NASA Scientific and Technical Aerospace Reports

Measurements of electromagnetic radiation pressure have been made on individual silica (SiO2) particles levitated in an
electrodynamic balance. These measurements were made by inserting single charged particles of known diameter in the 0.2to
6.82-micron range and irradiating them from above with laser radiation focused to beam widths of approximately 175- 400
microns at ambient pressures particle due to the radiation force is balanced by the electrostatic force indicated by the
compensating dc potential applied to the balance electrodes, providing a direct measure of the radiation force on the levitated
particle. Theoretical calculations of the radiation pressure with a least-squares fit to the measured data yield the radiation
pressure efficiencies of the particles, and comparisons with Mie scattering theory calculations provide the imaginary part of
the refractive index of SiO2 and the corresponding extinction and scattering efficiencies.
Author
Cosmic Dust; Electromagnetic Radiation; Pressure Measurement; Radiation Pressure; Silicon Dioxide; Electrodynamics
20040050280 Lockheed Martin Corp., Syracuse, NY, USA, Rensselaer Polytechnic Inst., Troy, NY, USA
Application of Monte Carlo Chord-Length Sampling Algorithms to Transport through a 2-D Binary Stochastic
Mixture
Donovan, T. J.; Danon, Y.; Mar. 2002; 26 pp.; In English
Report No.(s): DE2004-820707; LM-02K012; No Copyright; Avail: Department of Energy Information Bridge
Monte Carlo algorithms are developed to calculate the ensemble-average particle leakage through the boundaries of a 2-D
binary stochastic material. The mixture is specified within a rectangular area and consists of a fixed number of disks of
constant radius randomly embedded in a matrix material. The algorithms are extensions of the proposal of Zimmerman et al.,
using chord-length sampling to eliminate the need to explicitly model the geometry of the mixture. Two variations are
considered. The first algorithm uses Chord-Length Sampling (CLS) for both material regions. The second algorithm employs
Limited Chord Length Sampling (LCLS), only using chord-length sampling in the matrix material. Ensemble-average leakage
results are computed for a range of material interaction coefficients and compared against benchmark results for both accuracy
and efficiency. both algorithms are exact for purely absorbing materials and provide decreasing accuracy as scattering is
increased in the matrix material. The LCLS algorithm shows a better accuracy than the CLS algorithm for all cases while
maintaining an equivalent or better efficiency. Accuracy and efficiency problems with the CLS algorithm are due principally
to assumptions made in determining the chord-length distribution within the disks.
NTIS
Monte Carlo Method; Algorithms; Binary Mixtures
20040050293 Lawrence Livermore National Lab., Livermore, CA
ITER CS Model Coil and CS Insert Test Results
Martovetsky, N.; Michael, P.; Minervini, J.; Radovinsky, A.; Takayasu, M.; Sep. 07, 2000; 12 pp.; In English
Report No.(s): DE2004-15006127; UCRL-JC-140341; No Copyright; Avail: Department of Energy Information Bridge
The Inner and Outer modules of the Central Solenoid Model Coil (CSMC) were built by US and Japanese home teams
in collaboration with European and Russian teams to demonstrate the feasibility of a superconducting Central Solenoid for
ITER and other large tokamak reactors. The CSMC mass is about 120 t, OD is about 3.6 m and the stored energy is 640 MJ
at 46 kA and peak field of 13 T. Testing of the CSMC and the CS Insert took place at Japan Atomic Energy Research Institute
(JAERI) from mid March until mid August 2000. This paper presents the main results of the tests performed.
NTIS
Solenoids; Superconducting Magnets
20040050310 Fermi National Accelerator Lab., Batavia, IL, USA
CDF Silicon Vertex Detector for Run II
Rossin, R.; Jan. 2004; 14 pp.; In English
Report No.(s): DE2004-820607; FERMILAB-CONF-03/397-E; No Copyright; Avail: Department of Energy Information
Bridge
The 8 layer, 720k channel CDF Run 2 silicon detector is an essential part of the heavy flavor tagging and forward tracking
capabilities of the CDF experiment. A summary of the experience in commissioning and operating this double-sided detector
during the first 2 years of Run 2 is presented. The performances of the silicon in term of resolution, efficiency are also
described. The results of the studies of radiation damage and the expected operational limits are discussed. A short description
of the SVT, the Level 2 Silicon Vertex Trigger, one of the major upgrades related to the new silicon device is also presented.
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