Verification (mostly) for High Energy Density Radiation Transport: 5 Case Studies (open access)

Verification (mostly) for High Energy Density Radiation Transport: 5 Case Studies

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Date: August 25, 2006
Creator: Castor, J I
System: The UNT Digital Library
Test Results of a Nb3Sn Wind/React 'Stress-Managed' BlockDipole (open access)

Test Results of a Nb3Sn Wind/React 'Stress-Managed' BlockDipole

A second phase of a highfield dipole technology developmenthas been tested. A Nb3Sn block-coil model dipole was fabricated, usingmagnetic mirror geometry and wind/react coil technology. The primaryobjective of this phase was to make a first experimental test of thestress-management strategy pioneered at Texas A&M. In this strategy ahigh-strength support matrix is integrated with the windings to interceptLorentz stress from the inner winding so that it does not accumulate inthe outer winding. The magnet attained a field that was consistent withshort sample limit on the first quench; there was no training. Thedecoupling of Lorentz stress between inner and outer windings wasvalidated. In ramp rate studies the magnet exhibited a remarkablerobustness in rapid ramping operation. It reached 85 percent of shortsample(ss) current even while ramping 2-3 T/s. This robustness isattributed to the orientation of the Rutherford cables parallel to thefield in the windings, instead of the transverse orientation thatcharacterizes common dipole designs. Test results are presented and thenext development phase plans are discussed.
Date: August 25, 2006
Creator: McInturff, A.; Bish, P.; Blackburn, R.; Diaczenko, N.; Elliott,T.; Hafalia Jr., R. et al.
System: The UNT Digital Library
Updated Bounds on CP Asymmetries in B^0 to eta'K_S and B0 to pi^0K_S (open access)

Updated Bounds on CP Asymmetries in B^0 to eta'K_S and B0 to pi^0K_S

Previous analyses in which flavor SU(3) was used to constrain the coefficients of sin {Delta}mt and cos {Delta}mt in the time-dependent CP asymmetries of B{sup 0} {yields} {eta}'K{sub S} and B{sup 0} {yields} {pi}{sup 0} K{sub S} are updated using new rate measurements of B{sup 0} decays into {pi}{sup 0}{pi}{sup 0}, {pi}{sup 0},{eta}, {pi}{sup 0}{eta}', {eta}{eta}, {eta}{eta}', {eta}'{eta}' and K{sup +}K{sup -}.
Date: August 25, 2006
Creator: Gronau, Michael; Rosner, Jonathan L. & Zupan, Jure
System: The UNT Digital Library
Solid State Replacement of Rotating Mirror Cameras (open access)

Solid State Replacement of Rotating Mirror Cameras

Rotating mirror cameras have been the mainstay of mega-frame per second imaging for decades. There is still no electronic camera that can match a film based rotary mirror camera for the combination of frame count, speed, resolution and dynamic range. The rotary mirror cameras are predominantly used in the range of 0.1 to 100 micro-seconds per frame, for 25 to more than a hundred frames. Electron tube gated cameras dominate the sub microsecond regime but are frame count limited. Video cameras are pushing into the microsecond regime but are resolution limited by the high data rates. An all solid state architecture, dubbed ''In-situ Storage Image Sensor'' or ''ISIS'', by Prof. Goji Etoh, has made its first appearance into the market and its evaluation is discussed. Recent work at Lawrence Livermore National Laboratory has concentrated both on evaluation of the presently available technologies and exploring the capabilities of the ISIS architecture. It is clear though there is presently no single chip camera that can simultaneously match the rotary mirror cameras, the ISIS architecture has the potential to approach their performance.
Date: August 25, 2006
Creator: Frank, A M & Bartolick, J M
System: The UNT Digital Library
Fragmentation cross sections of 28Si at beam energies from 290AMeV to 1200A MeV (open access)

Fragmentation cross sections of 28Si at beam energies from 290AMeV to 1200A MeV

In planning for long-duration spaceflight, it will beimportant to accurately model the exposure of astronauts to heavy ions inthe Galactic Cosmic Rays (GCR). As part of an ongoing effort to improveheavy-ion transport codes that will be used in designing futurespacecraft and habitats, fragmentation cross sections of 28Si have beenmeasured using beams with extracted energies from 290A MeV to 1200A MeV,spanning most of the peak region of the energy distribution of siliconions in the GCR. Results were obtained for six elemental targets:hydrogen, carbon, aluminum, copper, tin, and lead. The charge-changingcross sections are found to be energy-independent within the experimentaluncertainties, except for those on the hydrogen target. Cross sectionsfor the heaviest fragments are found to decrease slightly with increasingenergy for lighter targets, but increase with energy for tin and leadtargets. The cross sections are compared to previous measurements atsimilar energies, and to predictions of the NUCFRG2 model used by NASA toevaluate radiation exposures in flight. For charge-changing crosssections, reasonable agreement is found between the present experimentand those of Webber, et al. and Flesch, et al., and NUCFRG2 agrees withthe data to within 3 percent in most cases. Fragment cross sections showless agreement between experiments, and there are substantial differencesbetween NUCFRG2 predictions andthe …
Date: August 25, 2006
Creator: Zeitlin, C.; Fukumura, A.; Guetersloh, S.B.; Heilbronn, L.H; Iwata, Y.; Miller, J. et al.
System: The UNT Digital Library