ae ques Project 4.2 - Thermal Burns - Capt A. R. 4 —t-- Behnke, a a Jr. - NRDL I have a very modest proposal —- I'm not going to bring out Noah's Ark with all the animals on it - I can't top Dr. Brown, I'm just going to bring out a few rats, if possible. The objectives of 4.2 are to ascertain the thermal radiant effects from Mt weapons on rats! skin as a basis for casualty estimation. Since the key personnel in this great show with its three main events running simultaneously are justifiably, and rightly so, physicists, chemists and engineers, and since the biclogist generally has only a nuisance value, I'll say a few words of justification for this work. Since the epidermis of the rat's skin is less than a millimeter in thickness, what we're interested in is the critical radiant thermal energy necessary to cause a thirddegree burn. Now the rat's skin, that is the reactions of the properly prepared rat's skin are similar to those of human skin, so I don't think we can argue that port at all. Why conduct a field test? Why not just stay in the laboratory where we belong? Here's the reason. If we consider the critical eergy necessary to produce such burns, then the radiant energy from a source, depending upon the wave-length band (extending from 0.3 micron to higher wave-lengths) at which the energy is transmitted, depends upon the total amount of energy in terms of calories - the true value necessary to destroy the tissue. For example, in this region of the spectrum, about four calories total energy are required to cause the destruction; and in the long-wave portion of the spectrum, about the same value; but in here, in what Dr. Plum terms the "window", about 28 calories are required. The reason is that in this portion of the spectrum, energy instead of being absorbed is reflected and transmitted, and since only one or two calories difference is the difference between a first and third-degree burn injury, and since with reference to the Mt weapon, this spectrum is changed during the event of the thermal pulse, and since the thermal pulse is much longer than with the kt weapon, it is necessary for the biologist to ask for a field test to determine this critical value. Background, briefly: In Operation BUSTER-JANGLE, in 1951, it was determined that because of the short duration of the thermal pulse in the kt weapon, and because it was known that the spectrum is relatively constant over the short time period, it was determined that a carbon-arec searchlight in the laboratory simulated rather precisely the field source of energy. However, this is not true with the Mt weapon. What is the experimental procedure? Briefly, it is this I may say with reference to the kt weapon, the "Q" value was approximately seven calories - maybe a little less. In the Mt weapon, it is expected that this value will be in the order of 15 calories since much of the energy is transmitted in this region, the red region of the thermal spectrum. With reference to the experimental set-up, it is proposed on shot Cherokee, to establish an experimental phase on George, a distance of eight miles - and there Dr, Plum will. have the calorimeters and the radiometers and the physical set-up without which we are lost, to make the necessary measurements. And on George we expect to get at the high level, about 30 calories total of thermal pulse and then, by means of attenuating there, to get a distribution of energy down to about five calories, so - bo yl ee =