randy@ms.uky.edu (Randy Appleton) (10/29/90)
From: Randy Appleton <randy@ms.uky.edu> In article <43034@eerie.acsu.Buffalo.EDU> v064lnev@ubvmsd.cc.buffalo.edu writes: >I have heard several remarks about using nuclear weapons, and all of them have >been systematically shot down for but one reason - no one wants the lingering >radiation from a nuclear explosion. I believe this is a very valid reason, and >I respect it. But it's not the only one. The moral and political implications of first use are enormous. And even if you have no moral scruples, the political implications are still enormous. huge. >However, I believe we have one other option at our disposal. I >believe it is called, the Neutron Bomb. This is a bomb unlike any other, one >that the U.S. military has previously developed, and placed on the back burner. >I shall explain the very interesting aspects of such a weapon: > > * Once delivery of this bomb has been successful, it's effects evade > all senses. There is no explosion, as this is not the principle > behind its function. Er, no. Not at all. A Neutron Bomb is just an "enhanced radation nuclear warhead". In other words, it is a nuclear bomb designed to release more prompt radiation (netrons), and less thermal energy (blast) than normal. In perticular, the lethal radius of the prompt radiation is much bigger than the blast. But there is still a nuclear-weapon sized blast! The original idea was as a weapon to stop Soviet tank columns in Western Europe. A bomb big enough to kill an armored tank at radius X would destry buildings at a radius much bigger than X, and Western Europe is rather crowded with cities. But, by releasing lots of fast (as opposed to thermal) neutrons, the outer skin of the armor would be hit by lots of fast neutrons, and then release even more thermal (means 'slow' to a phyicist) neutrons, and irradiate the crew, killing them. But, there is still an atomic (A-bomb, not H-bomb) bomb at the center of the neutron bomb. > > * The bomb emits neutrons in all directions, effectivly killing all > organic life within its radius of effect. > > * Inorganic structures are not damaged with the use of this weapon. > Thus, the inhabitants of a city may be killed, but the city, itself, > will be undamaged. Well, wrong. Actually, there is a blast. > > * There is virtually no lingering radiation from the use of this weapon. > Thus, allowing troops to advance upon the site within a matter of > days, without any risk of radiation poisoning. Er, I'm not sure, but I doubt it. Think of all that radiation that gets released in the explosion, and then absorbed by the enviornment. I bet it generates some interesting isotopes. Would you be willing to visit the area? Also, there is a big difference between the amount of radation that an area can withstand an still allow troupes in the middle of war thru it, and the amount of radiation that an area can withstand and support permant occupancy! >Could not this weapon be facilitated in a most advantageous way? I believe >that this option should be considered before the use of other conventional >nuclear weapons. What think you? Also, I thought that we (America) decided *NOT* to build any. Does anyone know for sure? I'm adding sci.military to the distribution; the effects of the neutron bomb seems quite in their area! -Randy -- ============================================================================= My feelings on George Bush's promises: "You have just exceeded the gulibility threshold!" ============================================Randy@ms.uky.edu==================
jgd@gatech.edu (John G. DeArmond) (10/30/90)
From: rsiatl!jgd@gatech.edu (John G. DeArmond) randy@ms.uky.edu (Randy Appleton) writes: >From: Randy Appleton <randy@ms.uky.edu> >>However, I believe we have one other option at our disposal. I >>believe it is called, the Neutron Bomb. This is a bomb unlike any other, one >>that the U.S. military has previously developed, and placed on the back burner. >Er,no. Not at all. A Neutron Bomb is just an"enhanced radation nuclear warhead" >In other words, it is a nuclear bomb designed to release more prompt radiation >(netrons), and less thermal energy (blast) than normal. NO, NO, NO! Let's examine what an ER weapon really is. First, let's consider a typical conventional thermonuclear weapon. Conventional weapons are refered to as "fission-fusion-fission" weapons. That is, a fission trigger ignites a fusion intermediate stage whose primary purpose is to generate fast neutrons that then transmute the U-238 casing into fissional material and fissions it all in one fell swoop. The bulk of the energy delivered results from FISSION. The fusion intermediate stage can be thought of as a neutron multiplier. The ER weapon simply substitutes a heavy but non-fissionable casing for the U-238. Typically a tungsten alloy is used. Thus, the intense quantity of neutrons interact with the heavy casing and nearby air and the end result is a larger GAMMA radiation to blast ratio. I must correct one other point. Blast and thermal radiation damage have no relation to each other except that they both come from a common source. The thermal radiation pulse is completely over with by the time the blast (which travels at approximately the speed of sound) arrives. The destructive effects are also totally different, with thermal radiation causing primarily human burn casulties and fires while the blast causes structural damage. Obviously in an ER situation, the blast is to be minimized. There is no biological hazard with any weapon from neutrons at any range for which the gamma radiation would not overwhelm. The mean free path of neutrons of almost any conceivable energy in air is trivial compared to the radius of gamma hazard. Which, of course, is a fortunate effect. Gamma radiation delivers the desired killing effect and leaves no residual effects. Neutrons, on the other hand, activate a wide variety of materials, some such as cobalt tend to be rather pesky for a long period of time. Anyone with more than a passing interest in this subject should buy 2 books. First is "The effects of Nuclear Weapons" by Sam Glasstone, available from the US GPO for about $20. The second is "The making of the Atomic Bomb" (I forget the author.) The first book studies in great detail each of the major effects of nuclear weapons and provides one with the means to calculate them for a given yield. There is even a circular slide rule "bomb effects calculator" in a sleeve in the back of the book. John -- John De Armond, WD4OQC | "The truly ignorant in our society are those people Radiation Systems, Inc. | who would throw away the parts of the Constitution Atlanta, Ga | they find inconvenient." -me Defend the 2nd {emory,uunet}!rsiatl!jgd| with the same fervor as you do the 1st.
