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1.06 μm 150 psec laser damage study of diamond turned, diamond turned/ polished and polished metal mirrors

Description: Using a well characterized 1.06 μm 150 ps glass laser pulse the damage characteristics for diamond turned, diamond turned/ polished, and polished copper and silver mirrors less than 5 cm diameter were studied. Although most samples were tested with a normal angle of incidence, some were tested at 45$sup 0$ with different linear polarization showing an increase in damage threshold for S polarization. Different damage mechanisms observed will be discussed. Laser damage is related to residual surface influences of the fabrication process. First attempts to polish diamond turned surfaces resulted in a significant decrease in laser damage threshold. The importance of including the heat of fusion in the one dimensional heat analysis of the theoretical damage threshold and how close the samples came to the theoretical damage threshold is discussed. (auth)
Date: July 24, 1975
Creator: Saito, T. T.; Milam, D.; Baker, P. & Murphy, G.
Partner: UNT Libraries Government Documents Department
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Eighteenth year progress report, July 1, 1974--June 31, 1975

Description: Progress is reported for studies on the effects of embryonic x irradiation at doses of 50 or 100 R on the lifespan and incidence of leukemia in adult mice and rats. The effects of three 100 R doses on the first day of gestation on cell death in the embryos were also studied. (CH)
Date: January 1, 1975
Partner: UNT Libraries Government Documents Department
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Radiation-enhanced diffusion in metals and alloys

Description: Some phenomena that involves diffusion during irradiation include fission-product redistribution in reactor fuels, defect clustering in CTR walls or fast-reactor cladding, smearing-out of gradients in ion-implanted semiconductors, and microstructure development in a HVEM. This paper is a review of the basics of radiation-enhanced diffusion (REM). The present status of REM today is somewhat the same as diffusion in the 1940's, and recommendations are made for further work. 105 references. (DLC)
Date: January 1, 1975
Creator: Lam, N. Q. & Rothman, S. J.
Partner: UNT Libraries Government Documents Department
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Damages to DNA that result in neoplastic transformation

Description: Some topics discussed are: correlation between carcinogens and mutagens; defective DNA repair in uv-damaged xeroderma pigmentosum cells; analysis of nucleotide damage to DNA following exposure to chemicals or radiations; photoreactivation in uv-irradiated Escherichia coli; tumor development in fish; excision repair as an aid in identifying damage; detection of excision repair; role of endonucleases in repair of uv damage; and alkylation products and tumors. (HLW)
Date: January 1, 1975
Creator: Setlow, R.B.
Partner: UNT Libraries Government Documents Department
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Replacement collision sequences in metals

Description: The concept of radiation-induced defects traveling large distances by focussed collision sequences (focusons) without thermal activation has important consequences in radiation effect studies. The focussed collision sequences are of two types: (1) ''Silsbee focussing'' or momentum focussing which can cause defect pairs to form large distances from the primary knock-on and (2) focussed replacement collisions also called ''dynamic crowdions'' where mass transport causes a large separation between the vacancy and its interstitial. Direct experimental evidence for focussed collision sequences is in short supply and conflicting. The sputtering patterns associated with close packed crystalline directions from the backscattering of charged particles seemed to substantiate long-range focussed collisions until it was pointed out that collision chains need not be long to yield such patterns. More recently, transmission sputtering has been used with conflicting results. Ecker et al. found no evidence for focusons greater than 17 atom distances whereas preliminary results of Siedman et al. suggest several hundred atom distances. Keil and co-workers found evidence for replacement collision sequences of 100 atom distances by stereo electron microscopy of interstitial agglomerates interjected by low energy heavy ion bombardment. Experiments by Kirk et al. and Becker and co-workers on ordered alloys, are only sensitive to dynamic crowdions. Kirk and co-workers result on the changes in magnetic properties of Ni$sub 3$Mn induced by thermal neutron bombardment strongly support long range focusons (greater than 30 atom distances) whereas Wollenberger found no evidence for focusons with 1 and 3 MeV electron irradiation. Theoretical treatments of Liebfried suggest a maximum length of 30 atom distances whereas Holmes' modified treatment suggests less than 10 atom distances. (10 fig, 23 references) (auth)
Date: October 1, 1975
Creator: Blewitt, T. H.; Kirk, M. A. & Scott, T. L.
Partner: UNT Libraries Government Documents Department
open access

Standard Practice for Dosimetry of Proton Beams for use in Radiation Effects Testing of Electronics

Description: Representatives of facilities that routinely deliver protons for radiation effect testing are collaborating to establish a set of standard best practices for proton dosimetry. These best practices will be submitted to the ASTM International for adoption.
Date: July 25, 2008
Creator: McMahan, Margaret A.; Blackmore, Ewart; Cascio, Ethan W.; Castaneda, Carlos; von Przewoski, Barbara & Eisen, Harvey
Partner: UNT Libraries Government Documents Department
open access

Neutron Soft Errors in Xilinx FPGAs at Lawrence Berkeley National Laboratory

Description: The LBNL 88-Inch Cyclotron offers broad-spectrum neutrons for single event effects testing. We discuss results from this beamline for neutron soft upsets in Xilinx Virtex-4 and -5 field-programmable-gate-array (FPGA) devices.
Date: July 25, 2008
Creator: George, Jeffrey S.; Koga, Rocky & McMahan, Margaret A.
Partner: UNT Libraries Government Documents Department
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