I'm sharing this because of the report of a Neutron Bomb going off in Yemen.
Neutron bomb
From Wikipedia, the free encyclopedia
| Standard | Enhanced | |
|---|---|---|
| Blast | 50% | 40%[1] or as low as 30%[2] |
| Thermal energy | 35% | 25%[1] or as low as 20%[2] |
| Instant radiation | 5% | 30[1]–45% |
| Residual radiation | 10% | 5%[1] |
Compared to a pure fission bomb with an identical explosive yield, a neutron bomb would emit about ten times[4] the amount of neutron radiation. In a fission bomb, at sea level, the total radiation pulse energy which is composed of both gamma rays and neutrons is approximately 5% of the entire energy released; in the neutron bomb it would be closer to 40%. Furthermore, the neutrons emitted by a neutron bomb have a much higher average energy level (close to 14 MeV) than those released during a fission reaction (1–2 MeV).[5] Technically speaking, all low yield nuclear weapons are radiation weapons, that is including the non-enhanced variant. Up to about 10 kilotons in yield, all nuclear weapons have prompt neutron radiation[6] as their most far reaching lethal component, after which point the lethal blast and thermal effects radius begins to out-range the lethal ionizing radiation radius.[7][8][9] Enhanced radiation weapons also fall into this same yield range and simply enhance the intensity and range of the neutron dose for a given yield.
Contents
History & deployment to present
Conception of the neutron bomb is generally credited to Samuel T. Cohen of the Lawrence Livermore National Laboratory, who developed the concept in 1958.[10] Testing was authorized and carried out in 1963 at an underground Nevada test facility.[11] Development was subsequently postponed by President Jimmy Carter in 1978 following protests against his administration's plans to deploy neutron warheads to ground forces in Europe.[12] On November 17, 1978, in a test the USSR detonated its first similar-type bomb.[13] President Ronald Reagan restarted production in 1981.[12] The Soviet Union began a propaganda campaign against the US's neutron bomb in 1981 following Reagan's announcement. In 1983 Reagan then announced the Strategic Defense Initiative, which surpassed neutron bomb production in ambition and vision and with that the neutron bomb quickly faded from the center of the public's attention.[13]Three types of enhanced radiation weapons (ERW) were built by the United States.[14] The W66 warhead, for the anti-ICBM Sprint missile system, was deployed in 1975 and retired the next year, along with the missile system. The W70 Mod 3 warhead was developed for the short-range, tactical Lance missile, and the W79 Mod 0 was developed for artillery shells. The latter two types were retired by President George H. W. Bush in 1992, following the end of the Cold War.[15][16] The last W70 Mod 3 warhead was dismantled in 1996,[17] and the last W79 Mod 0 was dismantled by 2003, when the dismantling of all W79 variants was completed.[18]
In addition to the two superpowers, France and China are known to have tested neutron or enhanced radiation bombs. France conducted an early test of the technology in 1967[19] and tested an "actual" neutron bomb in 1980.[20] China conducted a successful test of neutron bomb principles in 1984 and a successful test of a neutron bomb in 1988. However, neither country chose to deploy the neutron bomb. Chinese nuclear scientists stated prior to the 1988 test that China had no need for the neutron bomb, but it was developed to serve as a "technology reserve," in case the need arose in the future.[21]
Although no country is currently known to deploy them in an offensive manner, all thermonuclear dial-a-yield warheads that have about 10 kiloton and lower as one dial option, with a considerable fraction of that yield derived from fusion reactions, can be considered capable of being neutron bombs in actuality if not in name. The only country definitively known to deploy dedicated (that is, not Dial-a-yield) neutron warheads for any length of time is Russia, which inherited the USSRs neutron warhead equipped ABM-3 Gazelle missile program, this Anti-ballistic missile (ABM) system contains at least 68 neutron warheads of yield 10 kiloton and it has been in service since 1995, with inert missile testing approximately every other year since then (2014). The system is designed to destroy incoming "endo-atmospheric" level nuclear warheads aimed at Moscow etc. and is the lower-tier/ last umbrella of the A-135 anti-ballistic missile system (NATO reporting name: ABM-3).[22]
By 1984, according to Mordechai Vanunu, Israel was mass-producing neutron bombs.[23] A number of analysts believe that the Vela incident was an Israeli neutron bomb experiment.[24]
Considerable controversy arose in the U.S. and Western Europe following a June 1977 Washington Post exposé describing U.S. government plans to purchase the bomb. The article focused on the fact that it was the first weapon specifically intended to kill humans with radiation.[25][26] Lawrence Livermore National Laboratory director Harold Brown and Soviet General Secretary Leonid Brezhnev both described the neutron bomb as a "capitalist bomb", because it was designed to destroy people while preserving property.[27][28] Science fiction author Isaac Asimov also stated that "Such a neutron bomb or N bomb seems desirable to those who worry about property and hold life cheap."[29]