seeger@thedon.cis.ufl.edu (F. L. Charles Seeger III) (11/03/90)
From: seeger@thedon.cis.ufl.edu (F. L. Charles Seeger III) In article <1990Oct30.052109.6742@cbnews.att.com> rsiatl!jgd@gatech.edu (John G. DeArmond) writes: |NO, NO, NO! Let's examine what an ER weapon really is. First, let's consider |a typical conventional thermonuclear weapon. Conventional weapons are |refered to as "fission-fusion-fission" weapons. That is, a fission trigger |ignites a fusion intermediate stage whose primary purpose is to generate |fast neutrons that then transmute the U-238 casing into fissional material |and fissions it all in one fell swoop. The bulk of the energy delivered |results from FISSION. The fusion intermediate stage can be thought of |as a neutron multiplier. One of my former Nuclear Eng. profs had worked at LANL and had some exposure (no pun intended) to weapons design. It is my distinct recollection that the use of U-238 casing material is almost exclusively a Soviet practice. That is why Soviet warheads tend to be bigger and dirtier than American. Up to 80% of the warhead energy can come from this fission of U-238 by fast fusion neutrons (*not* by breeding and fissioning Plutonium-239). |The ER weapon simply substitutes a heavy but non-fissionable casing for |the U-238. Typically a tungsten alloy is used. Thus, the intense |quantity of neutrons interact with the heavy casing and nearby air and |the end result is a larger GAMMA radiation to blast ratio. Every explanation that I have heard indicates that the ER is a fisson bomb that has been purposely tuned to a low yeild. Most of the thermal/blast effects are generated in last generation or two of fast neutrons. These are tuned out to give, say, about 1% yield, but there is still a significant fast neutron flux from this 'dud' explosion. I would be very suprised if there was any lithium, deuterium or tritium in an ER warhead outside of the neutron trigger target. (The neutron trigger is used to initiate the explosion with a large neutron population, rather than wait for it to build up starting with spontaneous fissions. This makes better use of the limited amount of time things have to react, i.e. it makes a bigger boom. Since this trigger depends on DT reactions to generate fast neutrons, bombs acutally start with fusion first. So, you actually have up to four 'amplifier' stages. Lithium is used to breed tritium during the blast.) Also, the (limited) discussions that I have heard about ER radiation effects have centered exclusively on neutron exposure. I grant that there will be a lot of gamma, but I would like see some rough calculations to back up this assertion that the prompt gamma doses would predominate. I would not expect fast neutrons to so heavily activate the casing material so as to make this a more significant biological threat than all those neutrons themselves. There will also be significant X radiation (the blast does form an energetic plasma, after all), but the neutrons (being neutral particles) interacting with the casing shouldn't generate X radiation with lethality comparable to that of the neutrons themselves. I don't have any references immediately available to perform any 'back-of-the-envelope' calculations. -- Charles Seeger E301 CSE Building Office: +1 904 392 1508 CIS Department University of Florida Fax: +1 904 392 1220 seeger@ufl.edu Gainesville, FL 32611-2024
jgd@gatech.edu (John G. DeArmond) (11/06/90)
From: rsiatl!jgd@gatech.edu (John G. DeArmond) >From: seeger@thedon.cis.ufl.edu (F. L. Charles Seeger III) >One of my former Nuclear Eng. profs had worked at LANL and had some exposure >(no pun intended) to weapons design. >It is my distinct recollection that >the use of U-238 casing material is almost exclusively a Soviet practice. >That is why Soviet warheads tend to be bigger and dirtier than American. I likewise have had some "exposure" (understatement) to weapons design. I am at an unfortunate disadvantage in that I cannot repeat even publicly available information in some cases, lest it be inadvertently mixed with other data and lest my quoting public information give it credibility. Let me just say that you should consult the literature. Look particularly closely at literature concerning X-ray mirrors. We do indeed use U-238 but much differently than the Russians. >Every explanation that I have heard indicates that the ER is a fisson bomb >that has been purposely tuned to a low yeild. Most of the thermal/blast >effects are generated in last