Interview with Charles E. Violet, May 22, 2004

Nevada Test Site Oral History Project University of Nevada, Las Vegas Interview with Charles E. Violet May 22, 2004 Danville, California Interview Conducted By Mary Palevsky © 2007 by UNLV Libraries Oral history is a method of collecting historical information through recorded interviews conducted by an interviewer/ researcher with an interviewee/ narrator who possesses firsthand knowledge of historically significant events. The goal is to create an archive which adds relevant material to the existing historical record. Oral history recordings and transcripts are primary source material and do not represent the final, verified, or complete narrative of the events under discussion. Rather, oral history is a spoken remembrance or dialogue, reflecting the interviewee’s memories, points of view and personal opinions about events in response to the interviewer’s specific questions. Oral history interviews document each interviewee’s personal engagement with the history in question. They are unique records, reflecting the particular meaning the interviewee draws from her/ his individual life experience. Produced by: The Nevada Test Site Oral History Project Departments of History and Sociology University of Nevada, Las Vegas, 89154- 5020 Director and Editor Mary Palevsky Principal Investigators Robert Futrell, Dept. of Sociology Andrew Kirk, Dept. of History The material in the Nevada Test Site Oral History Project archive is based upon work supported by the U. S. Dept. of Energy under award number DEFG52- 03NV99203 and the U. S. Dept. of Education under award number P116Z040093. Any opinions, findings, and conclusions or recommendations expressed in these recordings and transcripts are those of project participants— oral history interviewees and/ or oral history interviewers— and do not necessarily reflect the views of the U. S. Department of Energy or the U. S. Department of Education. UNLV Nevada Test Site Oral History Project 1 Interview with Charles Violet May 22, 2004 Conducted by Mary Palevsky Table of Contents Introduction: Dr. Violet recalls his childhood, education, and military service during World War II. 1 After the war, Dr. Violet graduated from the University of Chicago and went on to attend graduate school at the University of California at Berkeley. 3 Upon completing his Ph. D. in physics, Dr. Violet began working at the University of California Radiation Laboratory ( later Livermore laboratory), where he conducted high- energy physics experiments. 4 Dr. Violet explains the physics behind the Fonex experiments conducted for the Castle test series. 7 Description of Bravo logistics 11 Fonex experiments had also been conducted for the Mike test on Operation Ivy, remembrances of Upshot- Knothole at the Nevada Test Site. 13 Dr. Violet describes experiencing the Bravo test and analyzing the scientific aspects of a thermonuclear reaction. 17 Fallout from the Bravo test caused concerns for radiological safety. 19 After from the Pacific, Dr. Violet began to work on underground nuclear tests, experiences during the Rainier test at the NTS. 23 Underground testing and seismology, containment of radioactive products underground, descriptions of Rainier. 26 Both scientists and hard- rock drillers had to communicate and improvise in order to perform vital scientific analysis of the first underground nuclear tests. 29 Dr. Violet discusses the test program’s safety panel which worked to ensure that the nuclear tests were safe for those both on and off of the Nevada Test Site. 31 Dr. Violet recalls the Diablo test, in which the device had to be disarmed after it failed to detonate. 34 Dr. Violet describes the focus required to conduct nuclear tests, Sputnik was launched soon after Rainier. 38 The Plowshare program involved a series of cratering tests in Alaska and elsewhere. 39 Frustrated with bureaucratic politics and the moratorium on nuclear testing, Dr. Violet left the test program. 42 The moratorium lent a new importance to the ability to use seismic data to detect the effects of clandestine underground nuclear tests, salt mine high explosives tests near Winnfield, Louisiana 44 Conclusion: Dr. Violet advised State Department officials and testified before Congress the Joint Committee on Atomic Energy ( JCAE) regarding the seismic detection of nuclear tests. 46 UNLV Nevada Test Site Oral History Project 1 Interview with Charles E. Violet May 22, 2004 in Danville, California Conducted by Mary Palevsky [ 00: 00: 00] Begin Track 2, Disk 1. Mary Palevsky: And we’re recording. Charles Violet: My name is Charles E. Violet, sometimes known as Chuck Violet. I was born in Des Moines, Iowa in 1924. My family moved to St. Louis when I was four. And they moved to Kansas City, Missouri when I was six, and then I remained there through grade school and high school. My main interests in my formative years were music. And I went to— or rather I took lessons and played the cello from about age eight and through elementary school and high school, and became fairly good at it and went to numerous music festivals which are very prominent in the Middle West and won some prizes playing cello and so forth. And then I went to junior college, Kansas City Junior College, for about a year- and- a- half. Let’s see, I graduated from high school in 1941. And at that