by Mike Bennett
Werner Heisenberg was a German theoretical physicist and one of the key figures in the development of quantum mechanics. He published his first major work in 1925 in a ground-breaking paper. Heisenberg was born in 1901, in Würzburg, Germany. He has been awarded both the Nobel Prize in Physics and the Max Planck Medal.
Heisenberg formulated the quantum theory of ferromagnetism, the neutron-proton model of the nucleus, the S-matrix theory in particle scattering, and various other significant breakthroughs in quantum field theory and high-energy particle physics. A prolific author, Heisenberg wrote more than 600 original research papers, philosophical essays and explanations for general audiences. His work is still available in the nine volumes of the Gesammelte Werke (Collected Works).
Heisenberg is synonymous with the so-called uncertainty, or indeterminacy, principle of 1927, and for one of the earliest breakthroughs in quantum mechanics in 1925. In recognition of his work on a unified field theory, the so-called “world formula”, he won the Nobel Prize for Physics in 1932 at the young age of thirty-one.
Heisenberg stayed firmly in Germany during the worst years of the Hitler regime, heading Germany’s research effort on the applications of nuclear fission during World War II. He also played a vital role in the reconstruction of West German science after the war. Heisenberg’s role was crucial in the success of West Germany’s nuclear and high-energy physics research programs.
No one better represents the plight and the conduct of German intellectuals under Hitler than Werner Heisenberg, whose task it was to build an atomic bomb for Nazi Germany. The controversy surrounding Heisenberg still rages, because of the nature of his work and the regime for which it was undertaken. Historians today are still investigating what precisely Heisenberg knew about the physics of the atomic bomb. They also ask how deep was his loyalty to the German government during the Third Reich, and assuming that he had been able to build a bomb, would he have been willing to do so?
Digging deep into the archival records among formerly secret technical reports, we have established that Heisenberg had to face the moral problem of whether he should design a bomb for the Nazi regime.
Only when he and his colleagues were interned in England and heard about Hiroshima did Heisenberg realise the full terror of this new weapon. He began at once to construct an image of himself as a “pure” scientist who could have built a bomb but chose to work on reactor design instead. Was this fiction? Many people think not. In reality, Heisenberg blindly supported and justified the cause of German victory. This is one of the 20th century’s great enigmas.
Heisenberg had been captured and arrested by US Colonel Pash at Heisenberg’s retreat in Urfeld, on 3rd May 1945, in what was a true alpine-type operation in territory still under the control of German forces. He was taken to Heidelberg, where, on 5th May, he met his old friend Samuel Abraham Goudsmit for the first time since the Ann Arbor visit in 1939. Germany surrendered just two days later. Heisenberg did not see his family again for eight months. He was moved across France and Belgium and flown to England on 3rd July 1945.
He was among ten top German scientists who were held at Farm Hall in England. This facility had been a safe house of the British Foreign Intelligence Service, now known as MI6. During their detention, their conversations were recorded. Conversations thought to be of intelligence value were transcribed and translated into English. The transcripts were not released until 1992.
The Americans soon realised the value of Heisenberg, and his knowledge was used during the Manhattan Project. Colonel Boris Pash reported directly to General Leslie Groves, commander of the Manhattan Engineering District, which was developing atomic weapons for the United States. The chief scientific advisor to Operation Alsos was the physicist Goudsmit. He was selected for this task because of his knowledge of physics, and because he spoke German and personally knew a number of the German scientists who worked on the Nazi nuclear energy project.
The objectives of Operation Alsos were originally to determine if the Germans had an atomic bomb program and to exploit German atomic-related facilities, intellectual materials, material resources and scientific personnel for the benefit of the US. Field personnel during the early stages of this operation generally swept into areas which had just come under the control of the Allied military forces, but sometimes they operated in areas still controlled by German forces.
