Samuel Cohen's Neutron Bomb: Debunking Communist Cold War Propaganda

Seen in 1999, Sam Cohen holds up a peace medal given to him by Pope John Paul I. He designed the neutron bomb with just pencil, paper and a slide rule. (San Jose Mercury News)


Above: the target for Sam Cohen's neutron bomb was these T-54/55 Russian main battle tanks, which had the highest production run of any tank ever made (over 86,000 were manufactured). They were manufactured chiefly for the invasion of Western Europe, once tactical nuclear weapons had been removed by political lobbying of Western disarmament activists via the Kremlin-controlled World Peace Council based in Moscow.

“The first objection to battlefield ER weapons is that they potentially lower the nuclear threshold because of their tactical utility. In the kind of potential strategic use suggested where these warheads would be held back as an ultimate countervalue weapon only to be employed when exchange had degenerated to the general level, this argument loses its force: the threshold would long since have been crossed before use of ER weapons is even contemplated. In the strategic context, it is rather possible to argue that such weapons raise the threshold by reinforcing the awful human consequences of nuclear exchange: the hostages recognize they are still (or once again) prisoners and, thus, certain victims.”

- Dr Donald M. Snow (Associate Professor of Political Science and Director of International Studies, University of Alabama), “Strategic Implications of Enhanced Radiation Weapons”, Air University Review, July-August 1979 issue (online version linked here).

'The neutron bomb, so-called because of the deliberate effort to maximize the effectiveness of the neutrons, would necessarily be limited to rather small yields - yields at which the neutron absorption in air does not reduce the doses to a point at which blast and thermal effects are dominant. The use of small yields against large-area targets again runs into the delivery problems faced by chemical agents and explosives, and larger yields in fewer packages pose a less stringent problem for delivery systems in most applications. In the unlikely event that an enemy desired to minimize blast and thermal damage and to create little fallout but still kill the populace, it would be necessary to use large numbers of carefully placed neutron-producing weapons burst high enough to avoid blast damage on the ground [500 metres altitude for a neutron bomb of 1 kt total yield], but low enough to get the neutrons down. In this case, however, adequate radiation shielding for the people would leave the city unscathed and demonstrate the attack to be futile.'

- Dr Harold L. Brode, RAND Corporation, Blast and Other Threats, pp. 5-6 in Proceedings of the Symposium on Protective Structures for Civilian Populations, U.S. National Academy of Sciences, National Research Council, Symposium held at Washington, D.C., April 19-23, 1965.

“You published an article ‘Armour defuses the neutron bomb’ by John Harris and Andre Gsponer (13 March, p 44). To support their contention that the neutron bomb is of no military value against tanks, the authors make a number of statements about the effects of nuclear weapons. Most of these statements are false ... Do the authors not realise that at 280 metres the thermal fluence is about 20 calories per square centimetre – a level which would leave a good proportion of infantrymen, dressed for NBC conditions, fit to fight on? ... Perhaps they are unaware of the fact that a tank exposed to a nuclear burst with 30 times the blast output of their weapon, and at a range about 30 per cent greater than their 280 metres, was only moderately damaged, and was usable straight afterwards. ... we find that Harris and Gsponer’s conclusion that the ‘special effectiveness of the neutron bomb against tanks is illusory’ does not even stand up to this rather cursory scrutiny. They appear to be ignorant of the nature and effects of the blast and heat outputs of nuclear weapons, and unaware of the constraints under which the tank designer must operate.”

- C. S. Grace, Royal Military College of Science, Shrivenham, Wiltshire, New Scientist, 12 June 1986, p. 62.


Above: Lying CND propaganda postcard on the neutron bomb issued by Yorkshire Region CND (campaign for nuclear disarmament). The back of the postcard falsely claims: 'Civilians, rather than easily protected tanks, will be the main targets.' You can't easily protect a tank from hundreds of thousands of rads of extremely high energy (14.1 MeV) fusion neutrons, which is the whole point of the neutron bomb. The well-known good absorbers for low energy neutrons in a nuclear reactor (cadmium and boron) are relatively ineffective at capturing such high energy neutrons, and if you use heavy metals to scatter and slow down the high energy neutrons, like steel or depleted uranium, you get gamma rays given off when the neutrons deposit energy in the nuclei they strike. So then you have a secondary radiation hazard, not to mention the immense weight increase to the tank which would have major implications (tanks are normally extremely heavy and a massive increase in armour would have severely detrimental effects, such as bogging them down more easily, increasing fuel consumption and decreasing speed). If civilians (not in tanks) were the targets, you wouldn't need to use short-range radiation effects because you could just use blast and fallout against them, but they weren't the targets. As the lying CND propagandarists knew, the deterrent targets were the Warsaw Pact communist tanks which outnumbered those on the West by three-to-one:

Joseph C. Harsch, 'Neutron Bomb: Why It Worries The Russians', Christian Science Monitor, August 14, 1981, p. 1: "[there] are 19,500 tanks in the Soviet-controlled forces of the Warsaw Pact aimed at Western Europe. Of these, 12,500 are Soviet tanks in Soviet units. NATO has 7,000 tanks on its side facing the 19,500."


Above: Samuel Cohen's calculation of the gamma dose rate from deposited fallout formed Appendix D of Glasstone's 1950 Effects of Atomic Weapons. Cohen also contributed the analysis of dose rates to aircraft flying inside the mushroom cloud at various times after detonation. In his fallout calculations (Appendix D), Cohen ignored air scattered gamma ray contributions and just summed the direct gamma ray contributions from a smooth plane. It turned out that this approximation gave results which are accurate for typical rough ground if scattered gamma rays are included. For a smooth, infinite, uniformly contaminated surface including the contribution from air scattered gamma rays, 50% of the dose rate at 1 metre height comes from fallout within a 15 metres radius; for Cohen's approximation (ignoring air scatter) this radius is only 8 metres which is about the same as for rough terrain (where the terrain absorbs some of the radiation, particularly from great distances) where air scatter is included.