Use
Neutron bombs are purposely designed with explosive yields lower than other nuclear weapons. Since neutrons are absorbed by air,[6] neutron radiation effects drop off very rapidly with distance in air, there is a sharper distinction, as opposed to thermal effects, between areas of high lethality and areas with minimal radiation doses.[3] All high yield (more than ~10 kiloton) "neutron bombs", such as the extreme example of a device that derived 97% of its energy from fusion, the 50 megaton Tsar Bomba, are not able to radiate sufficient neutrons beyond their lethal blast range when detonated as a surface burst or low altitude air burst and so are no longer classified as neutron bombs, thus limiting the yield of neutron bombs to a maximum of about 10 kilotons. The intense pulse of high-energy neutrons generated by a neutron bomb are the principal killing mechanism, not the fallout, heat or blast.The inventor of the neutron bomb, Samuel Cohen, criticized the description of the W70 as a "neutron bomb" since it could be configured to yield 100 kilotons:
the W-70 ... is not even remotely a "neutron bomb." Instead of being the type of weapon that, in the popular mind, "kills people and spares buildings" it is one that both kills and physically destroys on a massive scale. The W-70 is not a discriminate weapon, like the neutron bomb—which, incidentally, should be considered a weapon that "kills enemy personnel while sparing the physical fabric of the attacked populace, and even the populace too."[30]
The Soviet/Warsaw pact invasion plan, "Seven Days to the River Rhine" to seize West Germany.
Under such a scenario, neutron bombs, according to their inventor,
would hopefully blunt the Warsaw pact tank, and more thinly armored BMP-1
thrusts, without causing as much damage to the people and
infrastructure of Germany as alternative higher fission fraction &
higher explosive yield tactical nuclear weapons would.[31] They would likely be used if the mass conventional weapon NATO REFORGER response to the invasion had yet to find time to be organized or found ineffective in battle.
Neutron bombs could be used as strategic anti-ballistic missile weapons,[33] or as tactical weapons intended for use against armored forces. The neutron bomb was originally conceived by the U.S. military as a weapon that could stop massed Soviet armored divisions from overrunning allied nations without destroying the infrastructure of the allied nation.[31][34] As the Warsaw Pact tank strength was over twice that of NATO, and Soviet Deep Battle doctrine was likely to be to use this numerical advantage to rapidly sweep across continental Europe if the Cold War ever turned hot, any weapon that could break up their intended mass tank formation deployments and force them to deploy their tanks in a thinner, more easily dividable manner,[31] would aid ground forces in the task of hunting down solitary tanks and firing anti-tank missiles upon them,[35] such as the contemporary M47 Dragon and BGM-71 TOW missiles.
Effects
Wood frame house in 1953 nuclear test, 5 psi overpressure, complete collapse
of radiation,[36] which would require exploding large numbers of them to blanket the enemy forces, would also destroy all normal civilian buildings in the same immediate area ~600 meters,[36][37] and via neutron activation it would make many building materials in the city radioactive, such as Zinc coated steel/galvanized steel(see Area denial use below). Although at this ~600 meter distance the 4-5 PSI blast overpressure would cause very few direct casualties as the human body is resistant to sheer overpressure, the powerful winds produced by this overpressure are capable of throwing human bodies into objects or throwing objects-including window glass at high velocity, both with potentially lethal results, rendering casualties highly dependent on surroundings, including on if the building they are in collapses.[38] The pulse of neutron radiation would cause immediate and permanent incapacitation to unprotected outdoor humans in the open out to 900 meters,[4] with death occurring in one or two days. The lethal dose(LD50) of 600 Rads would extend to about 1350–1400 meters for those unprotected and outdoors,[36] where approximately half of those exposed would die of radiation sickness after several weeks. However a human residing within, or is simply shielded by at least 1 of the aforementioned concrete buildings with walls and ceilings 30 centimeters/12 inches thick, or alternatively of damp soil 24 inches thick, the neutron radiation exposure would be reduced by a factor of 10.[39][40]
Furthermore the neutron absorption spectra of air is disputed by some authorities and depends in part on absorption by hydrogen from water vapor. It therefore might vary exponentially with humidity, making neutron bombs immensely more deadly in desert climates than in humid ones.[36]
Questionable effectiveness in modern anti-tank role
See also: Centurion Tank § Nuclear tests and Neutron transport
The Neutron cross section/ absorption probability in barns of the two natural Boron
isotopes found in nature (top curve is for 10B and bottom curve for
11B. As neutron energy increases to 14 MeV, the absorption
effectiveness, in general, decreases. Therefore for boron containing
armor to be effective, fast neutrons must first be slowed by another
element by neutron scattering.