Berlin had been the location of many German scientific research facilities. To limit casualties and loss of equipment, many of these facilities were dispersed to other locations in the latter years of the war. The Kaiser Wilhelm Institute for Physics had mostly been moved in 1943 and 1944 to Hechingen and its neighbouring town of Haigerloch, on the edge of the Black Forest, which eventually became the French occupation zone. This move and a little luck allowed the Americans to take into custody a large number of German scientists associated with nuclear research. The only section of the institute which remained in Berlin was the low-temperature physics section, headed by Ludwig Bewilogua, who was in charge of the exponential uranium pile.
Nine of the prominent German scientists who published reports in Kernphysikalische Forschungsberichte as members of the Uranverein were picked up by Operation Alsos and incarcerated in England. These scientists were Erich Bagge, Kurt Diebner, Walther Gerlach, Otto Hahn, Paul Harteck, Werner Heisenberg, Horst Korsching, Carl Friedrich von Weizsäcker and Karl Wirtz. Also incarcerated was Max von Laue, although he had nothing to do with the nuclear energy project. Goudsmit, the chief scientific advisor to Operation Alsos, thought von Laue might be beneficial to the post-war rebuilding of Germany and would benefit from the high-level contacts he would have in England.
CHAPTER 9
I believe the most significant technological development during the 1930s, which has had the most profound impact on the lives of everyone in the world, was when British scientists and engineers developed radar. By 1939, Britain had installed radar stations at many points along the coast. This gave the RAF vital warning of pending German attacks, as the aircraft could be detected while they were still assembling into formations over France.
Although the RAF was outnumbered four to one by the Luftwaffe in both warplanes and pilots in 1939, radar technology allowed the RAF to use their very limited resources to deny the Nazis air superiority over England. This subsequently resulted in Hitler having to cancel his planned invasion of Britain in 1940. This radar network was the world’s first true command and control system, and this model has been implemented by virtually every other nation since.
Subsequently, the same engineers improved this system by developing centimetric radar. Centimetric radar was first fitted to British convoy escorts in 1941, and was subsequently refined and miniaturised to allow it to be fitted to aircraft during 1942. This system was so effective that it could detect the surface reflection from the periscope of a submerged U-boat at a distance of up to 15km, depending on the sea state.
The development of centimetric radar again saved our skins, as without it, the U-boat fleet would have probably won the Battle of the Atlantic. This would have prevented the massive build-up of US and Canadian military personnel and equipment in southern England, and would therefore have prevented the D-Day invasion of Normandy which changed world history forever.
Following our discussion of radar, we will look at asdic, the ultrasonic system used to detect submerged U-boats, and the development of German U-boats and their countermeasures during World War II.
Considering the technical ingenuity and huge advances that the German scientists and engineers made during World War II, I have always been baffled by why they did not produce an effective weapon against convoy escorts. Most warships at that time had substantial deck and belt armour, in order to offer some protection against shells and torpedoes. The most vulnerable part of warships was the bottom of the hull, where the steel was fairly thin.
Confirmation of this weakness was demonstrated when the British X-Craft (midget submarines) were towed to the Nor
wegian fjord where the battleship Tirpitz was hiding. The Tirpitz was the sister ship of the Bismarck, and at the time they were the most powerful battleships in the world. However, a tiny X-Craft with a four-man crew managed to penetrate the torpedo nets surrounding the Tirpitz, and although they did not sink her, the charges they placed beneath the hull crippled this mighty ship for six months. After being repaired, Hitler had her moved to Northern Norway, well away from Britain. However, the RAF sent a squadron of Lancaster bombers to Northern Russia to refuel, and then sank her anyway.
Following World War II, when nations realised how vulnerable surface ships were to attacks from aircraft, no more battleships were built. Today, the capital ships in most navies are aircraft carriers.
I remember back in the early 1990s, I was in Perth working on a contract for Woodside Petroleum. While I was there, the USS Constellation carrier battle group paid a courtesy call to the port of Fremantle at the mouth of the Swan River. The USS Constellation has since been decommissioned, but she was a massive and impressive ship. I went on board her and spent the entire day on a guided tour of the ship, which was fascinating. I remember the captain telling us that when a US carrier battle group showed up on someone’s doorstep, only eight air forces in the world had more firepower than his single battle group.
