28 FREILING, CROCKER, AND ADAMS simply. Similarly, a response curve for an instrument can be substituted. We have calculated the response ofthe NRDL 47 ionization cham- ber,*! by using the response curves of Report USNRDL-TR-155. Results A forthcoming USNRDL technical report will list the predicted radiological properties of unfractionated debris for seven important cases: 2351), thermal neutrons 2351) fission-spectrum neutrons 35) high-energy neutrons 2331) fission-spectrum neutrons *39Du, fission-spectrum neutrons 2381] fission-spectrum neutrons 2381] thermonuclear neutrons Twenty-nine time points, ranging from 1 hr to 70 years, were requested from the computer. The output for 24 hr is analyzed to pro- duce gamma-photon emission spectra from 0 to 4.0 Mev in 0.100-Mev increments. At each time point total disintegration rates and dose rates, together with individual nuclide contributions (when these amount to 1% or more of the total), are itemized. In addition, total ionization currents and individual nuclide contributions are listed for thermal neutron fission of *UY. The output is far too voluminous to give more than a sample here. We will therefore restrict further discussion to the most important case, that of 7°°U fission with a thermonuclear neutron spec- trum. The total activity in disintegrations per second is shown in Fig. 10. The individual activities have been plotted in Fig. 11 as relative values (percents of total activity) against time in the manner of Hunter and Ballou. Two points are worth mentioning here about the effect of neutron energy on the activities after 1 hr. The nuclides ‘Sb and '’Te, which do not appear for *u thermal fission, do appear in the present case. This is due to an increase in chain yield. Note that relative-activity curves for several nuclides in the hours and days ranges have been omitted from Fig. 11 in the interest of legibility. The gamma-photon spectra at 6 hr, 7 days, and 270 days are shown in Fig. 12 as composite histograms. These show general order of magnitude agreement with Bjornerstedt’s predictions, *” but a detailed reconciliation remains to be made. Figure 13 shows the gross exposure-dose rate for gamma radiation at 3 ft above an infinite plane uniformly contaminated with 10! fis- sions/cm’.