While he did not discuss Dr Samuel T. Cohen’s neutron bomb in The Effects of Nuclear Weapons, Glasstone in an article called 'Nuclear Weapons' for Microsoft's Encarta 97 critically argued that 95 % clean neutron bombs are the way forward, to totally avoid collateral damage in nuclear war (published by Microsoft Corporation in the Microsoft Encarta 97 Encyclopaedia CD-ROM, 1997):

‘If an H-bomb were made with no uranium jacket but with a fission trigger ... as little as 5 percent of the total explosive force might result from fission; the weapon would thus be 95 percent clean. The enhanced radiation fusion bomb, also called the neutron bomb, which has been tested by the United States and other nuclear powers ... is considered a tactical weapon because it can do serious damage on the battlefield [assuming a 1-kt air burst at 500 m altitude], penetrating tanks and other armoured vehicles and causing death or serious injury to exposed individuals, without producing the radioactive fallout that endangers people or structures miles away.’

Samuel Glasstone was well aware of the facts on the neutron bomb, for he had taught classified nuclear weapons design at Los Alamos until he retired and moved to Oak Ridge (Glasstone was co-author with Leslie M. Redman of the originally Secret - Restricted Data June 1972 report WASH-1038, An Introduction to Nuclear Weapons):

'When I arrived at the [Los Alamos] Lab 36+ years ago ... though I was a lowly postdoc, we took a course on nuclear physics (as did every new employee) and then a class on elements of bomb design both taught by Samuel Glasstone. This was required training. ... After that approximately 3 weeks of training, I understand what the Lab was about and why it was important to the nation. I'm certain it contributed to my wanting to stay on after my postdoc and has helped me in my work over the years. This was part of the "openness" despite the secrecy associated with the Lab. I believe we have lost this over the years ...' - Dr David Forslund

'During the Manhattan Project, classification was easy: everything in the project was classified. Then and later, information on nuclear weapons was "born classified" in the Restricted Data category. During the [Los Alamos National] Lab's orientation for new hires in the mid-1960s, Sam Glasstone, who had been a chemist in the Manhattan Project, drew one circle on the blackboard and another inside it. "Drawing concentric circles used to be classified," he joked. Fission bombs are designed in concentric circles.' - Dr Cheryl Rofer, Los Alamos National Laboratory, Part I - Historical Perspectives ['Cheryl Rofer is a chemist who worked for the Los Alamos National Laboratory for 35 years. ...'], Word Worth, September 2004, volume IV, No. 9.

Above (click on images to enlarge): the neutron bomb is included under the title 'enhanced neutron weapon' in Philip J. Dolan's originally secret manual Capabilities of Nuclear Weapons, DNA-EM-1, U.S. Department of Defense, Chapter 5, Nuclear Radiation Phenomena, August 1981 revision. According to the Medical NBC Battlebook, USACHPPM Tech Guide 244, May 2000, page 2-18, a 3 kt enhanced neutron weapon with a fission yield of 50% (i.e. 5% of yield as residual radiation, which is a trivial effect for the burst height of the neutron bomb) will release 30% of its energy as blast (trivial for the 720 metres height of burst for tactical use of a 3 kt neutron bomb), 20% as thermal radiation (again, relatively trivial even near ground zero, due to yield and burst altitude), and 45% as inital nuclear radiation. These ratios will be altered for other fission yields. At very low yields, there is a problem with using a small fission primary to ignite the fusion stage in a Teller-Ulam device because the fraction of yield released as X-rays by a very low yield fission device is small (it depends strongly on the yield to mass ratio of the primary stage), thus the fusion stage ignition-efficiency due to X-ray ablation induced recoil falls. Most of the energy from a low yield primary stage is in a relatively slow moving (compared to light-velocity X-rays) debris hydrodynamic shock wave, that delivers energy to the fusion stage slowly and without efficient focussing. Fortunately, the neutron bomb is not concerned with maximising Teller-Ulam efficiency, but with producing a small yield with a maximised neutron output!

The basic mechanism of the neutron bomb was discovered by Samuel Cohen of RAND Corporation in 1958 when studying the neutron outputs from two Lawrence Livermore National Laboratory clean (low fission) bomb designs (Dove and Starling) of low yield devices for peaceful explosive uses like excavating harbours, canals, and mountain passes, and is simply that the case thickness needed by a Teller-Ulam device to channel X-rays from primary to secondary scaled as the cube root of the total yield. Hence the casing required is 10 times thicker for 1 Mt than for 1 kt, so in a 1 kt Teller-Ulam device, most of the neutrons can escape from the thin casing, while in a 1 Mt Teller-Ulam device the neutrons are mostly absorbed because of the much thicker casing required. Thus neutron bombs have a yield range of 1-10 kilotons, with fission yield varying from 50% at 1-kiloton to 25% at 10-kilotons (all of which comes from the primary stage). The neutron output per kiloton is 10-15 times greater than for a pure fission implosion weapon.Above: neutron attenuation in air according to energy, in Philip J. Dolan's originally secret manual Capabilities of Nuclear Weapons, DNA-EM-1, U.S. Department of Defense, Chapter 5, Nuclear Radiation Phenomena, August 1981 revision (the simple geometric inverse square law of divergence of neutrons from a point source isn't included in the shielding curves above). Notice that over small distances in the air, the neutron fluence is higher than in a vacuum, because there is little attenuation by air over a short distance, but you get an additional large neutron dose from neutrons being scattered back at you which have gone past (and also through) you, and have then been scattered back at you, by large number of nuclei which are obviously located at greater distances (beyond your distance from the detonation!). This is also why tanks can't be protected with a relatively light weight shield on top of the crew compartment, as we shall see later on: it is not possible to protect tanks existing against neutron radiation without adding so much mass the turret would be retarded and the performance of the tank would be crippled. A tank designed to properly protect its crew against 14.1 MeV neutron bomb neutrons and with a big enough engine to perform reasonably well, would be so heavy it would be swallowed up by the earth and simply disappear into soft ground, being rendered useless (the shielding of 14.1 MeV neutrons has nothing to do - either in mechanism or in amount of shielding - with the easy-to-shield thermalized 0.025 eV neutrons by cadmium control rods in a nuclear reactor).
Above: neutron bomb doses compared to other weapons, in Philip J. Dolan's originally secret manual Capabilities of Nuclear Weapons, DNA-EM-1, U.S. Department of Defense, Chapter 5, Nuclear Radiation Phenomena, August 1981 revision.