That evening, most of the US Navy sailors were given shore leave. I remember that Fremantle and Perth looked like a new US Navy base. On the Constellation alone I believe there were 6,000 sailors, but there were plenty of US Marines in full dress uniform in order to make sure that the crew behaved themselves.
The attractive young Australian Kylie Minogue wannabes flocked to the fighter pilots like bees to a honeypot. The pilots looked like Tom Cruise in their starched white uniforms, with the F-14 tomcat buckles on their belts. It was surreal, almost like being on the film set when Hollywood was making the movie Top Gun.
Back to the North Atlantic now. I’m sure that many of the readers have seen Wolfgang Petersen’s superb film Das Boot, which shows both the bravery and despair of the Kriegsmarine U-boat arm in the early 1940s. The excellent film U-571 shows the same struggle from an American perspective. If you have not seen these films, I fully recommend them, as they give a fascinating insight into World War II submarine operations.
After the U-boat had launched its attack, it submerged and then remained largely defenceless against depth-charge attacks from the escort convoys.
The Germans could have designed and installed small, vertically firing torpedoes, which could have been kept in a pod behind the conning tower. They would only have needed to be able to travel a maximum of 300 metres, and could then detonate against the bottom of the hull of a convoy escort that was depth-charging the U-boat. As the escort convoys needed to steam directly over the position of the U-boat in order to launch a depth-charge attack, small vertical-firing torpedoes could well have saved a lot of German U-boat crews. History records that out of all of the military services involved in World War II, only the Japanese kamikazes (not surprisingly) suffered worse losses than the Kriegsmarine U-boat arm. During World War II, 40,000 Germans sailors served on U-boats. Thirty thousand never came home.
Chain Home was the title given to the radar defence established in Britain in the years that led to the Battle of Britain in 1940. Chain Home, along with Chain Home Low, provided Fighter Command with its early warning system so that fighter pilots could get airborne as early as was possible to combat incoming Luftwaffe aircraft.
The original chain of RDF stations (Radio Direction Finding – the term “radar” was not adopted until 1943) consisted of twenty-one stations. They were built from Southampton to the Tyne and the first was finished at Bawdsey in 1936, which also served as a radar training school. It was handed over to the RAF in May 1937. The radar station at Dover was handed over in July 1937. Both became operational in 1938. By the start of the war, RAF aircraft had been fitted with IFF (Identification Friend or Foe), which allowed each station to know whether what they were observing was friendly or not.
Chain Home radars had the ability to detect incoming aircraft at a variety of heights and distances. Targets that flew at 1,000 feet could be detected at a distance of 25 miles. Targets that flew at 2,000 feet could be detected at a distance of 35 miles. Targets that flew at 5,000 feet could be detected at a distance of 50 miles, and targets that flew at 13,000 feet could be detected at a distance of 83 miles.
Chain Home was helped by Chain Home Low. Thirty of these smaller stations were placed either on high ground, such as the North Downs, or on the coast. Those on the coast were very open to attack, and were frequently the victims of attacks by Stuka dive-bombers. Chain Home Low used a narrow searchlight beam that was useful against low-level flights but only over a shorter distance.
Chain Home and Chain Home Low were connected by telephone, and were able to exchange information and data, as well as pass it on the Filter Room at Fighter Command. By using information from Chain Home, Chain Home Low and the Observer Corps, Fighter Command had as much information as could have been acquired in such a situation using the technology that was available.
