GULF In their underground classroom Gail had available several types of apparatus to record and manipulate light and sound.
To keep the crew and the computers alive you have to shield them from both gamma rays and pions. As far as the crew is concerned both reaction products come under the heading of "deadly radiation.
Given an absorbing propellant or radiation shield of a specific density you can figure the thickness that will stop all the pions. This is the pion's "range" through that material.
In table the columns under the yellow bar show how many centimeters the "range" of the given stopping material is required to absorb MeV of pion energy.
The two sets of orange bars is because while the range is relatively constant for all high energies, the range becomes dramatically less at the point where the pion energy drops below MeV the "last MeV". But you only need 27 centimeters of water to absorb MeV from a 75 MeV pion. Since hydrogen, helium, and nitrogen have regrettably low densities the reaction chamber will have to operate at high pressure to get the density up to useful levels.
The Space Shuttle engines operated at a pressure of atmospheres, is a bit excessive. So of the gases nitrogen might be preferrable, even though you can get better specific impulse out of propellants with lower molecular weight. Range of charged pions from Antiproton Annihilation Propulsion Using more calculations that were not explained figure was produced.
The curve is the relative intensity of a charged pion at a given kinetic energy in MeV. The MeV pions are the most intense there are more of themthe average energy is MeV.
Mean Life is the lifespan not half-life of a pion at that energy in nanoseconds. The range of a pion at that energy can be measured on the RANGE scales below, traveling through vacuum, hydrogen H2 propellant at atm, nitrogen N2 propellant at atm, and tungsten radiation shielding.
Gamma Rays Sadly gamma rays cannot be used to propel the rocket well, actually there are a couple of strange designs that do use gammasall they do is kill anything living and destroy electronic equipment.
So you have to shield the crew and electronics with radiation shielding. This is one of the big drawbacks to antimatter rockets.
Gamma-rays would be useful if you were using antimatter as some sort of weapon instead of propulsion. A small number of "prompt" gamma-rays are produced directly from the annihilation reaction.
The prompt gammas have a whopping MeV, but they only contribute about 0. A much larger amount of "delayed" gamma-rays are produced by the neutral pions decaying 90 attoseconds after the antimatter reaction.
As mentioned abovethe antimatter reaction is basically spitting out charged pions and gamma rays. The pions can be absorbed by the propellant and their energy utilized. The gamma rays on the other hand are just an inconvenient blast of deadly radiation traveling in all directions. The only redeeming feature is gamma rays are not neutrons, so at least they don't infect the ship structure with neutron embrittlement and turn the ship radioactive with neutron activation.
Since gamma rays are rays, not particles, they have that pesky exponential attenuation with shielding. It is like Zemo's paradox of Achilles and the tortoisemaking the radiation shielding thicker reduces the amount of gamma rays penetrating but no matter how thick it becomes the gamma leakage never quite goes to zero.
Particle shielding on the other hand have a thickness where nothing penetrates. Gamma rays with energies higher than MeV have a "attenuation coefficient" of about 0. Since tungsten has a density of Table gives the attunation for various thickness of tungsten radiation shields.
This tells us that a 2 centimeter thick shield would absorb The main things that have to be shielded are the crew, the electronics, the cryogenic tankage, and the magnetic coils if this particular antimatter engine utilzes coils.
The radiation flux will be pretty bad. Well, actually the report says megawatts so obviously I made a mistake somewhere.roamer, Using Roger’s method, why not calculate the cost of energy storage systems for just 50% renewables to cover the much larger amounts of storage needed to meet demand during extended windless periods (which can occur at any time and at random) and low sunlight periods (which occur mostly in winter, due to snow, ice, fog, etc.), and to flatten out seasonal variations in solar output.
The Alternative Energy Source to Oil Essay - The Alternative Energy Source to Oil Introduction “Renewable Energy” is the term used to describe those energy flows that occur naturally and repeatedly in the environment, e.g.
from the sun, wind and the oceans, and from plants and the fall of water.
Paul Kingsnorth is a writer and poet living in Cumbria, England. He is the author of several books, including the poetry collection Kidland and his fictional debut The Wake, winner of the Gordon Burn Prize and the Bookseller Book of the Year Award.
Kingsnorth is the cofounder and director of the Dark Mountain Project, a network of writers, artists, and thinkers. Why the future doesn’t need us. Our most powerful 21st-century technologies – robotics, genetic engineering, and nanotech – are threatening to make humans an endangered species.
From the. Lojban language logo; Many science fiction novels have noted how difficult, illogical, unscientific, and inefficient the English language is (did you know that "ghoti" should be pronounced "fish?").It is certainly a burden for people to learn as a second language, and even more so to try and teach to an alien race.
Nikola Tesla's article The Problem of Increasing Human Energy which first appeared in the June Century Magazine. Written shortly after his return from Colorado, this piece contains a comprehensive description of Tesla's vision regarding man's technological future.