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952 Matching Results
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952
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Notes on the Injection of EBIS Ions into Booster
N/A
Date:
June 1, 2006
Creator:
Gardner, C. J.
Object Type:
Report
System:
The UNT Digital Library
Correction Systems Upgrade for the Sns Ring.
In view of the changes in the design of the SNS ring from the original FODO lattice [l] to the 220m hybrid lattice [2] and finally 1.3GeV compatible 248m ring [3], complementary studies have been undertaken, in order to upgrade its correction packages. We review the evolution of the correction systems and present the accelerator physics studies for the adopted schemes and powering plan.
Date:
June 18, 2001
Creator:
Papaphilippou, Y.; GARDNER, C. J.; Lee, Y. Y. & Wei, J.
Object Type:
Article
System:
The UNT Digital Library
Oral History Interview with Robert W. Wilson, June 6, 2001
Access:
Use of this item is restricted to the UNT Community
Interview with airline pilot and Army Air Forces veteran Robert W. Wilson. The interview includes Wilson's personal experiences about being B-25 pilot in the Pacific Theater during World War II, basic training, college preparatory courses, flight training, and various missions. Wilson talks about his pre-war job experiences, flying conditions over the Owen Stanley Mountains, Operation OBOE, leave time in Sydney, Australia, the move to Palawan, Philippines, missions to French Indo-China, attitudes and feelings towards the deaths of comrades, and postwar adjustments. The interview includes an appendix with supplementary documents.
Date:
June 6, 2001
Creator:
Marcello, Ronald E. & Wilson, Robert W.
Object Type:
Book
System:
The UNT Digital Library
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.
Object Type:
Article
System:
The UNT Digital Library
The Rapid Cycling Medical Synchrotron RCMS.
Thirteen hadron beam therapy facilities began operation between 1990 and 2001 - 5 in Europe, 4 in North America, 3 in Japan, and 1 in South Africa [l]. Ten of them irradiate tumors with protons, 2 with Carbon- 12 ions, and 1 with both protons and Carbon-12. The facility with the highest patient throughput - a total of 6 174 patients in 11 years and as many as 150 patient treatments per day -is the Loma Linda University Medical Center, which uses a weak focusing slow cycling synchrotron to accelerate beam for delivery to passive scattering nozzles at the end of rotatable gantries [2, 3,4]. The Rapid Cycling Medical Synchrotron (RCMS) is a second generation synchrotron that, by contrast with the Loma Linda synchrotron, is strong focusing and rapid cycling, with a repetition rate of 30 Hz. Primary parameters for the RCMS are listed in Table 1.
Date:
June 2, 2002
Creator:
Peggs, S.; Barton, D.; Beebe-Wang, J.; Cardona, J.; Brennan, M.; Fischer, W. et al.
Object Type:
Article
System:
The UNT Digital Library
FODO/Doublet Lattice for the SNS Accumulator Ring.
Requirements of minimum beam loss for hand-on maintenance and flexibility for future operations are essential for the lattice design of the Spallation Neutron Source (SNS) accumulator ring. In this paper, we present a hybrid lattice that consists of FODO arcs and doublet straights, emphasizing injection and collimation optimization and flexibility, split tunes for coupling control, sextupole families for chromaticity control, and compatibility to future upgrades.
Date:
June 30, 2000
Creator:
Wei, J.; Gardner, C.; Lee, Y. Y. & Tsoupas, N.
Object Type:
Article
System:
The UNT Digital Library
Setup and Performance of the Rhic Injector Accelerators for the 2007 Run With Gold Ions
Gold ions for the 2007 run of the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) are accelerated in the Tandem, Booster and AGS prior to injection into RHIC. The setup and performance of this chain of accelerators is reviewed with a focus on improvements in the quality of beam delivered to RHIC. In particular, more uniform stripping foils between Booster and AGS7 and a new bunch merging scheme in AGS have provided beam bunches with reduced longitudinal emittance for RHIC.
