SR 52(8) 44-47.Pdf

PARESH R. VAIDYA August 2015 marks the 70th anniversary of the RTICLE

A atomic bombings. Here’s an attempt to unravel whether the Germans were

EATURE anywhere close to

F an atomic bomb.

While some wanted to exploit control of the US army. Apart from uranium fi ssion and the possibility intelligence experts from the military, of chain reaction for building a Super six scientists also were attached to Alsos. Bomb, others like Frederic Joliot Curie The scientifi c component of the mission OMETHING unusual happened in and his team thought of peaceful use was overseen by Samuel Goudsmit, the S1945, when the Nobel Prizes were like a controlled chain reaction in a Dutch physicist who discovered electron announced that winter. No one seemed nuclear reactor. If Britain, France and spin, and had since migrated to America. to know the whereabouts of the physics America could think of an explosive, so The headquarter of the mission was in prize winner, the German radiochemist could German scientists under Hitler’s England Otto Hahn. He was to be given the prize rule. With this assumption, labs in the Alsos had three target areas – Italy, for 1944 because the ceremony could not Allied countries put a moratorium on France and Germany. Italy was cleared be held that year due to the World War. the publication of scientifi c results on at the early stage itself of any suspicion. He was not found in Kaiser Wilhelm uranium and fi ssion. France was on the list in spite of being an Institute (KWI) in Berlin Dahlem, where But the censorship was causing Allied country because it was occupied he worked last. In fact, the Institute more worry. The results from the Italian by Germany early in the war and its labs itself was in a shambles, structurally and and German labs were also not coming were populated by German scientists, administratively, due to the War. out. The free world countries, who were may be by force. As the German labs were The 65-year-old scientist was under surely working on development of the damaged by the allied bombing, they had house arrest somewhere in England. nuclear weapon were under constant found France a safe place to work. He had for company two more Nobel pressure; their obvious fear was, In November 1944 Alsos could enter laureates from his country, the famous whether Germany was ahead of them France when the advancing allied army crystallographer Max von Laue and in pursuit of the nuclear weapon? After forced the Germans to retreat. They quantum physicist Werner Heisenberg. all, fi ssion was discovered in Germany, interviewed Frederic Joliot, son-in law of Seven more scientists who were associa- the only uranium mines in Europe, Marie Curie, who was the head at College ted with the German nuclear programme in Czechoslovakia, were captured by de France in Paris. He admitted that were also there. Hitler in 1939 and the only source of some German scientists indeed visited heavy water, Norsk Hydro, was also or worked in his laboratory. Two of his The War Scenario with him since Norway was taken visiting Germans, Diebner and Bagge During the 1930s, events on the political over. And of course, he had bright were later arrested when Alsos could front and in nuclear science were playing scientists. enter Germany. Incidentally, these two out parallely. Neutron was discovered in were also the members of the National Britain in 1932 and Hitler rose to power in Mission Alsos Socialist (Nazi) party. Prof. Friedrich von Germany in 1933. In January 1939 nuclear Out of this fear psychosis was born a Weizsacker, a disciple of Heisenberg, fi ssion was established in Germany and systematic reconnaissance programme was also in France during the occupation by September the war broke out in the in 1943, titled ‘Mission Alsos’. This was a years. Alsos men found his technical European part of the world. Like the two natural outcome for a project controlled papers sealed in a metal drum and camps in the battle fi eld, science also got by an army; the ‘Manhattan project’ dumped in a cesspool behind his house in divided into two. to build a super bomb was under the Germany.