generation or two of fast neutrons. These >are tuned out to give, say, about 1% yield, but there is still a significant >fast neutron flux from this 'dud' explosion. Let me attack this supposition from several angles. First, tactical. The objective in using an ER weapon is to kill enemy soldiers and/or civilians but leave the infrastructure intact. Neutrons are wholly unsuitable for this task. Not only are fast neutrons poorly absorbed by human tissue, they have a nasty propensity to activate materials they impinge on. It specifically is NOT the objective to make the terrain a vast radioactive wasteland. Residual radiation should be as low a possible. This implies a very clean device whose output is primarily gamma rays, a form of energy ideally suited for killing lifeforms but not producing long term damage. Secondly, the mean free path for fast neutrons is relatively short. Most are dissipated via inelastic scattering with the resultant gamma ray emission. The probability of this interaction occuring varies logrithmically with the neutron energy. There is a very good discussion of this phenomena in "Introduction to Health Physics, Cember" on pages 127,8,9. Thirdly, the main conduit of energy from the device is via soft X-rays. These X-rays are emitted as thermal radiation from the recoil particles of the fission process whose equivalent thermal temperature corrisponds to radiation in the X-ray band. Rather than recite a lot of text, I'll refer you to "The Effects of Nuclear Weapons, Glasstone". >Also, the (limited) discussions that I have heard about ER radiation effects >have centered exclusively on neutron exposure. I grant that there will be >a lot of gamma, but I would like see some rough calculations to back up this >assertion that the prompt gamma doses would predominate. Again, the authority on the subject is "The Effects of Nuclear Weapons". Dr. Glasstone devotes scant space to neutrons as a biological hazard. He does supply the equations from which to calculate gamma yield at a given distance for a given device yield and a given slant angle. There is also a convenient circular slide rule "bomb effects calculator" device included in the back slipcover of the book. >I would not expect >fast neutrons to so heavily activate the casing material so as to make this >a more significant biological threat than all those neutrons themselves. >There will also be significant X radiation (the blast does form an energetic >plasma, after all), but the neutrons (being neutral particles) interacting >with the casing shouldn't generate X radiation with lethality comparable to >that of the neutrons themselves. I don't have any references immediately >available to perform any 'back-of-the-envelope' calculations. Again, not true. The fireball which creats the blast wave is itself formed from the effect of soft x-rays being emitted from the weapon with an intensity sufficient to apply several hundred thousand PSI of pressure to the surrounding air. For small weapons, there are actually 2 flashes. The first is caused by the X-rays impacting the air immediately before it becomes optically opaque. And the second is as the fireball "burns through" the ionization-induced opacity. Largers weapons tend to "burn through" immediately with a resultant single long pulse of light. The spectrum of electromagnetic energy at a relatively large (compared to the weapon's size) distance is a complex mix of gammas resulting from prompt fission and fusion and gammas resulting from neutron capture and x-rays emitted by the weapon constituents and the surrounding air. At greater distances, the x-rays are attenuated and the spectrum is almost solely gamma. And since the probability of a neutron suffering an inelastic scatter with the resultant capture gamma emission rises with target Z, it is desirable to make this target from as heavy a material as possable. Thus the use of tungsten and other heavy metals that either do not appreciably activate or have short half lives. I will readily admit that my experience has been with a tiny slice of the weapons that we've used so I won't completely rule out unconventional designs. However, I will rule out theories that are not supported by physics. John -- John De Armond, WD4OQC | "The truly ignorant in our society are those people Radiation Systems, Inc. | who would throw away the parts of the Constitution Atlanta, Ga | they find inconvenient." -me Defend the 2nd {emory,uunet}!rsiatl!jgd| with the same fervor as you do the 1st.