time the war, World War [ II], in Europe was underway and it was obvious I was going to be participating soon. And so I enlisted in the U. S. Army and I was inducted in Fort Leavenworth, Kansas in March 1943 at age eighteen. And I then later transferred to the U. S. Army Air Forces and entered a program which is called pre- meteorology, and the objective of that or the end point of that would be I would become a meteorology cadet in the Air Force and graduate and become a second lieutenant and be assigned to an operational unit as a meteorologist, air force meteorologist. Going back for a minute, I think my main interest in my young life, formative years, was music, and if the war hadn’t come along I might well have progressed to become a musician. But UNLV Nevada Test Site Oral History Project 2 the war changed that. And also one of my interests was sports— baseball and football— but I was not very good at it, so I just played at sandlot games and so forth. Anyway, I became interested in science really as a result of the war and realizing that I would like to— I knew I was going to be involved in the armed forces some way or other and I would like to be involved as a technical person rather than as a private in the infantry. So I did go to University of Chicago in their pre- meteorology program. That was in 1943. And then I finished that course. And by the time we finished, the Air Force decided [ 00: 05: 00] they didn’t need us— or some of us— so we were given several options. And I became an air force communications cadet, and we studied basic electronics and so forth and then studied all the communications equipment in the Air Force. And then later I went to radar school in Florida, Boca Raton Field in Florida, and studied radar. And by that time it was— well, when I was at Boca Raton in the summer of ‘ 45 is when we dropped the bomb on Hiroshima. So I had fully expected to go to the Pacific, but the war in the Pacific ended at the time that I was finishing up my training in radar. And a lot of other things changed. As it turns out, I was shipped to Europe, and went by troop ship to Europe and then by train to Berlin. And that was all very interesting, riding a train at that point in time through France and Germany. The train threaded its way through much destruction and much damage and it was like a single line that was going most of the way through a circuitous route from Paris to— actually we went from Paris to Munich and stayed at a Luftwaffe field outside Munich and stayed in some very nice barracks which fortunately our air force declined to bomb during the war, so they were very nice facilities. And at that time the Dachau trial was going on— war criminal trial— and I could’ve gone and I didn’t. And I’ve always regretted that I never went to that trial. I mean, it was continuing UNLV Nevada Test Site Oral History Project 3 over a period of time and I did hear comments from my associates, my colleagues, my brothers- in- arms, about some of the things they heard and listened to. And I’ve always regretted not going to it. Anyway, I then traveled up to Berlin and I was stationed at the Tempelhof Aerodrome as communications officer for the Ninth Air Force and also an organization calls EATS, which is European Air Transport System. So after a year I came back. I opted to leave the Air Force. In fact, I was very happy to leave the Air Force. And I started my attendance at the University of Chicago in the fall of 1946. And I spent one year in the college of the university and got a Ph. B. That’s a Bachelor of Philosophy, which I don’t know if any other university gives that or not. And then I majored in meteorology because I at that time was very interested in science and math. And so one year later— no, let’s see, two years later— I got an S. B. from Chicago, University of Chicago, in meteorology. But by that time I became interested in physics, so I transferred. I wanted to go into graduate school in physics at [ the University of California at] Berkeley, so I transferred out to Berkeley. I had to spend one year as an undergraduate to make up my deficit in physics courses, and then entered graduate school in 1950. Was it ‘ 50 or ‘ 51? I think it was ‘ 51, excuse me. Nineteen fifty- one. And then I got a Ph. D. in 1953 in high energy physics. Who were some of your professors there? Who was there at that time? [ 00: 10: 00] Well, a notable person that wasn’t there was [ J. Robert] Oppenheimer. He had left Berkeley, but his presence was still felt. And there were lecture notes of Oppenheimer that were available to students, mimeographed I guess you’d say at that time. And so that was highly disappointing. Although I did have a course from [ Edward] Teller when I was at the University UNLV Nevada Test Site Oral History Project 4 of Chicago, in beginning physics. That was very good. And I did actually see [ Enrico] Fermi one time at a lecture he gave, and he was there at that time. When I was in Chicago as a cadet studying meteorology, we would go to Stagg Field for physical education. And we noticed that there was a certain area of Stagg Field that was something strange happened every now and then. Somebody would come out, a young man would come out with a piece of metal and hoist it up on some kind of pulley to a high level and then trigger it and it would drop and fall to the