The enhanced neutron weapon or ‘neutron bomb’ is just a relatively clean very low yield two stage Teller-Ulam device; the low total yield means that only a very thin steel casing is required to reflect X-rays from the fission primary on to the fusion secondary stage. The thin casing of such a weapon ensures that most of the 17.6 MeV fusion energy from deuterium and tritium fusion into helium-4 escapes as neutrons: 80% of the energy is carried by neutrons, and 20% is carried by the helium-4 nucleus or alpha particle. This suppresses the amount of energy available for producing the blast and thermal radiation effects.

The primary strategic uses of clean, low fission yield enhanced neutron warheads are:

(1) to avert EMP collateral damage (due to low fission yield and low total yield) for ABM missiles by using the neutron output to melt and destroy plutonium cores in incoming ICBMs (neutrons have a long range in space);

(2) to deter massed tank attacks in cities or close to friendly forces. The deterrent here is the fact that neutron irradiated tank crews would be disabled within minutes and dead within hours to days; and

(3) to deter warship assaults by the threat of putting them out of action without nearby collateral damage or fallout.

Steel armour is resistant to blast and heat, but provides little shielding against fast fusion neutrons. The well-known neutron absorbers used in nuclear reactor control rods are little use against neutron bomb radiation, because they are good absorbers of 0.025 eV ‘thermalized’ neutrons in a nuclear reactor with a moderator, but useless against the 14.1 MeV neutrons from neutron bomb fusion, which have 560 million times more energy than thermal neutrons. Heavier armor, like that of the M-1 tank, employs depleted uranium which (although it is not significantly fissioned by low-energy thermal neutrons) actually increases the effectiveness of neutron radiation because it undergoes fission when hit by the 14.1 MeV high energy neutrons from neutron bomb, generating additional neutrons and becoming radioactive.

Because the blast and heat are suppressed in the neutron bomb, they have a similar damaging range to the lethal neutron radiation, so there is no collateral damage outside the target area. In some cases, a few broken windows can occur at greater distances, but there is no risk of dangerous blast-wind accelerated glass fragments, because the blast winds are trivial outside the neutron irradiate area.

Provided that the weapon was not used in a thunderstorm, no fallout effects would occur from the use of a neutron bomb, as the combination of 500 m burst altitude and low yield prevents fallout in addition to significant thermal and blast effects. The reduction in damage outside the target area is a major advantage of such a weapon to deter massed tank invasions. An aggressor would thus be forced to disperse tanks, which would make them easier to destroy by simple hand-held anti-tank missile launchers.

In 1979, Samuel Cohen was in Paris helping the French build neutron bombs, when presidential candidate Ronald Reagan came through on a European tour. Cohen met with Reagan to brief him on the neutron bomb. Reagan grasped the idea of neutron weaponry immediately, and made a pledge to Cohen that he would reverse Carter administration policy by building and deploying neutron bombs.

Sam Cohen's book, The Truth About the Neutron Bomb: the Inventor of the Bomb Speaks Out, William Morrow and Co., New York, 1983, on page 48 states that he referred to the two 1958 Lawrence Livermore National Laboratory clean (low fission) enhanced neutron Plowshare (peaceful explosives) devices by their code names Dove and Starling:

'The first time I recall seeing the term "neutron bomb" was in U.S. News and World Report. This was in May 1959, when the magazine revealed that the U.S. was working on a "neutron 'death ray' bomb which would kill man with streams of poisonous radiation, while leaving machines and buildings undamaged.'

Cohen adds in a footnote on that page that the neutron bomb: 'never did catch on at RAND, which was far more of a campus department than an objective think tank. ... However, I did find out that a good-looking blonde down the hall had expressed interest in hearing my briefing. ... some months later I married her.' On page 61 he explains: 'From the very beginning of the neutron bomb saga there has been one thing that particularly impressed - better yet, depressed - me about renowned American scientists. This is their ability to be impeccably careful and responsible when working in their fields of specilization (if they're not, their colleagues will catch them and even punish them) but their sloppiness and irresponsibility when giving their scientific opinion on nuclear weapons when they have an ideological bias against them, because they know that their colleagues, who share their bias, don't give a damn when they do this.'


Above: Cohen's comparison of the destruction he saw first-hand in Korea from conventional war (1950-3), with the nuclear destruction in Hiroshima. The only difference is that Hiroshima had mainly wooden houses which were burned down, whereas Seoul had more brick and concrete buildings. The Hiroshima photo was taken on 12 October 1945 (U.S. Army Photo #SC 290666); the Seoul photo was taken on 1 November 1950 (U.S. Army Photo #SC 352260).

In 1961, Cohen briefed President Kennedy's national security advisor McGeorge Bundy on the neutron bomb (The Truth About the Neutron Bomb, 1983, pp. 72-3): 'His response was that if we had to use nuclear weapons to stop the Red Army from taking over Europe, he would favor hitting them with the biggest weapons we had. My riposte was: "On our allies' soil?" He didn't reply. ... He had gotten the point. That ended the meeting.' Consequently, President John F. Kennedy authorized the 1963 testing of the neutron bomb underground by Livermore scientists in the Nevada, which 'worked out extremely well' (page 83).

