Economics of polysilicon process: A view from Japan

The production process of solar grade silicon (SOG-Si) through trichlorosilane (TCS) was researched in a program sponsored by New Energy Development Organization (NEDO). The NEDO process consists of the following two steps: TCS production from by-product silicon tetrachloride (STC) and SOG-Si formation from TCS using a fluidized bed reactor. Based on the data obtained during the research program, the manufacturing cost of the NEDO process and other polysilicon manufacturing processes were compared. The manufacturing cost was calculated on the basis of 1000 tons/year production. The cost estimate showed that the cost of producing silicon by all of the new processes is less than the cost by the conventional Siemens process. Using a new process, the cost of producing semiconductor grade silicon was found to be virtually the same with any to the TCS, diclorosilane, and monosilane processes when by-products were recycled. The SOG-Si manufacturing processes using the fluidized bed reactor, which needs further development, shows a greater probablility of cost reduction than the filament processes

Test of QEDPS: A Monte Carlo for the hard photon distributions in e+ e- annihilation proecss

The validity of a photon shower generator QEDPS has been examined in detail. This is formulated based on the leading-logarithmic renormalization equation for the electron structure function and it provides a photon shower along the initial e+-. The main interest in the present work is to test the reliability of the generator to describe a process accompanying hard photons which are detected. For this purpose, by taking the HZ production as the basic reaction, the total cross section and some distributions of the hard photons are compared between two cases that these photons come from either those generated by QEDPS or the hard process e+e- -> H Z gamma gamma. The comparison performed for the single and the double hard photon has shown a satisfactory agreement which demonstrated that the model is self-consistent.Comment: 22 pages, 4 Postscript figures, LaTeX, uses epsf.te

A QED Shower Including the Next-to-leading Logarithm Correction in e+e- Annihilation

We develop an event generator, NLL-QEDPS, based on the QED shower including the next-to-leading logarithm correction in the e^+e^- annihilation. The shower model is the Monte Carlo technique to solve the renormalization group equation so that they can calculate contributions of alpha^m log^n(S/m_e^2) for any m and n systematically. Here alpha is the QED coupling, m_e is the mass of electron and S is the square of the total energy in the e^+e^- system. While the previous QEDPS is limited to the leading logarithm approximation which includes only contributions of (alpha log(S/m_e^2))^n, the model developed here contains terms of alpha(alpha log(S/m_e^2))^n, the the next-to-leading logarithm correction. The shower model is formulated for the initial radiation in the e^+e^- annihilation. The generator based on it gives us events with q^2, which is a virtual mass squared of the virtual photon and/or Z-boson, in accuracy of 0.04%, except for small q^2/S.Comment: 35 pages, 1 figure(eps-file

Theoretical study of the decay-out spin of superdeformed bands in the Dy and Hg regions

Decay of the superdeformed bands have been studied mainly concentrating upon the decay-out spin, which is sensitive to the tunneling probability between the super- and normal-deformed wells. Although the basic features are well understood by the calculations, it is difficult to precisely reproduce the decay-out spins in some cases. Comparison of the systematic calculations with experimental data reveals that values of the calculated decay-out spins scatter more broadly around the average value in both the $A \approx$ 150 and 190 regions, which reflects the variety of calculated tunneling probability in each band.Comment: 6 pages 4 figures (30 PS files). To appear in Proc. of NS2000 (Nuclear Structure 2000) conf., at MSU, 15-19 Aug., 200