Ho dei dubbi sia un vero progetto (oltre al fatto che ha una risoluzione ignobile)

The basic structure of this design was based on a series of concentric nested spheres (each discussed in detail in the paragraphs below) Starting from the outside (listing by outside radius) these were:


Explosive lens system 65 cm
Pusher/neutron absorber shell 23 cm
Uranium tamper/reflector shell 11.5 cm
Plutonium pit 4.5 cm
Beryllium neutron initiator 1.0 cm

The Pit

The pit of these devices contained 6.2 kg of a delta-phase plutonium alloy. The mass was provided in a declassified memorandum written by Gen. Groves to the Sec. of War two days after the Trinity test. He describes the device and the results of the test and states that the explosion was created by "13 and a half pounds of plutonium".

The pit was a 9.0 cm sphere, solid except for an approximately 2.5 cm cavity in the center for the modulated neutron initiator. The solid design was a conservative one suggested by Robert Christy to minimize asymmetry and instability problems during implosion. The sphere had a 2.5 cm hole and plutonium plug to allow initiator insertion after assembly of the sphere.

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The plutonium was stabilized in the low density delta phase (density 15.9) by alloying it with 3% gallium (by molar content, 0.8% by weight), but was otherwise of high purity.

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The pit was formed in two hemispheres, probably by first casting a blank, followed by hot pressing in a nickel carbonyl atmosphere. Since plutonium is a chemically very reactive metal, as well as a significant health hazard, each half-sphere was electroplated with nickel (or silver, as has been reported for the Gadget core). This created a problem with the Gadget pit since hasty electroplating had left plating solution trapped under the nickel (or silver), resulting in blistering that ruined the fit. Careful grinding and layering with gold leaf restored the necessary smooth finish. However a thin gold gasket (about 0.1 mm thick) between the hemispheres was a necessary feature of the design in any case to prevent premature penetration of shock wave jets between the hemispheres that could have prematurely activated the initiator.

The Neutron Initiator

The beryllium initiator used was called the "Urchin" or "screwball" design. It was a sphere consisting of a hollow beryllium shell, with a solid beryllium pellet inside, the whole initiator weighing about 7 grams. The outer shell was 2 cm wide and 0.6 cm thick, the solid inner sphere was 0.8 cm wide. 15 parallel wedge-shaped grooves, each 2.09 mm deep, were cut into the inner surface of the shell. Like the pit, the shell was formed in two halves by hot pressing in a nickel carbonyl atmosphere. The surfaces of the shell and central sphere were coated with 0.1 mm of gold, and also a nickel layer deposited by the nickel carbonyl atmosphere. 50 curies polonium-210 (11 mg) was deposited on the grooves inside the shell and on the central sphere.

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The Reflector/Tamper

The pit was surrounded by a natural uranium tamper weighing 120 kg, with a diameter of 23 cm. The tamper formed a 7 cm thick layer around the pit

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The Pusher/Neutron Absorber Shell

Surrounding the tamper was an 11.5 cm thick aluminum sphere also weighing 120 kg.

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Surrounding the tamper was a layer containing boron. Since boron itself is a brittle non-metal that is difficult to fabricate, this was most likely in the form of a malleable boron/aluminum alloy called boral (the composition is typically 35-50% boron). It is possible that the entire aluminum sphere might have been boral with a relatively low boron content

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The High Explosive Lens System

The entire high explosive implosion system made a layer some 47 cm thick weighing at least 2500 kg. This system consisted of 32 explosive lenses; 20 of them hexagonal, and 12 pentagonal. The lenses fitted together in the same pattern as a soccer ball, forming a complete spherical explosive assembly that was 140 cm wide. Each lens had three pieces: two made of high velocity explosive, and one of low velocity explosive. The outermost piece of high velocity explosive had a conical cavity in its inner surface into which fitted an appropriately shaped piece of slow explosive. These mated pieces formed the actual lens that shaped a convex, expanding shock wave into a convex converging one. An inner piece of high velocity explosive lay next to the aluminum sphere to amplify the convergent shock. The lenses were made by precision casting, so explosives that could be melted were used. The main high explosive was Composition B, a mixture of 60% RDX - a very high velocity but unmeltable explosive, 39% TNT - a good explosive that is easy to melt, and 1% wax. The slower second explosive was Baratol, it is a mixture of TNT and barium nitrate of variable composition (TNT is typically 25-33% of the mixture) with 1% wax as a binder. The high density of barium nitrate gives baratol a density of at least 2.5.

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To achieve the most precise detonation synchronization possible, conventional detonators consisting of an electrically heated wire, and a sequence of primary and secondary explosives were not used. Instead newly invented exploding wire detonators were used. This detonator consists of a thin wire that is explosively vaporized by a surge of current generated by a powerful capacitor. The shock wave of the exploding wire initiates the secondary explosive of the detonator (PETN). The discharge of the capacitor, and the generation of initiating shock waves by the exploding wires can be synchronized to +/- 10 nanoseconds. A disadvantage of this system is that large batteries, a high voltage power supply, and a very powerful capacitor bank (known as the X-Unit, the system weighed 400 lb) was needed to explode all 32 detonators simultaneously. A cascade of spark gap switches was used to trigger the capacitor bank.

The whole explosive assembly was held together by a shell made of a strong aluminum alloy called dural (or duraluminum). A number of other shell designs had been tried and discarded. This shell design, designated model 1561, was made of an equatorial band bolted together from 5 segments of machined dural castings, with domed caps bolted to the top and bottom to make a complete sphere.

The final bomb design allowed "trap door" assembly. The entire bomb could be assembled ahead of time, except for the pit/initiator. To complete the bomb, one of the domed caps was removed, along with one of the explosive lenses. The initiator was inserted between the plutonium hemispheres, and the assembled pit was inserted in a 40 kg uranium cylinder that slid into the tamper to make the complete core. The explosive lens was replaced, its detonator wires attached, and the cap bolted back into place.

E se fosse vero, credo non sentiremo parlare di Fabbri per un pò!
Sai, credo che da dopo l'11 settembre sia illegale postare documentazione pericolosa come un vero progetto di bomba atomica, non vorremmo che uno alla Ahmadinejad se ne impossessasse!