Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!samsung!zaphod.mps.ohio-state.edu!pacific.mps.ohio-state.edu!linac!att!cbnews!cbnews!military From: seeger@thedon.cis.ufl.edu (F. L. Charles Seeger III) Newsgroups: sci.military Subject: Re: The Neutron Bomb Message-ID: <1990Nov2.201046.27205@cbnews.att.com> Date: 2 Nov 90 20:10:46 GMT References: <43034@eerie.acsu.Buffalo.EDU> <1990Oct29.031806.9162@cbnews.att.com> <1990Oct30.052109.6742@cbnews.att.com> Sender: military@cbnews.att.com (William B. Thacker) Organization: UF CIS Dept Lines: 56 Approved: military@att.att.com 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