3mA and 50cm of focal distance of portable x-ray generator was generally used. 15 plates of various kind of thickness in the lead plates, cement plates mortared and Barrait plates mortared were appreciated as a protective barrier.
Results were as follows;
1) A 1.0mm of lead equivalent could be measured by the dosemeter, provided that the tube voltage of x-ray generator was about 70 kilovolts.
2) When the tube voltage was 70 KVp, a 0.3mm -thick of lead plate showed 1600-1850mR/hr. of the leakage doses measured by the dosemeter, 310-400mR/hr. to 0.5mm, 70-95mR/hr. to 0.8mm and 17-32mR/hr. to 1.0mm, respectively,
3) A 5cm of thickness of cement plate mortared consisted from 1:1 of sand and cement quantitatively, showed the same effect as the 0.3-0.5mm of lead equivalent, and a 10cm of these about 1.0mm of one.
4) A 2.5cm of thickness of Barrait plate mortared which constituted with 5kg/3.3m2 of Barrait substance, revealed the same effect as the 0.1mm of lead equivalent. Moreover, these plate with 20kg/3.3m2 of Barrait substance showed about 0.5mm and that with 40 kg/3.3m2 of one about 1.0mm of lead equivalent, respectively.