Soviet Premier Nikita Khrushchev fanatically denounced the discriminate neutron bomb in his speech to the Romanian Party Congress in Bucharest: 'More and more frequently now, we hear from statesmen and military leaders, particularly in the United States, that they are working toward the creation of a neutron bomb. ... They are acting on the principle of robbers wanting to kill a man in such a way that his suit will not be stained with blood, in order to appropriate the suit. ... the bestial ethics of the most aggressive representatives of imperialism. ... Man to them is nothing. For them the main thing is to plunder, a quest for profit which prods the imperialists to the most horrible crimes.'



Cohen prints a Dunagin's people satire from 1977, showing a politician ordering physicists to modify the neutron bomb to fit Khrushchev's alleged morality:

'There are strong moral objections to a bomb that kills but doesn't destroy buildings. Fix it so it destroys buildings, too.'

On pages 91-2, Cohen explains: 'A discriminate tactical nuclear weapon is one whose effects can be confined mainly to the military target, minimizing damage to non-combatants and their property. So neutron bombs, which are intended to kill enemy soldiers but spare civilians and their towns, are, by this definition, discriminate weapons. For example, had they been available in the Korean War [which Cohen saw first hand] for use against enemy soldiers fighting in the city of Seoul, their application would have represented a highly discriminate attack - far more so than was the attack that actually took place using conventional weapons, and which pretty well levelled the city.'

He was inspired to invent and promote the neutron bomb by the vast civilian casualties from collateral damage due to the conventional weapons he saw in Korea, and by the NATO 'Carte Blanche' exercise of 23-28 June 1955, which predicted that the 268 nuclear explosions over 3 days in Germany which would be needed to defend Western Europe from Warsaw Pact forces would kill 1,500,000 civilians, and injure a further 3,500,000. By using neutron bomb air bursts (500-1,000 m altitude for 1-10 kt yields), all of these civilian casualties could be avoided. There would be no significant fallout, and the small area of neutron induced activity at ground zero decays very rapidly, as in Hiroshima and Nagasaki. The uselessness of conventional defences to stop massed tank invasions was clearly demonstrated by the French anti-tank Maginot Line, which failed in World War II when Nazi tanks bypassed it and went through the Ardennes Forest to invade France.



On 12 July 1977, President Jimmy Carter publically announced the development of a neutron bomb to deter massed Soviet tank invasions of Western Europe because the Warsaw Pact had 25,000 tanks in Eastern Europe, ready for an invasion. Cohen on page 109 points out that President Reagan in 1981 stated that the Soviet Union responded by pumping over $100,000,000 into an anti-neutron bomb 'peace' propaganda campaign. Premier Leonid Brezhnev offered to refrain from building the neutron bomb if America agreed to do likewise! President Carter responded (Cohen, p. 111):

'The Soviets know and President Brezhnev knows that the neutron weapon is designed to be used against massive and perhaps overwhelming tank forces. ... The neutron weapons are designed to equalize that inequality. ... The Soviets have no use for a neutron weapon, so the offer by Brezhnev to refrain from building the neutron weapon has no significance in the European theatre and he knows this.'



But Carter chickened out when the Soviet anti-neutron bomb propaganda assault on the media commenced. Moscow radio was followed by 28 different European communist parties statements denouncing the neutron bomb as an immoral weapon, and the Soviet funded 'World Peace Council' (similar to Hitler's '25-year-peace plan' propaganda spin before World War II) called a week of international anti-neutron bomb action in August 1977, lying that the neutron bomb was designed to kill civilians and leave cities intact for American invasions and plunder. The pro-communist left-wing media of the West, plus the anti-nuclear biased groups, lapped it all up. Grigori Gokshin, Secretary of the 'Soviet Peace Committee' from 1973-91, conducted war on the neutron bomb through the media to protect the Soviet tank advantage in Europe!



The media pressure, including continuing bias from the BBC, which still falsely claims that horrific fallout and collateral damage was a good thing because it allegedly increased deterrence (in fact, collateral damage potential reduced deterrence by making the threat totally non-credible: as proved by the fact that the Soviets were so fearful of the neutron bomb but were undeterred by nuclear weapons which would produce collateral damage and amassed a tank superiority in the Warsaw Pact for a possible invasion of Western Europe precisely because they knew that indiscriminate American weapons could not be used without millions of casualties, so that such indiscriminate threats had zero, nil, nada, zip credibility as a deterrent to war or aggression), forced President Carter on 7 April 1978 to delay his decision to produce neutron warheads, and although he ordered the production of the fusion capsules for neutron bombs in October 1978, he continued to delay making a decision on the production of the rest of the bomb! (Cohen, page 115.) The next month, Premier Brezhnev responded to Carter's half-hearted decision by telling a group of U.S. senators visiting Moscow that 'many years ago, we tested but we never started production of that weapon'. They didn't want or need low yield anti-tank tactical weapons, because they were the ones with the 4-to-1 tank superiority in Europe! They didn't want or need low yield collateral-avoilding neutron bombs, because they didn't give a damn about civilian casualties and collateral damage. But Premier Brezhnev pretended that the reason they did not have neutron bombs was because they were morally superior!

