geCa fe og Project 15.2 > J-15 Photography (YEN Speed Photography) - Gaelen Felt - LASL We are concerned with the very early stage of photography. The work that I am going to describe a little bit is going to be done by the LASL photophysics group. Our main instruments are all very similar - they are rotating mirror cameras. There are three main types; one is a framing camera, which, depending on the type of turbine we put in it, will take pictures at rates of 3,500,000 per second or approximately 7,000,000 per second. The recycling time is rather short and we don't end up with very many pictures, but the rate is very high. The other two types of cameras are streak cameras and sweeping image cameras. The Model 100 streak camera will write on the film with a speed of about 15-mm per microsecond. It can resolve approximately 10°™ seconds. The other camera, the LASL Model 103, @ sweeping image camera is at present in the design stages; we haven't built any of them yet. Its theoretical limit in time resolution is 5 x 10-1 - We don't really think it is going to do quite that well, but if it will do 1079 seconds it is perfectly satisfactory for the type of work we are trying to do. We will operate three major instrument etations, one of them gnthe Island of _ Teiteirpucchi, which is up near Bogairikk - I guess that's Helen. ° RELETED DELETED DELETED wigge: The work that we are doing in these buildings falls into two main categories. The first category is diagnostic experiments where the intent is to obtain information on the behavior of the device being fired, for use in the analysis of the device itself - how it works. There are small variations in the type of information we are looking for. In all cases, we are dealing with very short time intervals. In the Bikini group, these are all large devices; there the main piece of information we are after is the interval between reactions, the so-called time interval measurement which we have done before. I guess the first time we did this was on Mike. We are also interested in the very early growth of the fireball during the radiation phase. In particular, we are interested in the first three, four or five microseconds. The reason for this is that we think these measurements can help in separating out the yields. If there is more than one yield, as in the two-stage devices, we can tell something about the yield of the primary stage. At Eniwetok, some of the work is diagnostic but the main effort is not. It is @ continuation of the work that we have been doing for several years. Those of you who were in Nevada this time may recall the experiment we did there, in which we had the 500' vacuum pipes on the Apple 2 tower. The information here is research information - it is not connected with the device at all.’ It is using the device as @ source of energy for the experiment. =