SCIENCE REPORTER, AUGUST 2015 44 FEATURE ARTICLE

Above: Farm Hall ascertain the status of their knowledge where the German and if Germany indeed had plans to make scientists were kept in a bomb. detention A doubt has been expressed whether the scientists were aware of the recording The Hiroshima and so talked only in a sanitized manner. bomb was made However, this appeared unlikely from the of enriched nature of their discussions. It is not likely that ten persons could fake emotions 24x uranium. They 7 for six months. Consider this dialogue also knew the that happened: general principles Diebner: “I wonder whether there are of such a weapon. microphones installed here?” Heisenberg: “Microphones installed? Between 24th April to 3rd May 1945, were fi tted with hidden microphones. (Laughter) Oh, no, they’re not as cute Alsos located ten scientists one by one This part of the mission to record and as all that. I don’t think they know the from different places in Germany. The transcribe what they talked and then real Gestapo methods; they’re a bit old- last to be had was Heisenberg from his put the threads together was nicknamed fashioned in that respect.” home in Urfeld. He had reached there ‘Operation Epsilon’. It would also record That they were not pretending only two days back from Haigerloch, the the status of knowledge in nuclear fi eld in innocence came out clearly when the new location of his Institute, the KWI. His Germany. news of the Hiroshima bomb reached wife Elisabeth recounts in her book (Inner One may wonder, what was the use them on the 6th of August 1945. Like Exile,1980) that she was frightened seeing of fl ogging a dead horse? Germany was many people in the world outside, they fi ve soldiers, thinking they were Hitler’s nearly defeated when these scientists too did not believe it at fi rst. However, army men, but was relieved to know that were quarantined. The real reason was the disbelief was slowly worn out in two they were Americans! To get Heisenberg alarming. America did not want these days, when another atom bomb exploded (and also Hahn), the Chief of Alsos, scientists to land in the hands of Russian over Nagasaki. Colonel Pash and Goudsmit themselves troops, when Germany fell. Even before The most affected by the news was had gone to their residences. Heisenberg the war was over, or the nuclear weapon Otto Hahn, who blamed himself for this told them, “I have been waiting for you”. was proved to exist, USA was thinking devastating loss of innocent lives because He should have been, because three days of competition the USSR could provide he had discovered nuclear fi ssion. He was back, on 30th April, Hitler had killed them in the nuclear fi eld! This was the so delirious that he needed a constant himself and the great Third Reich was on seed for the cold war. companion to watch over him, lest he way to surrender soon. harm himself. Walther Gerlach, the The convoy of scientists was taken Transcripts administrative head at the Reich Research fi rst to Versaeilles, Le Vesinet (both in The Farm Hall where they were kept Council, overseeing the war work in France) and Huy in Belgium. The fi nal in house arrest had two army offi cers Germany, was also heard sobbing in his destination was Godmanchester near (Captain Brodie and Major Rittner) to room. His grief was about his failure as Cambridge in UK. The two storied villa look after their needs, both very polite. As a General. It was Hahn’s turn to console was called the Farm Hall. While they were they all spoke German, the tape recording him. He said, “Are you upset that we in custody of the British army, the aim was transcribed in German language did not make the uranium bomb? I thank was to fi nd out what they did in the past and then translated into English for the God on my bended knees that we did not two years in their laboratories. Was there seniors to review. These transcripts can be make it. Or are you upset that Americans still a danger from Germany? Their rooms considered reasonably reliable material to could do it better than we could?” 45 SCIENCE REPORTER, AUGUST 2015 FEATURE ARTICLE Left: The atomic bomb, nicknamed Little Boy, Heisenberg, how does a bomb explode. that was dropped on Hiroshima This series of discussions demonstrates the strong infl uence of isolation from the also made, but it is not clear if they used outside world! it. They had a good base in Heavy water The fact that Pu bomb uses implosion technology. They were attempting to get technique and the material is compressed criticality in a pile but had not operated a to a great degree and the assembly goes to self-sustaining chain reaction till then, at super critical mode, makes the discussion least as on record. on critical mass relatively less important. It appears surprising that there Although they had experts on explosives, With the help of newspapers they was no discussion or mention of the a couple of them were interned here in knew that the Hiroshima bomb was made letter Paul Harteck wrote to the German Farm Hall, it is clear that they were not of enriched uranium. They also knew War Ministry, indicating a possibility working on the implosion route. the general principles of such a weapon. of a nuclear explosive ‘many orders of While they were in