Carter continued to postpone his decision on the neutron bomb. Undeterred, the Soviet Union in 1979 invaded Afghanistan with tanks in what many considered a forerunner to an invasion of Western Europe and the rest of the free world. President Ronald Reagan was elected, and he ordered the production of 700 neutron bombs (350 nuclear 20-cm diameter shells for howitzers, and 350 W70 warheads for tactical Lance missiles) on 8 August 1981 to help to deter an invasion from the 19,500 Warsaw Pact tanks. Responding on 8 March 1983 to the Soviet 'peace morality' propaganda, Reagan pleaded: 'I urge you to beware the temptation to label both sides "equally at fault", to ignore the facts of history and the aggressive impulses of an evil empire, to simply call the arms race a "giant misunderstanding", and thereby remove yourself from the struggle between right and wrong, and good and evil.'

The neutron bomb is efficient against massed tank invasions, thus an aggressor would be forced to disperse tanks; making them easy for troops to destroy or halt individually using simple hand-launched anti-tank rockets.

Dr Edward Teller and Dr Albert L. Latter were the first to suggest this solution on page 171 of their book Our Nuclear Future: Facts, Dangers and Opportunities, Criterion Books, New York, 1958:

'In a nuclear war it will not make sense to use massed manpower. Any such concentration will provide too good a target for atomic weapons. ...

'Any fighting unit in a nuclear war will have to be small, mobile, inconspicuous and capable of independent action. ...

'If an invader adopts extreme dispersion, it will become impossible to defeat him with atomic weapons. But a very highly dispersed army can be defeated by a determined local population [with hand-held anti-tank rockets, etc.]. Therefore the main role of nuclear weapons might well be to disperse any striking force so that the resistance of people defending their homes can become decisive. Nuclear weapons may well become the answer to massed armies and may put back the power into the hands where we believe it belongs: the hands of the people.'



On page 135 of The Truth About the Neutron Bomb, 1983, Cohen stated that the neutron bomb is inefficient against cities with civilians because: 'All they have to do is construct very simple radiation shelters and, as the eemy approaches, get into them. ... Because there is no blast to contend with ... all that is called for is piling several feet of earth over the shelter. And dirt is cheap.' Earth slows down neutrons efficiently (removing neutron energy) because it contains a lot of light elements, but the heavy iron nuclei in steel tanks don't absorb much energy when they scatter neutrons around, so tanks only have a protective factor of about 2 against neutron radiation (tanks have a protection factor of 10 against initial high energy gamma rays, which are better attenuated by scattering the many electrons in iron atoms).








This is simple physics, but chemist George Kistiakowsky falsely claimed in MIT's Technology Review that 'A 10-cm (about 4 inches) layer of a suitable hydrogenous material, say water in plastic bags over the crew compartment, followed by a thin sheet of cadmium metal, would reduce neutron radiation intensity by about a factor of 5.' A factor of 5 reduction only reduces the neutron range by 15-20% because the dose drops off sharply with distance. But the factor of 5 calculation is false anyway, as Cohen explains on page 142, because the majority of the neutron dose is not coming straight down, but is coming from all directions due to the scatter of neutrons by the air, the ground around the tank, and the remainder of the tank itself! Kistiakowsky's stupidity is like trying to shield gamma radiation from fallout by wearing lead-soled shoes, in the mistaken belief that the hazard is due to fallout under your feet:

'Shielding a tank crew against neutrons is an enormously complicated problem. It is not solved by simply placing the shield over the crew compartment. By the time the neutrons reach the tank, they are bouncing around in all directions, and to protect the crew properly, the shielding will have to be placed around the sides of the crew compartment as well. As a consequence, the shielding weight begins to pile up: to a much greater level than Kistiakowsky realizes. ... The tank's mobility would be cut appreciably, as would the ability to swing the turret around to fire at acquired targets. In fact, were the tank to be shielded to a degree where the radiation was no longer the primary threat ... the added weight would cripple the tank's combat effectiveness.'

Another wild claim against the neutron bomb, made by Dr Herbert Scoville, Jr., which Cohen debunks (page 140), is that tank crews who are lethally irradiated will fight a 'Kamikaze' attack even more efficiently that they were fighting before, despite having radiation sickness. Cohen points out that they will not know exactly what their neutron dose is in a combat situation, and in any case the symptoms of radiation sickness will prevent their efficient execution of military functions.

Cancer and genetic effects are another hoax which was levelled against the neutron bomb: lethally irradiated people don't get cancer (as we shall see, Cohen shows that the effects of radiation sickness are no worse than other lethal combat injuries in modern conventional warfare due to organ damage, burns effects, and so on). In any case, no excess of genetic effects occurred in Hiroshima and Nagasaki as compared to a matched non-exposed control group. For all types of cancers, radiation has only contributed a small fraction of the cancer in survivors, most of which is natural cancer, as shown by comparison with the matched non-exposed control group. Claims that neutron bomb radiation is 'inhumane' ignore the comparison with the organ damage consequences by conventional nuclear weapons (as well as with conventional weapons, which rip organs to pieces, burn, crush and so on), and they ignore the primary purpose of the neutron bomb is to deter an aggressor.

Cohen further points out (pages 153-5) that two radiation accident victims who survived 400-600 cGy air doses (300-450 bone marrow doses): 'were back to normal some number of weeks [discharge from hospital at 2 and 6 weeks, respectively, and full recovery of strength at 10 weeks postexposure] after their accidents. They bore no scars from their mishaps (apparently not even emotional scars) and were able to pick up where they left off when they were irradiated. As to how these aftermaths compare with those resulting from being wounded by conventional weapons, if one so desires you can find out by visiting the nearest Veterans Administration hospital.'

On 11 November 1981, the Los Angeles Times printed an article called 'Neutron Weapons: an Agonising Death (I've seen it)', by Professor J. Garrott Allen at Stanford University Medical School, falsely claiming that the death of Dr Louis Slotin 9 days after a criticality accident in May 1946 indicates the radiation effects of a neutron bomb: 'The production of neutron weapons is probably as immoral a concept as human minds have yet devised.' Cohen debunks Allen on pages 156-7: Dr Slotin was touching a plutonium bomb core with his bare hands when he made it supercritical, so he got terrible localized exposures to his hands and arms, which were way higher than the doses you can get from a neutron bomb. This is why Dr Slotin had the painful radiation burns which Allen observed in treating him. Allen was dishonest in claiming that those radiation burns were analogous to neutron bomb exposures. In any case: 'Allen never mentioned the terrible burns that can result from ... the heat from fission battlefield nuclear weapons.'