Date:
June 25, 2007
Creator:
Gardner, C.; Ahrens, L.; Alessi, J.; Benjamin, J.; Blaskiewicz, M. & Al., Et
Object Type:
Article
System:
The UNT Digital Library
Uniform Beam Distributions at the Target of the NSRL Beam Transfer Line
Uniform irradiation of biological or material samples with charged particle beams is desired by experimenters because it reduces radiation dose errors. In this paper we present results of uniform beams produced in the NASA SPACE RADIATION LABORATORY (NSRL) at the Brookhaven National Laboratory (BNL) by a method which was developed theoretically and was proven experimentally at BNL. A similar method which requires collimation of the beam, and also lacks the flexibility of the present method to produce beam various beam sizes at the target, was patented in the year 1988. The present method of producing uniform beam distributions on a plane transverse to the direction of the beam, is based on purely magnetic focusing of the beam and requires no collimation of the beam or any other type of beam interaction with materials. It can also generate uniform beam distributions of various sizes. The method is favorably compared with alternative methods of producing uniform beam distributions and can be applied to the whole energy spectrum of the charged particle beams that are delivered by the BNL Booster synchrotron.
Date:
June 25, 2007
Creator:
Tsoupas, N.; Ahrens, L.; Brown, K. Chiang, I-Hung, Gardner, C. J.; MacKay, W. W.; Pile, P. & Rusek, A.
Object Type:
Article
System:
The UNT Digital Library
Overcoming Depolarizing Resonances in the AGS With Two Helical Partial Snakes
Dual partial snake scheme has provided polarized proton beams with 1.5 x 10{sup 11} intensity and 65% polarization for the Relativistic Heavy Ion Collider (RHIC) spin program. To overcome the residual polarization loss due to horizontal resonances in the Brookhaven Alternating Gradient Synchrotron (AGS), a new string of quadrupoles have been added. The horizontal tune can then be set in the spin tune gap generated by the two partial snakes, such that horizontal resonances can also be avoided. This paper presents the accelerator setup and preliminary results.
Date:
June 25, 2007
Creator:
Huang, H.; Ahrens, L.; Bai, M.; Brown, K. A.; Gardner, C. J.; Glenn, J. W. et al.
Object Type:
Article
System:
The UNT Digital Library
Setup and performance of RHIC for the 2008 run with deuteron-gold collisions.
This year (2008) deuterons and gold ions were collided in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) for the first time since 2003. The setup and performance of the collider for the 2008 run is reviewed with a focus on improvements that have led to an order of magnitude increase in luminosity over that achieved in the 2003 run.
Date:
June 23, 2008
Creator:
Gardner,C.; Abreu, N.P.; Ahren, L.; Alessi, J.; Bai, M. & al., et
Object Type:
Article
System:
The UNT Digital Library
STATUS AND RECENT PERFORMANCE OF THE ACCELERATORS THAT SERVE AS GOLD INJECTOR FOR RHIC.
The recent successful commissioning and operation [1] of the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) requires the injection of gold ions of specified energy and intensity with longitudinal and transverse emittances small enough to meet the luminosity requirements of the collider. Ion beams with the desired characteristics are provided by a series of three accelerators, the Tandem, Booster and AGS. The current status and recent performance of these accelerators are reviewed in this paper.
Date:
June 18, 2001
Creator:
Ahrens, L.; Alessi, J.; Van Asselt, W.; Benjamin, J.; Blaskiewicz, M.; Brennan, J. M. et al.
Object Type:
Article
System:
The UNT Digital Library
Structural properties of the geometrically frustrated pyrochlore Tb2Ti2O7
Although materials that exhibit nearest-neighbor-only antiferromagnetic interactions and geometrical frustration theoretically should not magnetically order in the absence of disorder, few such systems have been observed experimentally. One such system appears to be the pyrochlore Tb{sub 2}Ti{sub 2}O{sub 7}. However, previous structural studies indicated that Tb{sub 2}Ti{sub 2}O{sub 7} is an imperfect pyrochlore. To clarify the situation, we performed neutron powder diffraction (NPD) and x-ray absorption fine structure (XAFS) measurements on samples that were prepared identically to those that show no magnetic order. The NPD measurements show that the long-range structure of Tb{sub 2}Ti{sub 2}O{sub 7} is well ordered with no structural transitions between 4.5 and 600 K. In particular, mean-squared displacements (u{sup 2}'s) for each site follow a Debye model with no offsets. No evidence for Tb/Ti site interchange was observed within an upper limit of 2%. Likewise, no excess or deficiency in the oxygen stoichiometry was observed, within an upper limit of 2% of the nominal pyrochlore value. Tb L{sub III} and Ti K-edge XAFS measurements from 20-300 K similarly indicate a well-ordered local structure. Other aspects of the structure are considered. We conclude that Tb{sub 2}Ti{sub 2}O{sub 7} has, within experimental error, an ideal, disorder-free pyrochlore lattice, …
Date:
June 14, 2004
Creator:
Han, Sang-Wook; Gardner, Jason S. & Booth, Corwin H.