the Farm Hall, However the issue to be debated was, magnitude more than the present one’. the British physicist PMS Blackett paid how much of uranium can make a bomb? Harteck was in-charge of the centrifuge them a visit. He and Heisenberg knew What is the critical mass of enriched work and his letter should have been as each other well. They discussed about the uranium? Critical mass is that mass in important as that of Einstein to President direction science would take in Germany which self-sustaining chain reaction can Roosevelt, both written around the same after the war. be established. It is different for the bare time, in 1939. Perhaps the army personnel The scientists were fi nally released fi ssile core and when it is shrouded in a monitoring the conversation did not on 3rd January 1946. shield or a refl ector. Then lesser material know of Einstein’s letter back then and will do the same job. lost this important reference in editing. Arguments and Counter During casual talk, without the aid Arguments of any papers and books, their estimate Unknown Plutonium Some utterances of Heisenberg in varied from 35 kg to about a ton! In Higher confusion prevailed about the the Farm Hall indicated that they addition, they never thought that the Nagasaki bomb which was made of intentionally went slow so that the Nazis enrichment levels could be taken to levels plutonium. Firstly the naming of the did not get the bomb to play havoc. This as high as 90% and beyond. This defrayed element number 94 was not known to is plausible because many scientists the level of work done in Germany. them yet. Hence the newspapers’ garbled like him and Hahn were known to be Some people consider that the higher report mentioning the word ‘Pluto’ indifferent to the National Socialists to estimate by Heisenberg for the required confused them. They were not aware of the extent that they disliked them. For quantity of enriched uranium dissuaded the scale at which America had worked, being an admirer of Einstein, Nazis called him from going forward on the bomb thus could not imagine that the element Heisenberg a ‘white Jew’. idea. He thought that this quantity could 94 could be a workshop reality. Hahn had resigned from the not be had before the war was over. It is interesting to read in the lecturer’s post of the Berlin University Their discussion gives a clear transcripts about scientifi c brainstorming in 1933 only to avoid attending the party picture about a couple of facts: They in which wild suggestions are thrown, meetings. However, leader of the Alsos were working on three routes of uranium like freezing the Neptunium to stop Mission, Samuel Goudsmit was not enrichment viz. gaseous diffusion, beta activity or using Proto-actinium to amused by this moral high ground taken centrifuge and mass spectrometer based; get a chain reaction. You come across a by Heisenberg. He wrote his own book a mention of photo-chemical method is sincere student in Hahn who learns from about Alsos Mission after the war and SERBER’S GUN BARREL An explosion occurs when a copious energy is released in short Ɵ me and in contained space. It is as true for a Diwali cracker as for an atom bomb. Just as the Farm Hall transcripts were declassifi ed in 1993 some lecture material was declassifi ed a year earlier. It came as a book Ɵ tled Los Alamos Primer and was based on the lectures given by Robert Serber to the scienƟ sts working for the ManhaƩ an Project, about the physics and techniques of making a nuclear weapon. He described two types of atom bombs – one called the Gun Barrel design and the other Serber’s diagram for Gun an ‘implosion device’. Barrel assembly (above) In the gun barrel type of bomb two lumps of slightly lesser than criƟ cal mass are kept separately and brought together at high speed. This results in formaƟ on of a supercriƟ cal assembly and it explodes because of sudden release of enormous energy. In the fi gure here drawn by Serber himself, a popular design of gun barrel assembly is given. A uranium sphere with a cylindrical cavity is the target and the cylindrical piece of uranium is called the bullet. The white porƟ on is the refl ector over the sphere. The bullet is rapidly shot into the cylinder to trigger the explosion. The discussion at the Farm Hall was about how big this sphere needs to be? In the implosion method a sub-criƟ cal mass is compressed isostaƟ cally to enhance its density, thus Schematic of the making it supercriƟ cal. It is a suitable method for plutonium. implosion method SCIENCE REPORTER, AUGUST 2015 46 FEATURE ARTICLE Scientists Detained at the Farm Hall Name Age then Area of Work Max Theodore Felix Laue 65 Crystallographer; no connection with bomb Otto Hahn 66 Discovery of Fission; Director, KWI of chem W. Gerlach 55 Head of German Research Centre W. Heisenberg 44 Head KWI of physics, Fission expert P. Harteck 42 Heavy Water production K. Diebner 40 Uranium and Explosive research Three of the Farm Hall heavies: Werner Heisenberg, K. Wirtz 35 Heavy Water, Isotope separation Otto Hahn, and Kurt Diebner The most affected by the news of bombing E. Bagge 32 Isotope separation Hiroshima was Otto Hahn, who blamed himself Carl F. von Weizsacker 32 Theoretical physics for this devastating loss of innocent lives H. Korsching 