On 10 September 1981, two months before Allen's notoriously inaccurate article was published, Cohen had written to the Secretary of Energy James B. Edwards, asking:

'Why is it, Mr Secretary, that after more than four years of intense, often acrimonious and almost always highly emotional, debate over the neutron bomb, the government has never put out an official statement to dispel the distorted technical charges which have been made about the weapon's effectiveness and alleged immorality? It seems to me that had this been done at the start, today we would not have the same anti-nuclear scientists making the same distorted charges; leaving the American people as confused as ever - and probably the Europeans as well.

'I would strongly suggest that DOE and DOD get together (as they did some 30 years ago, when they first issued The Effects of Nuclear Weapons to responsibly inform the American people what nuclear weapons were all about) and provide an official document spelling out the true facts of the issue.' (As we shall see, the declassification of Capabilities of Nuclear Weapons is a step in that direction.)




Above: the 14.8 megatons Castle-Bravo nuclear surface burst on 1 March 1954 at Bikini Atoll, about 20 seconds after detonation. If the Pentagon wanted to kill civilians in a nuclear war, it would have planned to use such nuclear explosions, instead of moving downward to the deterrence of 1 kt neutron bombs burst at 500 metres over Warsaw Pact tank concentrations.

Above: damage to the personnel camp 17 miles away (on the other side of Bikini Atoll), from the 14.8 megatons Castle-Bravo test.


Above: the 3.8 megatons (50% fission) Redwing-Cherokee nuclear test air burst on 21 May 1956 at an altitude of 4,350 feet over Bikini Atoll, having been dropped from a B-52 bomber (the bomb was 34.5 inches wide, 136 inches long, and weighed 6867 lb). This is another way to produce maximum civilian casualties, in contrast to the neutron bomb.


I briefly reviewed the tremendous and excellent autobiography of Sam Cohen, Shame, earlier (click here). The Third Edition has now been released (click here for free PDF book file), with some obvious improvements. Conrad Schneiker kindly emailed the news, stating: 'The third edition features a new overview and postscript chapter by Charles Platt, plus an extremely provocative change of title. (I advised against something so outrageous, but you know how outraged Sam is about current events.)'

In my earlier review I focussed on how the Pope came around to the neutron bomb as a moral step forward in reducing collateral civilian damage in modern warfare by using nuclear weapons with suppressed blast, thermal and delayed effects, but enhanced penetrating initial radiation. The neutron bomb is like the Ark of the Covenant, with its peaceful, deterring rays. Cohen was justifiably awarded the Vatican Peace Medal for his courageous work.
I think the changes are sensible to make any impact whatsoever. There is a lot of coercion for everyone, even the most sensible people in the world - like President George W. Bush - to obey the rules of "Group-Think" (definition: click here). Hence some strong arguments are required to make headway.

What is outrageous is the widely-held belief that dirty, high yield (300-400 kt or whatever) warheads stocked today, which would have fairly massive fallout, blast and thermal implications, are more moral to stockpile as a deterrent than 1-10 kt neutron bombs which are designed for air burst detonation to avert all local fallout hazards, and which release relatively little blast and heat flash since 80% of the energy from deuterium-tritium fusion is released as neutrons.

Obviously there is some fission also involved to start off the clean fusion reaction (but that is trivial for a yield of 1-2 kt, even if burst on the surface or shallow underground to maximise fallout, click here for experimental proof from nuclear tests surface burst, and here for shallow underground test data), and there is also the issue that some soldiers massed in fortifications or fighting vehicles will be neutron targets, but that's the only way to deter them. The public don't understand the fact that the neutron bomb has no collateral damage:

Cohen points out that the neutron bomb doesn't have the collateral damage of fallout, blast and heat effects that occurred in Hiroshima, but enhanced neutron flash radiation:

'in about a thousandth of a second it will seriously irradiate enemy soldiers (in tanks, self-propelled artillery vehicles, armored personnel carriers, in field bunkers, and most other places where they may be) out to a distance of about half to three-quarters of a mile for a warhead yield of a kiloton... Roughly half will die, most rather quickly from shock to the central nervous system. ... What doesn’t it do? Well, for start-offs, when the war is over the civilian areas — villages, towns, cities — will be in just about the shape they were in before it started. There will be no lingering radioactivity [residual doses from neutron induced activity in soil are insignificant compared to the flash dose of neutrons, and it decays quickly as in Hiroshima] to prevent occupation of these areas; in fact, they can be reentered almost immediately. (Compare this with every major war we’ve fought in this century, with what I saw in Seoul that affected me so deeply.)

'As for the enemy soldiers, the bad guys, who during a war we make out to be as barbaric as the troops of Attila the Hun (they usually are), those that die are dead; but that’s always been the main objective in battlefield conflict — to kill. As to how they die, which hasn’t been of real concern in conventional war, all I can say is I doubt whether the agony an irradiated soldier goes through in the process of dying is any worse than that produced by having your body charred to a crisp by napalm, your guts being ripped apart by shrapnel, your lungs blown in by concussion weapons, and all those other sweet things that happen when conventional weapons (which are preferred and anointed by our official policy) are used.' (Shame, online edition, p. 130.) - from earlier review.

http://en.wikipedia.org/wiki/Groupthink:

'Groupthink is a mode of thought whereby individuals intentionally conform to what they perceive to be the consensus of the group. Groupthink may cause the group (typically a committee or large organization) to make bad or irrational decisions which each member might individually consider to be unwise.

