It separates the primary from the secondary and performs the same function as the previous reflector. There are about six neutron guns (seen here from Sandia National Laboratories) each poking through the outer edge of the reflector with one end in each section; Sony VAIO PCG-8152M Battery
all are clamped to the carriage and arranged more or less evenly around the casing's circumference. The neutron guns are tilted so the neutron emitting end of each gun end is pointed towards the central axis of the bomb. Neutrons from each neutron gun pass through and are focussed by the neutron focus lens towards the centre of primary in order to boost the initial fissioning of the plutonium. Sony VAIO PCG-31111M Battery
A "Polystyrene Polarizer/Plasma Source" is also shown (see below).
The first U.S. government document to mention the interstage was only recently released to the public promoting the 2004 initiation of the Reliable Replacement Warhead Program. Sony VAIO PCG-61111M Battery
A graphic includes blurbs describing the potential advantage of a RRW on a part by part level, with the interstage blurb saying a new design would replace "toxic, brittle material" and "expensive 'special' material... [which require] unique facilities". Sony VAIO PCG-51112M Battery
The "toxic, brittle material" is widely assumed to be beryllium, which fits that description and would also moderate the neutron flux from the primary. Some material to absorb and re-radiate the X-rays in a particular manner may also be used.
The "special material" is thought to be a substance called "FOGBANK",Sony VAIO PCG-51211M Battery
an unclassified codename, though it is often referred to as "THE fogbank" (or "A Fogbank") as if it were a subassembly instead of a material. Its composition is classified, though aerogel has been suggested as a possibility. Manufacture stopped for many years; however, the Life Extension Program required it to start up again – Sony VAIO PCG-51212M Battery
Y-12 currently being the sole producer (the "unique facility" referenced). Manufacture involves the moderately toxic and moderately volatile solvent called acetonitrile, which presents a hazard for workers (causing three evacuations in March 2006 alone).
A simplified summary of the above explanation would be: Sony VAIO PCG-41111M Battery
An implosion assembly type of fission bomb is exploded. This is the primary stage. If a small amount of deuterium/tritium gas is placed inside the primary's core, it will be compressed during the explosion and a nuclear fusion reaction will occur; Sony VAIO PCG-41111V Battery
the released neutrons from this fusion reaction will induce further fission in the plutonium-239 or uranium-235 used in the primary stage. The use of fusion fuel to enhance the efficiency of a fission reaction is called boosting. Without boosting, a large portion of the fissile material will remain unreacted; Sony VAIO PCG-61412V Battery
- the Little Boy and Fat Man bombs had anefficiency of only 1.4% and 17%, respectively, because they were unboosted.
Energy released in the primary stage is transferred to the secondary (or fusion) stage. The exact mechanism whereby this happens is unknown. This energy compresses the fusion fuel and sparkplug; Sony VAIO PCG-71112M Battery
the compressed sparkplug becomes critical and undergoes a fission chain reaction, further heating the compressed fusion fuel to a high enough temperature to induce fusion, and also supplying neutrons that react with lithium to create tritium for fusion. Generally, increasing the kinetic energy of gas molecules contained in a limited volume will increase both temperature and pressure (see gas laws). Sony VAIO PCG-81111V Battery
The fusion fuel of the secondary stage may be surrounded by depleted uranium or natural uranium, whose U-238 is not fissile and cannot sustain a chain reaction, but which is fissionable when bombarded by the high-energy neutrons released by fusion in the secondary stage. Sony VAIO PCG-81111V Battery
This process provides considerable energy yield (as much as half of the total yield in large devices), but is not considered a tertiary "stage". Tertiary stages are further fusion stages (see below), which have been only rarely used, and then only in the most powerful bombs ever made. Sony VAIO PCG-81212M Battery
Thermonuclear weapons may or may not use a boosted primary stage, use different types of fusion fuel, and may surround the fusion fuel with beryllium (or another neutron reflecting material) instead of depleted uranium to prevent further fission from occurring. Sony VAIO PCG-81212V Battery
The basic idea of the Teller–Ulam configuration is that each "stage" would undergo fission or fusion (or both) and release energy, much of which would be transferred to another stage to trigger it. How exactly the energy is "transported" from the primary to the secondary has been the subject of some disagreement in the open press, Sony VAIO PCG-51111M Battery
but is thought to be transmitted through the X-rays which are emitted from the fissioning primary. This energy is then used to compress thesecondary. The crucial detail of how the X-rays create the pressure is the main remaining disputed point in the unclassified press. There are five proposed theories: Sony VAIO VPCS13X9E/B battery
- Neutron pressure from the primary explosion. This was allegedly Ulam's first concept and was abandoned as unworkable.
- Blast wave from the primary explosion. This was allegedly Ulam's second concept and was abandoned as unworkable.
Radiation pressure exerted by the X-rays. Sony VAIO VPCS12V9E/B battery
- This was the first idea put forth by Howard Morland in the article in The Progressive.
- X-rays creating a plasma in the radiation case's filler (a polystyrene or "FOGBANK" plastic foam). This was a second idea put forward by Chuck Hansen and later by Howard Morland.
Tamper/Pusher ablation. Sony VAIO VPCS12V9E/B battery