132 THE SHORTER-TERM BIOLOGICAL HAZARDS OF A FALLOUT FIELD With regard to (A) above, acceptance “on faith” has manyprecedents andis not, per se, undesirable. The difficulty is that a lack of understanding of dosimetry often has a curiously ennervating effect on the biologist doing radiation hazard work. He begins to feel that all he does is feed the mice and count the number dead at the end of 30 days. Someone else does the brainwork. Consequently, he drifts MATHEMATICAL AIDS IN UNDERSTANDING OF BIOLOGICAL HAZARDS 4. Wurrz, Guavys: “Iixperiment with Co Gamma Rays in Water,” Phystcad Review (78} 330 (A} (1950). 5, Parxwr, H. M.: “Some Physical Aspects of Beta Radiation on Tissue"; CH-930, 6. Spencer, L. V., “Theory of Electron Penetration”; Physteal Review [98], 1597 (1955). 7. Roesca, W. C.: “Age Diffusion Theory for Beta Ray Problems,” HW-32121—Hanford Atomic Products Operation, Richland, Washington. off into some other field of endeavor. Carcerwise this is probsbly a sound instinct as far as DISCUSSION the biologist is concerned; but if the proper James T. Brennan condition of national survival (as some say), then the necessary minimum of capable bicl- Col. Brennan. I should like to stop here and give the people in the audience who have solution of the fallout problem is, potentially, a ogists and physicians must be kept in the effort. One positive step that any biologist can take is to meke a renewed attempt to understand the mathematics involved. Even the “crude” methods discussed earlier provide a degree of understanding that can be had in no easier way. With regard to (B) above, it is offered as one opinion that, in order to arrive at a complete knowledge of other mathematical efforts that are relevant a chance to please stand up and mention them, and indicate what application and significance they have to the hazard problem. I know of several. I know Naval Radiologi- cal Defense Laboratory has direction measure- ments on it. They are trying to get the theory to go with it. I know Mr. Joseph Lindwarm medical policy regarding a fallout hazard, itwill ultimately be necessary not only to calculate has mathematicians hitting that direction. also to: Bureau of Standards, who have by far the and measure total beta and gamma fluxes, but (1) Calculate and measure the polar distribution(i. e., direction) of those fluxesinair. (2) Calculate and measure beta and gamma depth dose in humansized animalsin a fallout field. If this seems to be asking a great deal, then it should be recalled that the problem is impor- tant enough to warrant the use of whatever scientific resources are necessary to solve it completely. REFERENCES 1. Personal communication, Reproduced herein. 2. Conprr, R. L, Dyson, J. P., and Lama, W, A. 8.: “An Estimate of the Relative Hazard of Beta and Gamma Radiation from Fission Products”; USNRDL 95--(H), April 1949. 3. Operation Greenhouse: 3.1.5 Memorandum J. T. | Brennan to G. W. MecDonnel, “Beta Hazard in Bomb Test Areas,” May 1951. I today have been informed that the National greatest resources in this matter have under consideration a general treatment of beta ray penetration. They will come out with a gen- eral theory. Whether or not this includes direction, I don’t know. I wonder if I could ask the gentleman from the Bureau of Stand- ards, Dr. Wyckoff, to say a word aboutthat. Dr. Wrcnorr. I relayed the few notes I had from Dr. Spencer, but I amafraid I don’t have anything to add other than the fact that they have coded up some of the beta penetration problems for the Standards Eastern Automatic Computer and apparently are able to put in the spectra of beta particles going into a shielding situation, and will be able to obtain both the dose distribution in the shielding and the flux coming out. I don’t know if that includes the angular distribution that you are interested in. Col. Brennan. The theory for gammarays on the other hand I do know does permit caleu- 133 lations of polar distribution. It would perhaps be an enormous job and extended effort in radiation dose in terms of rep to the roentgen. I might say that we discussed there this mathe- that could be used for a simple situation by pointed out the fact that you do have variation applied mathematics to reduce this to tables simple people for such things as a foxhole. This is a goal worth striving for, and T think one well worth financing. A good mathe- matical theory climinates a lot of bad experiments, and makes it certain that money will never be wasted. Mathematics is about the cheapest type of research you can do, J believe, in return for dollar expended. This is about all the ground I wanted to cover with respect to how mathematics has been applied and mightbe applied to the resid- matical treatment for the gamma and also in the dose duc to the variation in energy with time, I don’t think Dr. Brennan pointed this out. However, I think it is obvious when you try to go from the equation to the determina- tion of dose rate that you would need the actual gamma energy there to determine this. That does change with time. We discussed this particular thing in these papers that we wrote up, and also the fact thet your beta to gamma-—-that is beta particle to Particularly, does anyone know gamma photon—ratio will change with time. As a matter of fact, if you calculate the beta to gamma ratio for time about 2 to 3 years you to measure the angular distribution of gamma Therefore, going back te the simplest relationship, 2 times 75, that would be 8 times 75. ual problem. or comments? Are there any further questions of mathematical efforts thatare relevant? Capt. Zerumer (School of Aviation Medicine). J believe there are efforts being directed andneutrons, atleast, in the forthcomingfield test, using columnators with solid angles trying to obtain the angular distribution in the hemisphere. Sol. Brennan. residual? Capt. Zetumer. Is this prompt radiation or Prompt. I imagine there will be some delayed and scattered radiation also, and some immediate fallout, because they won't be able to get to the columnators for at will find that there will be about 8 beta particles to a gamma photon. This is approximate. So that for very long times after detonation, you will get or should get tremendous ratios of beta rep to gamma roentgen. I think that is about all I wouldlike to discuss al the present time. Col. Brennan. Thank you very much, Dr. Teresi. The British have emphasized this. I omitted to say that these calculations do not apply ex- cept at times between the beta-gamma ratio is least. two hours. Col. Brennan, We might have a word from NRDL. 1 know they have a definite interest British articles. Have you seen them? Dr. Teresr. Yes. subject of the beta to gammaratios, both the beta particles to gammaphotons, and the beta factor of about four. They had a report in which they had measurements which support this. in this activity. Dr. Terest (NRDL). We wrote about two or three technical memorandaonthis particular two particles per photon. There are two Col. Brennan. They emphasize the fact that after one year the beta goed up by a