In the Feb, 2001 issue of R&D magazine, there is a very interesting article on the laser optics fabrication and problems associated with the LLNL National Ignition Facilities (NIF) 192 laser system.
This optics issue was a key complaint made by the GAO in the report, talked about early in this forum.
It seems that the whole business involved with the petawatt laser program is untested and based on ideal optics and materials yet to be successfully fabricated in the sizes needed.
This is a must read article for Inertial confinement fusion buffs who are part of the "go laser" crowd. It should be followed by any real fusion person or concerned taxpayer.
It seems the system will require about 7500 giant laser glass slabs and huge single crystals of potassium dihydrogen phoshate of un-paralleled purity and optical quality.
One single blimish or dust spot will destroy the optical element instantly. It is estimated that even with all items, flawlessly prepared and aligned, every 50-100 shots will require replacement of many of the main optical elements!!! This is exactly why the huge terawatt "NIKE" laser at NRL was shut down!! Estimated damage per shot was in the $50,000 dollar class when amortized over 200 shots and according to a personal friend who works there, it was always down for some major component failure.
In addition there are to be 15,000 small optical components in the system which must also be flawless.
GAO investigators pointed out that the the NIF folks were grossly underestimating the development and long term operating costs of the finished laser system.
The huge single crytals are custom grown over 72 days and are in the 326 kilogram catagory! The 7500 special glass slabs needed are estimated to weigh in at about 135,000 kilograms!
The monster KDP crystals are needed to make the IR triplers to convert the IR laser pulse output to UV (3 omega optics).
R&D magazine makes it sound like a wonderful challenge, while the GAO sounded like it was to be a money sink of monsterous proportions based on overrun costs extant 1 year ago!
Oh Well. A billion here, a billion there and pretty soon we're talking real money.
I highly recommend this article for electroptical megalomaniacs with visions and perhaps delusions of grandure.
Richard Hull
Created on Thursday, March 01, 2001 5:50 PM EDT by Richard Hull