A composite high density concrete, or alternatively, a laminated Graded Z shield, 24 units thick of which 16 units are iron and 8 units are polyethylene containing boron (BPE) and additional mass behind it to attenuate neutron capture gamma rays is more effective than just 24 units of pure iron or BPE alone, due to the advantages of both iron and BPE in combination. Iron is effective in slowing down/scattering high-energy neutrons in the 14-MeV energy range and attenuating gamma rays, while the hydrogen in polyethylene is effective in slowing down these now slower fast neutrons in the few MeV range, and boron 10 has a high absorption cross section for thermal neutrons and a low production yield of gamma rays when it absorbs a neutron.[43][44][45][46] The Soviet T72 tank, in response to the neutron bomb threat, is cited as having fitted a boronated,[47] polyethylene liner, which has had its neutron shielding properties simulated.[40][48]
The radiation weighting factor
for neutrons of various energy has been revised over time and certain
agencies have different weighting factors, however despite the variation
amongst the agencies, from the graph, for a given energy, A Fusion neutron(14 MeV) although more energetic, is less biologically deleterious than a Fission generated neutron or a Fusion neutron slowed to that energy, ~0.8 MeV .
Use against ballistic missiles
As an anti-ballistic missile weapon, the first fielded ER warhead, the W66, was developed for the Sprint missile system as part of the Safeguard Program to protect United States cities and missile silos from incoming Soviet warheads by damaging their electronic components with the intense neutron flux.[33] Ionization greater than 5,000 rads in silicon chips delivered over seconds to minutes will degrade the function of semiconductors for long periods.[54] Due to the rarefied atmosphere encountered high above the earth at the most likely intercept point of an incoming warhead by a neutron bomb/warhead, whether it be the retired Sprint missile's W66 neutron warhead or the still in service Russian counterpart, the ABM-3 Gazelle, at the Terminal phase point(10–30 km) of the incoming warheads flight, the neutrons generated by a Mid to High-altitude nuclear explosion(HANE) have an even greater range than that encountered after a low altitude air burst, where there is a lower density of air molecules that produces, by comparison, an appreciable reduction in the air shielding effect/half-value thickness.However, although this neutron transparency advantage attained only increases at increased altitudes, neutron effects lose importance in the exoatmospheric environment, being overtaken by the range of another effect of a nuclear detonation, at approximately the same altitude as the end of the incoming missile's boost phase(~150 km), ablation producing soft x-rays are the chief nuclear effects threat to the survival of incoming missiles and warheads rather than neutrons.[55] A factor exploited by the other warhead of the Safeguard Program, the enhanced (X-ray) radiation W71 and its USSR/Russian counterpart, the warhead on the A-135 Gorgon missile.
Another method by which neutron radiation can be used to destroy incoming nuclear warheads is by serving as an intense neutron generator and to thus initiate fission in the incoming warheads fissionable components by fast fission, potentially causing the incoming warhead to prematurely detonate in a Fizzle if within sufficient proximity, but in most likely interception ranges, requiring only that enough fissionable material in the warhead fissions to interfere with the functioning of the incoming warhead when it is later fuzed to explode(see related physics:Subcritical reactor).