ground. And none of us knew what that was, and to this day I don’t know what was going on, although we commented about it. But that was the location where the first nuclear pile was built. And so I’ll never know what the— I’ve often wondered if it was a subterfuge to confuse spies or whatever, but who knows? Anyway, let’s see, the people who were quite notable then was Edwin McMillan and [ Emilio] Segrè and [ Luis] Alvarez. And I took a course from Alvarez in nuclear physics; that was very good. That was really— he’s very remarkable, very good teacher. Let’s see, other notable people. That’s all I can think of at the moment. That’s fine. Well, let’s see. So after I got my Ph. D. I went— well, I’ll backtrack a minute. Before I got my Ph. D., as a graduate student I met Eileen and I was married in 1951. In ’ 53, after getting my Ph. D., I took a job at Lawrence Livermore lab. At that time the name was UCRL, University of California Radiation Laboratory, and then it had several other names in between, but it’s now of course LLNL [ Lawrence Livermore National Laboratory]. I joined the testing group at the Livermore lab when I got out there, and the general testing area at that time was under Art Hudgins, and he was the person that hired me. I’ll backtrack for a minute. My graduate work, the academic part of it of course was on the campus; UNLV Nevada Test Site Oral History Project 5 the experimental part of it was at the laboratory on the hill. And there I worked in the area of nuclear track emulsions as applied to high energy physics. And my immediate supervisor was [ 00: 15: 00] Walter Barkas who was head of the film group there, and he and his group had done a lot of work already in high energy physics and studied mesons and mu- mesons and pi- mesons. And there was a famous man there from Brazil named [ C. M. G.] Lattes, who was at the time credited with— well, he and his group, he was part of Barkas’s group, discovering— I’m sorry, I’m not sure, a mu- meson or a pi- meson, I’m not sure what. But anyway, my study was high energy electron and positron interactions in material. And that was done by exposing nuclear track emulsions, electron sensitive emulsions— which had just been invented— to high energy electrons and positrons which we were produced at the synchrotron. And so we had a setup where we had a target and an arrangement which had a target and positions for the emulsions, and we had the use of a high- field magnet which we could separate out the positrons and electrons. And so we used that machine, a converter target, to convert the high energy gammas into electron- positron pairs, and then we could expose plates, either electrons or positrons. So then I could study the interactions of high energy electrons in material, namely in nuclear emulsion, which of course consisted of a number of elements— besides gelatin it had silver. And various interactions could be studied by way of the microscopes and looking at— well, looking at the emulsions with microscopes, high magnifying microscopes. So I observed many interesting interactions: electron scattering, electron- nuclear scattering, the pair production from high energy gammas in the emulsion itself. And that was mainly my work for the Ph. D. UNLV Nevada Test Site Oral History Project 6 Let’s see. Steve Whitewas a member of Barkas’s group, and Al Oliver, was— well, Steve was a physicist and Al Oliver was a technician. He was a photographic technician, very good photographic technician. About the time I got my Ph. D., the laboratory in Livermore was being formed. I think it was the previous fall, in ‘ 52, and I got my degree in ‘ 53. There was a group from the hill— I think probably under Herb York— and there were a number of other people, like Art Hudginsand I don’t know who else, went to the Pacific for the Ivy test. And they did some kind of radiation work at that test as a separate group, as part of the task group and Los Alamos [ National Laboratory] structure. Oh, Duane Sewell was part of that group, and they were the group mainly that [ 00: 20: 00] started— other than Teller, of course— that started the lab in Livermore. Am I going too far already, or should I keep going? No, no, this is great. This is great. OK. So I was hired by Art Hudgins to join Steve White’s group— Steve White and Al Oliver. Of course I knew Steve and I had talked to him about it before. And then shortly after I became a part of that group, another physicist, Chuck Francis, who I knew, we worked together in the film group in Berkeley, and he came out and joined the group. So we had this nuclear film group, and when you have a nuclear films group and experiments going on, you always have to have a number of people who are willing to sit down and scan track, which means sitting for quite a while during the day and looking through a microscope. Well, in Berkeley these people were usually graduate students, scanners. In Livermore they were housewives. And so we had to train them to scan tracks, and that means optically following a track that enters the emulsion by moving the X- Y stage on the microscope UNLV Nevada Test Site Oral History Project 7 and then looking at what happens to it. If it interacts in the emulsion, then you would form certain measurements and that’s a good event to record. So our work there involved training— well, they were usually