The information provided to Fighter Command was vital. Chain Home could detect Luftwaffe squadrons as they gathered over the coast of Northern France. Chain Home Low could detect aircraft flying low enough to avoid detection by Chain Home. With such information, Fighter Command usually had about twenty minutes to put fighter squadrons in the air. Timing was vital, as both Hurricane and Spitfire pilots preferred to attack from on high, as height gave them the advantage over the enemy. A Spitfire needed thirteen minutes to scramble and then get to its preferred flying height of 20,000 feet. A Hurricane needed slightly longer, about sixteen minutes. Therefore the twenty minutes given to them by Chain Home usually allowed Fighter Command to get into a more advantageous position.
The work of scanning a cathode ray tube within a Chain Home station was done by women in the Women’s Auxiliary Air Force. It was their expertise that made Chain Home a success, as the earlier they detected aircraft gathering over France, the earlier Fighter Command could assess and act on the situation. As the stations were inviting targets for Luftwaffe attacks, the work by its very nature was very dangerous.
The development of this radar system started in 1915, when Robert Watson-Watt joined the Meteorological Office, working in Aldershot in Hampshire. Over the next twenty years, he studied atmospheric phenomena and developed the use of radio signals generated by lightning strikes to map out the position of thunderstorms. The difficulty in pinpointing the direction of these fleeting signals using rotatable directional antennas led, in 1923, to the use of oscilloscopes in order to display the signals. The operation eventually moved to the outskirts of Slough in Berkshire, and in 1927 formed the Radio Research Station (RRS), Slough, an entity under the Department of Scientific and Industrial Research (DSIR). Watson-Watt was appointed the RRS Superintendent.
As war clouds gathered over Great Britain, the likelihood of air raids and the threat of invasion by air and sea drove a major effort in applying science and technology to defence. In November 1934, the Air Ministry established the Committee for Scientific Survey of Air Defence (CSSAD), with the official function of considering how far recent advances in scientific and technical knowledge could be used to strengthen the present methods of defence against hostile aircraft. Commonly called the Tizard Committee, after its Chairman, Sir Henry Tizard, this group had a profound influence on technical developments in Great Britain.
H. E. Wimperis, Director of Scientific Research at the Air Ministry and a member of the Tizard Committee, had read about a German newspaper article claiming that the Germans had built a death ray using radio signals, accompanied by an image of a very large radio antenna. Both concerned and potentially excited by this possibility, but highly sceptical at the same time, Wimperis looked for an expert in the field of radio propagation who might be able to pass judgement on the concept.
Watt, Superintendent of the RRS, was
now well established as an authority in the field of radio, and in January 1935, Wimperis contacted him asking if radio might be used for such a device. After discussing this with his scientific assistant, Arnold Wilkins, Wilkins quickly produced a back-of-the-envelope calculation that showed that the energy required would be enormous. Watt wrote back that this was unlikely, but added the following comment. “My attention is being turned to the difficult problem of radio detection, and numerical considerations on the method of detection by reflected radio waves will be submitted when required”.
Over the following several weeks, Wilkins considered the radio detection problem. He outlined an approach and backed it with detailed calculations of necessary transmitter power, reflection characteristics of an aircraft and needed receiver sensitivity. He proposed using a directional receiver based on Watt’s lightning detection concept, listening for powerful signals from a separate transmitter. Timing, and thus distance measurements, would be accomplished by triggering the oscilloscope’s trace with a muted signal from the transmitter, and then simply measuring the returns against a scale. Watson Watt sent this information to the Air Ministry on 12th February 1935, in a secret report titled The Detection of Aircraft by Radio Methods.
Reflection of radio signals was critical to the proposed technique, and the Air Ministry asked if this could be proven. To test this, Wilkins set up receiving equipment in a field near Upper Stowe, Northamptonshire.
On 26th February 1935, a Handley Page Heyford bomber flew along a path between the receiving station and the transmitting towers of a BBC shortwave station in nearby Daventry. The aircraft reflected the 6 MHz (49-metre) BBC signal, and this was readily detected by Doppler-beat interference at ranges up to 8 miles (13km). This convincing test, known as the Daventry Experiment, was witnessed by a representative from the Air Ministry, and led to the immediate authorisation to build a full demonstration system.