32 Isotope separation attempted to make a case that “Germans for some more time. Robert Jungk wrote Powers, again giving Heisenberg’s side of could not make the bomb due to the failure a book, Brighter than Thousand Suns the story. of the German scientifi c organization and (1956) to narrate the German side of the All these view points and certain stupidities on the part of German bomb story as if to counter Goudsmit’s interpretations do not change one ground Scientists” (Alsos, 1947, page 232). allegations. The sub-title of his book was truth that there was no bomb on German Goudsmit was not at all charitable to ‘the moral and political history of the soil till they surrendered. But the debate Germans because his father and mother atomic scientists’. However, in the second will never cease. It is because the science were taken to a concentration camp at edition (1970) it was changed to ‘the historians are dealing with abstract things Auschwitz in Poland and killed. But his personal history of the atomic scientists’. like ‘intentions’ and ‘capabilities’ and not criticism irritated the German scientists He described trials and tribulations of the physical evidence. who were already stressed being viewed scientists under Nazi rule; he even uses As recent as in 2011 a large quantity under the magnifying lens. Max von Laue the Gandhian phrase ‘passive resistance’ (more than 1 lakh drums!) of nuclear said that Goudsmit could not be impartial to describe their attitude. waste was found in a rock salt mine because he had suffered at the hands of There are numerous other accounts near Hanover in Germany. The debate the Nazis and argued that the service to of their struggle with conscience. Even has been resurrected but there is no Nazism was different from service to the inside Farm Hall prison, three scientists use of conjecture in the absence of any German people. Philips Morrison, while who were members of Nazi party were knowledge about the radioactivity level reviewing the book Alsos writes that the at pains to explain their stand to the and the dominant nuclei in the waste. It argument like Laue’s, is given now in other upright scientists. Diebner says could be a mining waste, laboratory waste retrospect, after Germany was defeated. that he joined the SS, thinking that after or a later vintage waste from an unlikely The facts that came out after the war the war positions would be given only to accident in a silo of the theatre force. The made it clear that the Army Weapons members of the Party! details are not made public. Bureau, which was controlling the Kaiser Meanwhile Heisenberg and Let us go back to Hahn’s Nobel Prize. Wilhelm Institute of Physics, gave up the Goudsmit kept writing to each other till The Allied military fi rst procrastinated chase of the Super Bomb as early as 1942. 1967, when they called truce. Goudsmit on the delivery of the letter of offi cial This may be because they were convinced emphasized one point which is valid any announcement from the Nobel committee that the so called ‘new weapon’ would time: science cannot grow under a Fascist of Hahn receiving the Prize. And when the not be ready before the war and hence environment; liberal values only can time came for attending the prestigious would not infl uence the outcome. This foster its growth. ceremony, the permission to travel to logic could have been articulated and The transcripts of Farm Hall Sweden was refused. They wanted Hahn conveyed by the veteran scientists who dialogues were de-classifi ed only in 1993. to send a regret citing ‘personal reason’. did not wish to augment the destructive Two books giving the transcripts were When Hahn resisted and wanted to power of the Nazis. published along with the comments of mention the detention, he was told the Heisenberg while in Farm Hall said, the compilers. They are Operation Epsilon: letter would not be dispatched. “The whole structure of the relationship The Farm Hall Transcripts introduced by For a scientist there is no greater between the scientist and the State in Sir Charles Frank (Institute of Physics honour and pleasure than receiving Germany was such that although we publishing, 1993) and Hitler’s Uranium the Nobel Prize. Hahn was greatly were not 100% anxious to do it, on the Club: The secret recordings at Farm Hall disappointed. But this is how military other hand we were so little trusted by by Jeremy Bernstein (Aspon Colorado minds work – everywhere, at all times. the state that even if we had wanted to publishing, 1996). As the transcripts do do it, it would not have been easy to get not give out a great picture of German Dr. Paresh R. Vaidya retired from the Bhabha it through.” Anyway, there was no case readiness, one more spell of books and Atomic Research Centre, Mumbai as Scientifi c to de-rate the capability of the German articles came out during 1990s, fi fty years Offi cer (H) and Head, Quality Control Section, scientists. after the bomb. The most important of QAD. Address: Flat 3, Nishant Surabhi, Plot 110, However, the bitterness and the mind them was the fat biography of Heisenberg Sector 28, Vashi (Navi Mumbai)-400703; Email: games about the German bomb continued titled Heisenberg’s War by Thomas [email protected] 47 SCIENCE REPORTER, AUGUST 2015