young women that were doing this as a part of the job. The rest of her job was being a housewife. And not only training them but also supervising them, checking their work to see how they were doing, and the two sort of merged mostly. And then analyzing the data and going through whatever computations, et cetera, that this analysis required. And then we published papers about some at Livermore, with the understanding— as Steve Whitetold me, and Art Hudgins— that I could spend up to half time working on high energy physics at Berkeley. At that time the Bevatron was about ready to come on line, so I’m looking forward to doing experiments with these high- energy particles. It was quite interesting. So that was a good deal, as far as I was concerned. Interesting sideline might be that when I joined the lab, my original salary was $ 500 a month. That was in 1950. Of course, I was a graduate student.. No, wait a minute, sorry, no. That’s when I joined the lab in Livermore, my salary was $ 500 a month. As a graduate student in Berkeley, I was getting $ 125 a month. So I got quite a pay raise going to Livermore. And then after a six months’ probation, I got a fifty dollar raise. So that was very nice. But I remember when Steve White told me, in some conversation he just happened to mention that his salary was $ 700 a month. I thought, Wow, that was really something. Boy, that sounded wonderful! So my work at Livermore originally was divided into two parts: the continuing work in the high energy physics and then I started working on and planning for the Fonex experiments to be done in the Castle [ Operation Castle, 1954]. UNLV Nevada Test Site Oral History Project 8 [ 00: 25: 00] Can you explain what Fonex is? That’s something I didn’t understand from yesterday. You said Louis Rosen had invented this? Yes. Basically, you have a nuclear emulsion and the emulsion is of course made from gelatin plus silver bromide and a few other ingredients. But the emulsion has a lot of hydrogen in it, being an organic substance. So when it is exposed to neutrons, the neutrons will interact with the hydrogen or protons. And in that process the hydrogen turns into a proton— because it loses it electron— and the proton then has a velocity, a momentum, an energy, and it goes through the emulsion until it stops. And as it goes through the emulsion, it ionizes the silver bromide particles, then as light does. And so then those form virtual images, and then in the development process, the silver is converted to metallic silver and you end up with a metallic blob that can be seen optically. So this kind of a collision would be called an n, p collision, neutron- proton collision. And since they’re approximately the same mass, that’s like two billiard balls on a billiard table colliding. So we can apply— since these are low energy neutrons that we will be dealing with in terms of the fission process— we can use non- relativistic physics and calculate very simply by conservation of energy and momentum, and so forth, all the details of the collision. And so you can measure the track of the proton, and knowing the initial direction of the neutrons, then you know the angle at which the proton went off in that collision. Then you can calculate the angle of the neutron and the energy of the neutron from that collision. So it’s a technique of measuring neutron energies. So for the energies that we were interested in, namely fission neutrons— I should say neutron energy— it’s neutron energy from perhaps half a MeV up to high energies. Of course, the fission energy intensity at— well, let me backtrack. The energy that we’re interested in, at high energies, would be the 14- MeV neutrons resulting from the d, t [ deuterium- tritium] reaction in UNLV Nevada Test Site Oral History Project 9 the bomb. So from a nuclear explosive, one would expect to see— in terms of neutron energy— we would expect to see a fission spectrum, roughly speaking, a fission spectrum plus a peak for the d, t burn. Again, the d, t is a two- body collision and— well, the energy in the center mass is fourteen- point- something MeV. And then if it’s heated, if it has a high temperature, then there’s a Doppler broadening in the peak, which then gives you— instead of a sharp peak— it gives you a broad peak, depending on the temperature of the burn. And then by measuring neutron energies using nuclear emulsions, one can measure the broadening. Of [ 00: 30: 00] course, you detect a lot of 14- MeV neutrons, hopefully, and you can measure the energy distribution. And then by the broadening of the peak, you can detect the temperature of the burn, and that was the whole idea of Fonex. Right. OK. Before I leave that, just as a detail, the broadening of the peak also is a result of the experimental errors which are generally symmetric with respect to energy itself. It’s a matter of it’s a convolution process in which you extract the specific d, t temperature broadening from the total broadening, and so you have to do some physics to do that. But anyway, it can be done; it’s fairly simple. And the same thing, the same measurements, can be made with the neutron beam with neutron detectors on the long pipe, evacuated pipe, which was used in the Pacific. So, let’s see, that’s Fonex. So this was developed by Louis Rosen at Los Alamos. And Steve Whitewent to Los Alamos