It's So Easy ? Mystery Cache
Hidden : 9/4/2014
Difficulty:
3 out of 5
Terrain:
3.5 out of 5

Size: Size: micro (micro)

Join now to view geocache location details. It's free!

Watch

How Geocaching Works
Looking for a different adventure?

Related Web Page

Please note Use of geocaching.com services is subject to the terms and conditions in our disclaimer.

Geocache Description:



Castle Bravo was the code name given to the first United States test of a dry fuel, hydrogen bomb, detonated on March 1, 1954, at Bikini Atoll, Marshall Islands, as the first test of Operation Castle. Castle Bravo was the most powerful nuclear device ever detonated by the United States (and just under one-third the energy of the Tsar Bomba), with a yield of 15 megatons of TNT. That yield, far exceeding the expected yield of 4 to 8 megatons (5 Mt predicted), combined with other factors, led to the most significant accidental radioactive contamination ever caused by the United States.

Fallout from the detonation—intended to be a secret test—fell on residents of Rongelap and Utirik atolls and spread around the world. The islanders were not evacuated until three days later and suffered radiation sickness. They were returned to the islands three years later but were removed again when their island was found to be unsafe. The crew of the Japanese fishing vessel Daigo Fukuryū Maru ("Lucky Dragon No. 5"), was also contaminated by fallout, killing one crew member. The blast created an international reaction about atmospheric thermonuclear testing.

The device was a very large cylinder weighing 23,500 pounds (10.7 t) and measuring 179.5 inches in length and 53.9 inches in diameter. It was mounted in a "shot cab" on an artificial island built on a reef off Namu Island, in the Bikini Atoll. A sizable array of diagnostic instruments was trained on it, including high-speed cameras trained through an arc of mirror towers around the shot cab.



The device detonated for the test was named "Shrimp". The Shrimp used lithium deuteride, which is solid at room temperature. Castle Bravo was the first test by the United States of a practical deliverable fusion bomb (hydrogen bomb).

Inside the cylindrical case was a smaller cylinder of lithium deuteride fusion fuel (the secondary) with a fission atomic bomb (the primary) at one end, the latter employed to create the conditions needed to start the fusion reaction. Running down the center of the secondary, was a cylindrical rod of plutonium (the sparkplug), which fissioned with compression and neutrons from the primary, and compressed the fusion material around it from the inside. Surrounding this assembly was a uranium tamper. The space between the tamper and the case formed a radiation channel to conduct X-rays from the primary to the secondary; the space is filled with plastic which turns to plasma from the x-rays, which in turn compress the secondary externally, increasing the density and temperature of the fusion fuel to the level needed to sustain a thermonuclear reaction.



It was practically identical to the "Runt" device later detonated in Castle Romeo, but used partially enriched lithium in the fusion fuel. Natural lithium is a mixture of lithium-6 and lithium-7 isotopes (with 7.5% of the former). The enriched lithium used in Bravo was approximately 40% lithium-6. The primary was a RACER IV tritium-boosted atomic bomb, specifically designed as a thermonuclear primary.

When Bravo was detonated, it formed a fireball almost four and a half miles across within a second. This fireball was visible on Kwajalein atoll over 250 miles away. The explosion left a crater 6,500 feet in diameter and 250 feet in depth. The mushroom cloud reached a height of 47,000 feet and a diameter of 7 miles in about a minute; it then reached a height of 130,000 feet and 62 miles in diameter in 9 minutes and was expanding at more than 220 mph. As a result of the blast, the cloud contaminated more than seven thousand square miles of the surrounding Pacific Ocean including some of the surrounding small islands like Rongerik, Rongelap and Utirik.



In terms of TNT tonnage equivalence, Castle Bravo was about 1,000 times more powerful than each of the atomic bombs which were dropped on Hiroshima and Nagasaki during World War II

The yield of 15 megatons was three times the yield of 5 Mt predicted by its designers. The cause of the higher yield was a theoretical error made by designers of the device at Los Alamos National Laboratory. They considered only the lithium-6 isotope in the lithium deuteride secondary to be reactive; the lithium-7 isotope, accounting for 60% of the lithium content, was assumed to be inert. It was expected that lithium-6 isotope would absorb a neutron from the fissioning plutonium and emit an alpha particle and tritium in the process, of which the latter would then fuse with the deuterium and increase the yield in a predicted manner. Lithium-6 indeed reacted in this manner.

It was assumed that the lithium-7 would absorb one neutron, producing lithium-8 which decays (via beryllium-8) to a pair of alpha particles on a timescale of seconds -- vastly longer than the timescale of nuclear detonation. However, when lithium-7 is bombarded with energetic neutrons, rather than simply absorbing a neutron, it captures the neutron and decays instantly into an alpha particle, a tritium nucleus, and another neutron. As a result, much more tritium was produced than expected, the extra tritium fusing with deuterium and producing an extra neutron. The extra neutron produced by fusion and the extra neutron released directly by lithium-7 decay produced a much larger neutron flux. The result was greatly increased fissioning of the uranium tamper and increased yield.

This resultant extra fuel (both lithium-6 and lithium-7) contributed greatly to the fusion reactions and neutron production and in this manner greatly increased the device's explosive output. The test used lithium with a high percentage of lithium-7 only because lithium-6 was then scarce and expensive; the later Castle Union test used almost pure lithium-6. Had sufficient lithium-6 been available, the usability of the common lithium-7 might not have been discovered.




10 Easy questions, it ain't rocket science.

A. The shrimp's primary was a RACER ? tritium-boosted atomic bomb.
B. Lithium-8 decays to ? alpha particles.
C. Castle Bravo was predicted to yield ? Mt.
D. When lithium-7 is bombarded with energetic neutrons, it captures the neutron and decays in ? seconds.
E. The mushroom cloud reached a diameter of 62 miles in ? minutes.
F. When lithium-7 is bombarded with energetic neutrons, it captures the neutron and decays into ? things.
G. Lithium-? isotope was mistakenly thought to be inert.
H. The shrimp was 40% lithium-?.
I. The fireball from Castle Bravo reached 4.5 miles across within ? second.
J. Lithium-7 did not absorb one neutron, producing lithium-? as expected.



Find the Detonation Code to solve for the final coordinates.


FTF ~ Corfman Clan ~ FTF

Additional Hints (No hints available.)



Attributes

No attributes available

Advertising with Us

Inventory

There are no Trackables in this cache.

View past Trackables

What are Trackable Items?