'The term was coined in 1952 by William H. Whyte in Fortune[1]:

'Groupthink ... is a rationalized conformity — an open, articulate philosophy which holds that group values are not only expedient but right and good as well. [2]

'Irving Janis, who did extensive work on the subject, defined it as:

'A mode of thinking that people engage in when they are deeply involved in a cohesive in-group, when the members' strivings for unanimity override their motivation to realistically appraise alternative courses of action. [3]

'Irving Janis originally studied how groupthink affected the Pearl Harbor bombing, the Vietnam War, and the Bay of Pigs Invasion.

'... the Bay of Pigs Invasion as the archetype of the groupthink phenomenon. ... the decision to execute this disastrous military campaign was made with almost unanimous agreement by President John F. Kennedy and his advisors. These advisors were, almost without exception, very similar in background to the President ... General David M. Shoup, Commandant of the Marine Corps at the time and not part of the privileged group, predicted failure and enormous casualties for the invasion, and practically begged the President not to undertake it. Shoup's professional advice was ignored ... with disastrous results. ... In 2004, the US Senate Intelligence Committee's Report on the U.S. Intelligence Community's Prewar Intelligence Assessments on Iraq blamed groupthink for failures to correctly interpret intelligence relating to Iraq's weapons of mass destruction capabilities ...

'Causes and symptoms of groupthink

'Janis's "antecedent conditions" likely to encourage groupthink:

High stress from external threats with low hope of a better solution than the one offered by the leader(s)

High group cohesiveness

The persuasive strength of the group's leader

'His eight symptoms indicative of groupthink:

Illusion of invulnerability


Unquestioned belief in the inherent morality of the group

Collective rationalization of group's decisions

Shared stereotypes of outgroup, particularly opponents

Self-censorship; members withhold criticisms

Illusion of unanimity (see false consensus effect)

Direct pressure on dissenters to conform

Self-appointed "mindguards" protect the group from negative information

'His seven symptoms of a decision affected by groupthink:

Incomplete survey of alternatives

Incomplete survey of objectives

Failure to examine risks of preferred choice

Failure to re-appraise initially rejected alternatives

Poor information search

Selective bias in processing information at hand (see also confirmation bias)

Failure to work out contingency plans

'Social psychologist Clark McCauley's three conditions under which groupthink occurs:

Directive leadership

Homogeneity of members' social background and ideology

Insulation of the group from outside sources of information and analysis ...

'One mechanism which management consultants recommend to avoid groupthink is to place responsibility and authority for a decision in the hands of a single person who makes the decision in private and can turn to others for advice. Others advise that a preselected individual take the role of disagreeing with any suggestion presented, thereby making other individuals more likely to present their own ideas and point out flaws in others' and reducing the stigma associated with being the first to take negative stances (see Devil's Advocate).'

Groupthink is clearly on display in the manner that string theorists operate.

Extract from a previous post on this blog:

Appendix A of the July 2004 Commission EMP report quotes from Thomas C. Schelling's Foreword to Roberta Wohlstetter's book Pearl Harbor: Warning and Decision, Stanford UniversityPress, 1962, p. vii:

'[There is] a tendency in our planning to confuse the unfamiliar with the improbable. The contingency we have not considered looks strange; what looks strange is therefore improbable; what seems improbable need not be considered seriously.'

This is true. Even when Hitler mobilized 100 divisions at the Soviet Union's border in 1941, Stalin was dismissive of all reports of preparations being made by the Nazis to invade the Soviet Union (this was because of the Nazi-Soviet peace-pact of 1939, creating a false sense of security to the USSR). Herman Kahn has explained in On Thermonuclear War (1960) how Pearl Harbor, Oahu, Hawaii (appropriately by coincidence also the centre of unpredicted EMP damage in the 1962 Starfish nuclear test) was supposedly immune from attack, because it was shallower than the textbook-stated minimum water depth for a torpedo. The Japanese simply made special torpedoes to use in the attack on the U.S. Pacific Fleet in 1941. (Even when America received advanced warning of the attack, its wishful thinking simply dismissed the warning as an error, so no warning was passed on, and the scale of the tragedy was maximised.)

From another earlier post:

In a controlled sample of 36,500 survivors, 89 people got leukemia over a 40 year period, above the number in the unexposed control group. (Published in Radiation Research volume 146:1-27, 1996.)


Over 40 years, in 36,500 survivors monitored, there were 176 leukemia deaths which is 89 more than the control (unexposed) group got naturally. There were 4,687 other cancer deaths, but that was merely 339 above the number in the control (unexposed) group, so this is statistically a much smaller rise than the leukemia result.

Natural leukemia rates, which are very low in any case, were increased by 51 % in the irradiated survivors, but other cancers were merely increased by just 7 %.

Adding all the cancers together, the total was 4,863 cancers (mainly natural), which is just 428 more than the unexposed control group. Hence, the total increase over the natural cancer rate was 9 %, spread over 40 years.

(Compare these scientific facts to popular fiction in newspapers and widely published political books 'explaining' the horrific effects of nuclear weapons compared to other weapons, which claims there were 100,000 or 200,000 cancers. The real figure is 428.)

From the review of the 2nd edition of Sam Cohen's book:

More on the testing of clean tactical nuclear weapons as low air bursts here (for true air bursts there is no early fallout at all, apart from thunderstorms when it goes straight down the drain anyhow and is shielded underground - it is better to have the fallout underground than people sheltering underground!), surface bursts here, here and here, and shallow underground bursts (for earth-penetrator effects; destruction of buried targets without collateral blast and thermal radiation) see here (scroll down on to section headed 'ARE EARTH PENETRATORS A CLEAN ALTERNATIVE TO HIGH YIELD SURFACE BURST NUCLEAR WEAPONS?'). For it's inclusion by Philip J. Dolan in Capabilities of Nuclear Weapons EM-1, and by Samuel Glasstone in an article in Encarta 97, see here.