when he went to the lab and worked with Louis Rosen for a period of time, actually going over and looking at the films that he had received on the Mike shot. And so he came back and started up the film group of which I became a member. To do this experiment in the Pacific, of course since you’re looking at a big explosion, you had to have your detector back a ways in a bunker that will survive the explosion. And this is UNLV Nevada Test Site Oral History Project 10 true of the prompt neutron measurements also from the shot. Well, to physically get around this problem, what one does is you construct line- of- sight pipes from the device— actually from the big wall in the device building— device shack— that holds the bomb. And it’s all of course oriented properly so you have the right geometry. Then you have these pipes, these long pipes that are perhaps— I don’t know how big in diameter they were, they varied, but they were on the order of a foot in diameter, maybe down to some smaller dimension toward the device. I’m not sure. Anyway, the pipes have to be evacuated because if you leave the normally moist air that would be there— I mean, moisture makes it worse— but if you leave the air in the pipes, then the neutron attenuation over the distance you have to back off is serious. So what is done is you can start these line- of- sight pipes that are evacuated with extensive pumping systems— so they’re evacuated— and so then you don’t have any air and the neutrons can go down the pipe without being attenuated appreciably. So what I’ve said so far applies to the prompt neutron work as well as Fonex. And then eventually neutrons impinge— in the case of the neutron experiments— they impinge on the scintillators or other kinds of neutron detectors. And you have detectors, photo cells looking at the scintillators, and then you can take the signal from that and that’s your neutron intensity as a function of time. It’s a function of time because you can record the neutron intensity versus time [ 00: 35: 00] with your oscilloscopes. So with Fonex you don’t have the time ability. You take the neutrons and you essentially integrate the neutron energy over the time of the blast, over the time the neutrons were produced. And so, let’s see, our pipes ended in a block and we had a converter in the pipe, and at the position of that converter— the converter was to convert— I’ll have to backtrack here. Well, anyway, I’ll go ahead. The converter was in the pipe and it converted the neutrons to protons. The protons then took off down a second pipe, and that angle is something like 30 degrees or so, UNLV Nevada Test Site Oral History Project 11 down a second pipe, also an evacuated pipe, into a canister that held the nuclear track emulsions. The protons went through a thin window and then into the emulsion. I hasten to add here that my first description of Fonex was just one way to do it, in which the conversion of neutrons to protons took place within the emulsion. However, in this case— and Louis Rosen did this also— you can have an external hydrogenous converter, target, that will convert the neutrons there into protons. And then you can use the nuclear emulsion plates downstream at an angle from the main stream, and the protons come through a thin window and into the nuclear emulsions. And then you measure the tracks of the protons. You pick them up on the surface and measure them as they go into the emulsion. These would enter the emulsion, say, at about ten degrees from the emulsion surface, so they would go in at a glancing angle and by design they would be stopped, say, approximately halfway into the emulsion. So that was the technique used in Fonex, in this particular Fonex. They used the external target, converter, and then the protons were detected in the canister holding the nuclear track plates. Now, to prevent all the debris— that was the way to get the information from the neutrons. And of course the neutrons travel much faster than the blast, so they’re out of there. They’re ahead of the blast wave and there’s a lot of time to work with. And what kind of distances are we talking about here on these—? Well, it depends on the blast. In Castle, we were setting up to do an experiment on Morgenstern and the pipes were about, as I recall, 5,000 feet. Now, on the Los Alamos shot, the famous or infamous March 1 Los Alamos shot with Shrimp [ Castle- Bravo], the pipes were, I believe, 7,000 feet. And that’s where they discovered the fact that the line- of- sight pipes were not line- of- sight. And it was due to the fact that no one took into account the curvature of the Earth, and so they UNLV Nevada Test Site Oral History Project 12 made those adjustments. It was built by Holmes and Narver and they used standard survey techniques. They had their surveyors out there and they were looking through— it was built in sections and each section was set up, so what you had is— well, and normally surveyors don’t take into account the [ 00: 40: 00] curvature of the Earth. But at 7,000 feet, one has to. And so what you had is each section was slightly off. But it’s kind of amusing that no one ever thought of that beforehand, you know, because it wasn’t Holmes and Narver’s fault. It was— well, never mind, it doesn’t matter. Yes, that was interesting to me to hear that yesterday, that that could even happen. Yes, it