Hotes on Mtg, 25 Aug '51 bomb itself acting as a converter and with collimators to look at three sections of the bomb, One might want to use an energy-sensitive detector. While it would give mich joy to get both a's, the feeling at the moment ie that the attenuation in the case is probably too great to follow a on the second bomb in anything corresponding to a constant @ region. one could see it, emer FFne This is not completely clear, however} for example, if one were willing to put a large collimator and shield right next to the bomb, conceivably (According to Teller, there is a chance that some of the sections will not be so heavy as in the original design, thus perhaps lessening the problems of attenuation.) On the basis of predicted pressures and gamma intensities, it appears that e recording shelter would be feasible at~ 2500 - 3000 yids; this would have to be a stronger structure and with more gamma-ray shielding than in the past, but not orders of magnitude different. There ida also the possibility that a remote recording scheme, using relay The question of cable attenuation has ERAERES upper we stations, will be ready in time. yet to be looked into--it is conceivable that even at 2500 - 3000 yds and with a large initial signal, amplifiers would be necessary. (Since the resolving times ve are interested in here would be very mich less, this may not be a serious difficulty.) will also be a problen. Recovery of film from a close station ‘(Beller agreed that a from the first bomb would beinteresting, DELETED ee er Be. e ~ but if one uses TK-5, for example, we already know its a.’ DELETE, DELETED ™ Internal Threshold Detectors 3 As in the past, it is hoped to obtain an efficiency determination by radiochemical analysis of cloud samples collected by aircraft. While the difficulties may be quite serious for a super situation, as discussed below, the method is nevertheless a powerful one which will Bite location has a bearing on the experimen: only with regard (1) provision for reasonably situated take-off and landing bases for the sampling aircraft (a condition not hard to satisfy for almost any site or mode of operation); (2) composition of the soil or other media in connection with contamination in the sample. The most serious difficulty as regards ea super is that of collecting a sample containing an adequate fraction of the bomb from a device which blows itself apart so well. Another difficulty is, of course, _ the well-known one that the isotopes produced by the reaction then undergo an (n,7) process so that the errors in determining amount of burn-up become extremely large. eee tos . ee oe almost certainly be employed.

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