A neutron bomb with a thick lead casing will constitute a potential earth-penetrator with greatly suppressed air blast, heat flash, and fallout. The energy of the neutrons will be turned into ground shock effects as they are scattered ('thermalized' to the ambient temperature in the explosion) by the thick casing. The thick casing will pass on ground shock efficiently, using the mechanism discovered by Brode and Bjork of RAND Corp in 1960: 'the primary cause of cratering for such an explosion is not "airslap," as previously suggested, but rather the direct action of the energetic bomb vapors.'

There are therefore numerous uses for neutron bombs in deterring war without risking indiscriminate collateral destruction and the massacre of civilians in the event of an explosion. The 'alternative' is high yield stockpiled warheads!

Update: Samuel T. Cohen, inventor of the neutron bomb, has died



Seen in 1999, Sam Cohen holds up a peace medal given to him by Pope John Paul I. He designed the neutron bomb with just pencil, paper and a slide rule. (San Jose Mercury News)

By Thomas H. Maugh II, Los Angeles Times
December 2, 2010

LOS ANGELES TIMES, Samuel T. Cohen dies at 89; inventor of the neutron bomb

... President Reagan ordered 700 neutron warheads built to oppose the massive Soviet tank force that had been strategically positioned in Eastern Europe. He viewed the bomb as the only tactical weapon that could effectively stop the tanks without also destroying much of the continent. The weapons were later dismantled in the face of widespread protests and the disintegration of the Soviet Union. ...

Samuel Theodore Cohen was born in Brooklyn, New York, on Jan. 25, 1921, to Austrian Jews who migrated to the United States by way of Britain. When he was 4, the family moved to Los Angeles, where his father worked as a carpenter on movie sets. Young Samuel suffered allergies, eye problems and other ailments, and his mother put him on a rigidly controlled diet, regular purges and daily ice-water showers to toughen him up, and fed him so much carrot juice that his skin was often yellow.

A brilliant student, he studied physics at UCLA, receiving a bachelor's degree in 1943. After joining the Army, he was posted to MIT for advanced training in physics and math, then selected for work on the Manhattan Project. Although he never received a doctoral degree, he calculated neutron densities on Fat Man, the bomb that was dropped on Nagasaki, Japan.

After World War II, he joined the RAND Corp. in Santa Monica and spent most of his career there. He said the inspiration for the neutron bomb was a 1951 visit to Seoul, which had been largely destroyed in the Korean War. In his memoir, he wrote: "If we are going to go on fighting these damned fool wars in the future, shelling and bombing cities to smithereens and wrecking the lives of their inhabitants, might there be some kind of nuclear weapon that could avoid all this?"

He designed the neutron bomb using pencil, paper and a slide rule given to him by his father for his 15th birthday.

See also the New York Times,
Samuel T. Cohen, Neutron Bomb Inventor, Dies at 89
By ROBERT D. McFADDEN
Published: December 1, 2010

Samuel T. Cohen, the physicist who invented the small tactical nuclear weapon known as the neutron bomb, a controversial device designed to kill enemy troops with subatomic particles but leave battlefields and cities relatively intact, died on Sunday at his home in Los Angeles. He was 89.

... He insisted that many critics misunderstood or purposely misrepresented his ideas for political, economic or mercenary reasons. ...

A graduate of the University of California, Los Angeles, Mr. Cohen was recruited while in the Army in World War II for the Manhattan Project, which developed the first atomic bomb at Los Alamos, N.M. After the war, he joined the RAND Corporation and in 1958 designed the neutron bomb as a way to strike a cluster of enemy forces while sparing infrastructure and distant civilian populations.

Fired via a missile or an artillery shell and detonated a quarter-mile above ground, his bomb limited death to an area less than a mile across, avoiding wider indiscriminate slaughter and destruction. ... its neutrons dissipated quickly, leaving no long-term contamination that could render entire regions uninhabitable for decades. ...

“It’s the most sane and moral weapon ever devised,” he said in September in a telephone interview for this obituary. “It’s the only nuclear weapon in history that makes sense in waging war. When the war is over, the world is still intact.”

Samuel Theodore Cohen was born in Brooklyn on Jan. 25, 1921, to Lazarus and Jenny Cohen, Austrian Jews who had migrated to the United States by way of Britain. His father was a carpenter and his mother a housewife who rigidly controlled family diets and even breathing habits (believing it unhealthy to breathe through the mouth). The boy had allergies, eye problems and other ailments, and for years was subjected to daily ice-water showers to toughen him up.

The family moved to Los Angeles when he was 4. He was a brilliant student at public schools and U.C.L.A., where he graduated in 1943 with a physics degree. He joined the wartime Army and was posted to the Massachusetts Institute of Technology for advanced training in mathematics and physics.

In 1944 he was tapped for the Manhattan Project to analyze radioactivity in nuclear fission. He worked on Fat Man, the bomb dropped on Nagasaki in 1945, days after Little Boy destroyed Hiroshima.

Mr. Cohen joined RAND in Santa Monica in 1947 and 11 years later designed the neutron bomb as a consultant to the Lawrence Livermore National Laboratory.

His books included “Tactical Nuclear Weapons: An Examination of the Issues” (1978); “The Neutron Bomb: Political, Technological and Military Issues” (1978); “Checkmate on War” (1980); “The Truth About the Neutron Bomb” (1983); “We Can Prevent World War III” (1985); and “Nuclear Weapons, Policies and the Test Ban Issue” (1987). His memoir, “Shame: Confessions of the Father of the Neutron Bomb,” was published on the Internet in 2000.