was interesting to all of us out there when we heard that, you know. How come you’re only getting, you know, some fraction of what you should be seeing, you know? We couldn’t understand that. Well, anyway, our line- of- sight pipes were 5,000 feet, I think, and we had a huge array of pumps to pump on these pipes. And we had some really good mechanical technicians that were running that facility. Now, this probably seems like a really obvious question, but the pipes are running from the building that holds the weapon or the device, is the building in water or on land? Oh no, it’s on land. And so they’re running on land or under land? Yes, and they’re running on top in an array, sort of closely together, and they’re running above ground. Above ground. Yes, in a straight line above ground, and they’re built in sections and every section, there’s a place for a connection and there’s a big concrete support there and so forth. UNLV Nevada Test Site Oral History Project 13 So they built those sections, surveying them per section, as if the Earth were flat, and then when they all got connected over the seven thousand feet, you were off. Yes. Yes. And that was discovered by literally physically seeing that you weren’t getting a line- of- sight, is that right? Yes. Well, after it was done they checked the alignment with I believe it was a large gamma ray source with a film on the end and their aperture was only, I believe, half of what it should be or something like that. OK. Yes, OK. So that was corrected. Yes, as soon as people began to realize that, it was a straightforward thing to do. But an interesting thing is that it was discovered at the Mike shot— they had some line- of- sight pipes there, and it just strikes me now, why didn’t they learn that at Mike? But anyway, they had a pipe, or many pipes, at Mike that went from the source to a bunker. And maybe the distance wasn’t that long or the pipes were bigger diameter or whatever. Anyway, there are pictures. See, there are fireball pictures taken routinely of atmospheric shots. And there was a guy, Fran Porzell from Los Alamos, who was their fireball guy, and he was a very interesting guy, very sharp guy. He later left Los Alamos to go to the University of Illinois at Chicago. Anyway, I visited him once and he had so many stories to tell about the early days of the testing. It was just amazing. He said he went out to a shack and, if I may digress— Please do. At the Nevada Test Site in the early days— this is before Upshot- Knothole. [ 1953]. And in those days, you’d start the tests in February when it was very cold in Nevada, especially up on that mountain, on that mesa. And he said he went to the shack where there was a contractor. It was a UNLV Nevada Test Site Oral History Project 14 dark and stormy night [ laughter] and he was sitting in the shack and he had a pot- bellied stove in there, keeping warm. And he had lights and so forth, and he was doing some work there. And I remember Porzell stopped in, and he wanted to get warm, I guess, talk to the guy. And he was talking with him and the guy got up to put some fuel in the pot- bellied stove, and he asked him— it was just a chunk of— it wasn’t wood; it looked like just a piece of glass or plastic or something— and he said, What are you putting in there? And he said, I’m burning Comp- B. [ 00: 45: 00] That’s an explosive. So it turns out Comp- B has to be detonated, shocked, in order to explode, but if you just burn it, it just becomes a very benign heat source. But Fran, it took him back a little. He said he was sort of surprised. Anyway, that’s just an amusing story. Yes. Well, yes, I should say so. Let’s see, where were we? Oh, the fireball. OK, the fireball from Mike produced a jet that went down these pipes. So as you saw the pictures of the fireball, you’d see the fireball— we had a number of still shots of the fireball. Well actually, these were shots that were actually made to make measurements with. And there was a jet composed of, oh, hot luminous gases, very hot luminous gases, going down the pipeline. It hit the bunker and made another spherical ball of fire, and that spherical ball of fire was equal to some of the fireballs they saw in Nevada shots. It was really amazing. Well, what happened is— I don’t know as I understand this very well— but what happened is, as the initial fireball started growing out of Mike, it shined down on the pipeline and heated it up. And it so it traveled down there to the bunker. Well, of course everybody knew then that that was going to happen if you had the pipeline. So we knew that was going to happen to our pipelines. Well, nobody particularly was worried— well, I shouldn’t say that. People took that into account in the design of their experiment, and in the course of the building of the whole thing. And in addition to the jet that follows the pipeline on the exterior of UNLV Nevada Test Site Oral History Project 15 the pipeline, there’s also a jet that goes down the pipeline inside the pipe and would, of course, if it arrived to anywhere near our films they would be ruined. So we devised a plug that would move— there was another pipe— there was a plug that would be— spherical plug, a metal plug that would be moved by a very heavy duty spring that would slam this plug into the pipeline. And I guess it was— I forget the orientation. B