Measurements and Modeling of Eddy Current Effects in BNL's AGS Booster. (open access)

Measurements and Modeling of Eddy Current Effects in BNL's AGS Booster.

Recent beam experiments at BNL's AGS Booster have enabled us to study in more detail the effects of eddy currents on the lattice structure and our control over the betatron tune. The Booster is capable of operating at ramp rates as high as 9 T/sec. At these ramp rates eddy currents in the vacuum chambers significantly alter the fields and gradients seen by the beam as it is accelerated. The Booster was designed with these effects in mind and to help control the field uniformity and linearity in the Booster Dipoles special vacuum chambers were designed with current windings to negate the affect of the induced eddy currents. In this report results from betatron tune measurements and eddy current simulations will be presented. We will then present results from modeling the accelerator using the results of the magnetic field simulations and compare these to the measurements.
Date: June 23, 2006
Creator: Brown, K. A.; Ahrens, L.; Gardner, C.; Glenn, J. W.; Harvey, M.; Meng, W. et al.
System: The UNT Digital Library
Lattices for High-Power Proton Beam Acceleration and Secondary Beam Collection and Cooling. (open access)

Lattices for High-Power Proton Beam Acceleration and Secondary Beam Collection and Cooling.

Rapid cycling synchrotrons are used to accelerate high-intensity proton beams to energies of tens of GeV for secondary beam production. After primary beam collision with a target, the secondary beam can be collected, cooled, accelerated or decelerated by ancillary synchrotrons for various applications. In this paper, we first present a lattice for the main synchrotron. This lattice has: (a) flexible momentum compaction to avoid transition and to facilitate RF gymnastics (b) long straight sections for low-loss injection, extraction, and high-efficiency collimation (c) dispersion-free straights to avoid longitudinal-transverse coupling, and (d) momentum cleaning at locations of large dispersion with missing dipoles. Then, we present a lattice for a cooler ring for the secondary beam. The momentum compaction across half of this ring is near zero, while for the other half it is normal. Thus, bad mixing is minimized while good mixing is maintained for stochastic beam cooling.
Date: June 23, 2006
Creator: Wang, S.; Wei, J.; Brown, K.; Gardner, C.; Lee, Y. Y.; Lowenstein, D. et al.
System: The UNT Digital Library
Acceleration of Polarized Protons in the AGS With Two Helical Partial Snakes. (open access)

Acceleration of Polarized Protons in the AGS With Two Helical Partial Snakes.

Acceleration of polarized protons in the energy range of 5 to 25 GeV is particularly difficult: the depolarizing resonances are strong enough to cause significant depolarization but full Siberian snakes cause intolerably large orbit excursions and are not feasible in the AGS since straight sections are too short. Recently, two helical partial snakes with double pitch design have been built and installed in the AGS. With careful setup of optics at injection and along the ramp, this combination can eliminate the intrinsic and imperfection depolarizing resonances encountered during acceleration. This paper presents the accelerator setup and preliminary results.
Date: June 26, 2006
Creator: Huang, H.; Ahrens, L. A.; Bai, M.; Bravar, A.; Brown, K.; Courant, E. D. et al.
System: The UNT Digital Library
How the Common Component Architecture Advances Compuational Science (open access)

How the Common Component Architecture Advances Compuational Science

Computational chemists are using Common Component Architecture (CCA) technology to increase the parallel scalability of their application ten-fold. Combustion researchers are publishing science faster because the CCA manages software complexity for them. Both the solver and meshing communities in SciDAC are converging on community interface standards as a direct response to the novel level of interoperability that CCA presents. Yet, there is much more to do before component technology becomes mainstream computational science. This paper highlights the impact that the CCA has made on scientific applications, conveys some lessons learned from five years of the SciDAC program, and previews where applications could go with the additional capabilities that the CCA has planned for SciDAC 2.
Date: June 19, 2006
Creator: Kumfert, G; Bernholdt, D; Epperly, T; Kohl, J; McInnes, L C; Parker, S et al.
System: The UNT Digital Library
6th US-Russian Pu Science Workshop Lawrence Livermore National Laboratory University of California, Livermore, California, July 14 and 15, 2006 (open access)

6th US-Russian Pu Science Workshop Lawrence Livermore National Laboratory University of California, Livermore, California, July 14 and 15, 2006

None
Date: June 20, 2006
Creator: Fluss, M.; Tobin, J.; Schwartz, A.; Petrovtsev, A. V.; Nadykto, B. A.; Timofeeva, L. F. et al.
System: The UNT Digital Library
Search for a pentaquark decaying to p K(S)0 (open access)

Search for a pentaquark decaying to p K(S)0

None
Date: June 1, 2006
Creator: Link, J. M.; Yager, P. M.; /UC, Davis; Anjos, J. C.; Bediaga, I.; Castromonte, C. et al.
System: The UNT Digital Library
Search for a heavy resonance decaying into a Z+jet final state in p anti-p collisions at s**(1/2) = 1.96-TeV using the D0 detector (open access)

Search for a heavy resonance decaying into a Z+jet final state in p anti-p collisions at s**(1/2) = 1.96-TeV using the D0 detector

We have searched for a heavy resonance decaying into a Z+jet final state in p{bar p} collisions at a center of mass energy of 1.96 TeV at the Fermilab Tevatron collider using the D0 detector. No indication for such a resonance was found in a data sample corresponding to an integrated luminosity of 370 pb{sup -1}. We set upper limits on the cross section times branching fraction for heavy resonance production at the 95% C.L. as a function of the resonance mass and width. The limits are interpreted within the framework of a specific model of excited quark production.
Date: June 1, 2006
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
System: The UNT Digital Library
Inflammation and Atrophy Precede Prostate Neoplasia in PhIP Induced Rat Model (open access)

Inflammation and Atrophy Precede Prostate Neoplasia in PhIP Induced Rat Model

2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine (PhIP) has been implicated as a major mutagenic heterocyclic amine in the human diet and is carcinogenic in the rat prostate. In order to validate PhIP induced rat prostate neoplasia as a model of human prostate cancer progression, we sought to study the earliest histologic and morphologic changes in the prostate and to follow the progressive changes over time. We fed 67 male Fischer F344 5 week old rats with PhIP (400 PPM) or control diets for 20 weeks, and then sacrificed animals for histomorphologic examination at age 25 weeks, 45 weeks, and 65 weeks. Animals treated with PhIP showed significantly more inflammation (P=.002 (25wk), >.001(45wk), .016(65wk)) and atrophy (P=.003(25wk), >.001(45wk), .006 (65wk)) in their prostate glands relative to controls. Prostatic intraepithelial neoplasia (PIN) occurred only in PhIP treated rats. PIN lesions arose in areas of glandular atrophy, most often in the ventral prostate. Atypical cells in areas of atrophy show loss of glutathione S-transferase pi immunostaining preceding development of PIN. None of the animals in this study developed invasive carcinomas differing from previous reports. Overall, these findings suggest that the pathogenesis of prostatic neoplasia in the PhIP treated rat prostate proceeds from inflammation to post-inflammatory proliferative atrophy to …
Date: June 1, 2006
Creator: Borowsky, A. D.; Dingley, K.; Ubick, E.; Turteltaub, K.; Cardiff, R. D. & DeVere-White, R.
System: The UNT Digital Library