Fast-neutron and gamma-ray dose rates within 4-ft-diam, 20-ftdeep, concrete-lined holes have been measured at the ORNL Tower Shielding Facility. The radiation source was the Tower Shielding Reactor II (TSR-II) enclosed in a shield which modified the neutron to gamma-ray ratio of the reactor leakage spectrum to more closely resemble that of a weapon spectrum. The holes were located at horizontal distances of 100, 228, and 450 ft from the reactor. From the hole at 100 ft extended a reinforced concrete-lined tunnel, 6 ft high, 2 1/2 ft wide, and 20 ft long,with its ceiling 10 ft below ground level. The experimental measurements consisted of vertical traverses in the three holes and horizontal traverses in the tunnel. The parameters varied included distance from the reactor, the angle of elevation of the reactor with respect to the horizontal at the hole, and the material and thickness of the shield over the hole. Reactor elevation angles ranged from 15 to 90°. The shields over the holes were concrete, iron, and laminated iron and concrete slabs.

No abstract

The ratios of the mean bone-marrow dose and of the midline abdomen dose to the corresponding exposures were measured for a phantom exposed in a rotational geometry about its vertical axis to broad beams of X-and y-radiation incident at angles from -30' to +75O to the normal to the axis of rotation. The energy of the radiation varied from 0.06 to 0.66 MeV. The ratio of the dose to the exposure was heavily dependent on the irradiation geometry. For many exposure conditions it was shown that the ratio of dose to exposure obtained at normal incidence would not be sufficient to assess the hazard for acute effects of whole-body irradiation.

No abstract

No abstract