Lithium-6 Hydride("Li6H") is cited as being used as a countermeasure to reduce the vulnerability/"harden" nuclear warheads from the effects of externally generated neutrons.[56][57] Radiation hardening of the warheads electronic components as a countermeasure to high altitude neutron warheads, somewhat reduces the range that a neutron warhead could successfully cause an unrecoverable glitch by the TREE(Transient Radiation effects on Electronics) mechanism.[58][59]
Use as an area denial weapon
In November 2012, during the planning stages of Operation Hammer of God, it was suggested by a British parliamentarian that multiple enhanced radiation reduced blast (ERRB) warheads could be detonated in the mountain region of the Afghanistan/Pakistan border to prevent infiltration.[60] He proposed to warn the inhabitants to evacuate, then irradiate the area, making it unusable and impassable.[61] Used in this manner, the neutron bomb(s), regardless of burst height, would release neutron activated casing materials used in the bomb, and depending on burst height, create radioactive soil activation products.In much the same fashion as the area denial effect resulting from fission product (the substances that make up the majority of fallout) contamination in an area following a conventional surface burst nuclear explosion, as considered in the Korean War by Douglas MacArthur, it would thus be a form of Radiological warfare - with the difference that neutron bombs produce 1/2, or less, of the quantity of fission products when compared to the same-yield pure fission bomb. Radiological warfare with neutron bombs that rely on fission primaries would therefore still produce fission fallout, albeit a comparatively "cleaner" and shorter lasting version of it in the area if air bursts were utilized, as little to no fission products would be deposited on the direct immediate area, instead becoming diluted global fallout.
However the most effective use of a neutron bomb with respect to area denial would be to encase it in a thick shell of material that could be neutron activated, and use a surface burst. In this manner the neutron bomb would be turned into a "salted bomb", a case of Zinc-64, produced as a byproduct of depleted zinc oxide enrichment, would for example probably be the most attractive from a military point of view, as when activated the Zinc-65 that is created is a gamma emitter, with a half life of 244 days.[62]
Maintenance
Neutron bombs/warheads require considerable maintenance for their capabilities, requiring some tritium for fusion boosting[citation needed] and tritium in the secondary stage (yielding more neutrons), in amounts on the order of a few tens of grams[63] (10–30 grams[64] estimated). Because tritium has a relatively short half-life of 12.32 years (after that time, half the tritium has decayed), it is necessary to replenish it periodically in order to keep the bomb effective. (For instance: to maintain a constant level of 24 grams of tritium in a warhead, about 1 gram per bomb per year[65] must be supplied.) Moreover, tritium decays into helium-3, which absorbs neutrons[66] and will thus further reduce the bomb's neutron yield.See also
- Atomic demolition munitions - similar strategic use, low yield nuclear weapons.
- Neutron activation
- Neutron transport
- Nuclear fallout
- Nuclear strategy
- Nuclear warfare
- Nuclear weapon design
- W54
References
- When absorbing neutrons, helium-3 produces back some tritium, but it comes too late in the reaction for fusion boosting and doesn't compensate for the decayed tritium missing at the start of the reaction.
Further reading
- Cohen, Sam, The Truth About the Neutron Bomb: The Inventor of the Bomb Speaks Out, William Morrow & Co., 1983, ISBN 0-688-01646-4
- Cohen, Sam, F*** You! Mr. President: Confessions of the Father of the Neutron Bomb, Xlibris Corporation, 2000
External links
- Strategic Implications of Enhanced Radiation Weapons
- Nuclear Files.org Definition and history of the neutron bomb
- Creator of Neutron Bomb Leaves an Explosive Legacy
- The Woodrow Wilson Center's Nuclear Proliferation International History Project or NPIHP is a global network of individuals and institutions engaged in the study of international nuclear history through archival documents, oral history interviews and other empirical sources.
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.
Jimmy Carter's successor, Ronald Reagan, changed US policy and gave the order for the production of neutron warheads to start in 1981. ...
With the fall of the Berlin Wall and the end of communism as we knew it, the Bush administration moved to dismantle all of our tactical nuclear weapons, including the Reagan stockpile of neutron bombs. In Cohen's mind, America was brought back to Square One. Without tactical weapons like the neutron bomb, America would be left with two choices if an enemy was winning a conventional war: surrender, or unleash the holocaust of strategic nuclear weapons.
Nuclear weapon-generated X-rays are the chief threat to the survival of strategic missiles in-flight above the atmosphere and to satellites...The Neutron and gamma ray effects dominate at lower altitudes where the air absorbs most of the X-rays.
Due to moderating ability and light weight, used to harden weapons against outside neutron fluxes (especially in combination with Li-6)...The very high cross section of this reaction for thermalized neutrons, combined with the light weight of the Li-6 atom, make it useful in the form of lithium hydride for hardening of nuclear weapons against external neutron fluxes.
The fact that Li6H is used in unspecified weapons for hardening
Neutron bomb - Wikipedia, the free encyclopedia
en.wikipedia.org/wiki/Neutron_bombCachedA neutron bomb, officially known as one type of Enhanced Radiation Weapon, is a low yield fission-fusion thermonuclear weapon (hydrogen bomb) in which the burst of ...
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