Monday, May 03, 2010

Here's the Rest of the Story


Brian Wang pulls together some loose ends regarding the UCR creation of spin - polarised positronium, in the quest to create a Bose-Einstein Condensate (BEC). Apparently, the US military wants to use this path to create a gamma ray laser!
Plan of work.

The first annihilation laser will be made in the following steps:
1.Attain Bose-Einstein condensed (BEC) positronium.
2. Make a source capable of delivering 10^12 slow positron per second on a 1 mm target.
3.Develop a multiple trap for storing and releasing 10^13 positrons.
4. Observe stimulated annihilation.
5. Make 1J annihilation gamma ray laser pulses. [this one joule laser has to be scaled up about one million times to enable the nuclear fusion system described above]

A three year project to get through step 1 would proceed via the following tasks.
A. Year 1: Make a system for producing brightness enhanced 10 ns pulses of 10^7 5 keV positrons in a 10 micrometer diameter spot.
B. Year 1: Develop a method for making cavity structures in porous silica for containing BEC positronium.
C. Year 2: Make a BEC positronium target chamber with 4K cooling and optical access.
D. Year 3: Develop a laser system for detecting the BEC state via the disappearance of Doppler broadening.
E. Year 3: Characterize the positronium BEC by measuring the condensate fraction as a function of time, temperature and density.

Advantages of the proposed Gamma Ray Laser approach.

The advantages of photons with energies of several hundred keV, loosely termed “gamma-rays”, over optical energy photons for inflicting damage on a distant target or for igniting fusion reactions are:
* Gamma rays penetrate a target to a thickness of roughly 10 g/cm2 and so impart up to two orders of magnitude greater impulse for a given energy compared to visible or infrared photons, thus leading to the fissure of large objects.
* Gamma rays are not significantly deflected by the atmosphere or its fluctuations, although absorption by the air limits the range at sea level to approximately 100 m if no means if employed for making a transparent gamma-ray channel through the atmosphere.
* The small size of the gamma-ray laser would be advantageous for steering and portability.
* A small annihilation gamma-ray laser would be fuelled by stored antimatter (positrons), which would leave no trace of radioactivity, although a GJ device might need to be based on energy derived from fusion. _BrianWang

More on the military's program PDF

Power Point pdf from UCR researchers

Once you learn to play with these forms of matter at will, you are on the way to a lot of different destinations. Choosing the right destinations at that point will require a bit of wisdom.



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