Object Type:
Article
System:
The UNT Digital Library
Fabrication of Cryogenic Manganite Bolometers to Measure the Total Energy at the LCLS Free Electron X-ray Laser
We are developing cryogenic bolometers to measure the total energy of the Linac Coherent Light Source (LCLS) free electron X-ray laser that is currently being built at the Stanford Linear Accelerator Center. LCLS will produce ultrashort {approx}200 fs X-ray laser pulses with {approx}10{sup 13} photons at 0.8 keV up to {approx}10{sup 12} photons at 8 keV per pulse at a repeat interval as short as 8 ms, and will be accompanied by a halo of spontaneous undulator radiation. Our bolometer consists of a 375 {micro}m thick Si absorber and a Nd{sub 0.67}Sr{sub 0.33}MnO{sub 3} sensor operated at its metal-insulator transition. It will measure the total energy of each pulse with a precision of <1%, and is designed to meet the conflicting requirements of radiation hardness, sensitivity, linearity over a dynamic range of three orders of magnitude, and readout speed compatible with the LCLS pulse rate. Here we discuss bolometer design and fabrication, and the photoresponse of prototype devices to pulsed optical lasers.
Date:
June 14, 2008
Creator:
Drury, O B; Yong, G J; Kolagani, R M; Liang, Y; Gardner, C; Ables, E et al.
Object Type:
Article
System:
The UNT Digital Library
AGS polarized proton operation in run 8.
Dual partial snake scheme has been used for the Brookhaven AGS (Alternating Gradient Synchrotron) polarized proton operation for several years. It has provided polarized proton beams with 1.5 x 10{sup 11} intensity and 65% polarization for RHIC spin program. There is still residual polarization loss. Several schemes such as putting horizontal tune into the spin tune gap, and injection-on-the-fly were tested in the AGS to mitigate the loss. This paper presents the experiment results and analysis.
Date:
June 23, 2008
Creator:
Huang, H.; Ahrens, L.; Bai, M.; Brown, K. A.; Gardner, C.; Glenn, J. W. et al.
Object Type:
Article
System:
The UNT Digital Library
Injection Choice for Spallation Neutron Source Ring.
Injection is key in the low-loss design of high-intensity proton facilities like the Spallation Neutron Source (SNS). During the design of both the accumulator and the rapid-cycling-synchrotron version of the SNS, extensive comparison has been made to select injection scenarios that satisfy SNS's low-loss design criteria. This paper presents issues and considerations pertaining to the final choice of the SNS injection systems.
Date:
June 18, 2001
Creator:
Wei, J.; Beebe-Wang, J.; Blaskiewicz, M.; Brodowski, J.; Fedotov, A.; Gardner, C. et al.
Object Type:
Article
System:
The UNT Digital Library
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.
Object Type:
Article
System:
The UNT Digital Library
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.
Object Type:
Article
System:
The UNT Digital Library
Low Loss Rapid Cycling Synchrotron Design for the Spallation Neutron Source.
None
Date:
June 30, 2000
Creator:
Wei, J.; Beebe-Wang, J.; Blaskiewicz, M.; Brennan, M.; Cameron, P.; Catalan-Lasheras, N. et al.
Object Type:
Article
System:
The UNT Digital Library
SNS Ring Study at the AGS Booster
During the g-2 run at the BNL AGS in early 2000, a 200 MeV storage-ring-like magnetic cycle has been set-up and tuned at the Booster in preparing for the Spallation Neutron Source (SNS) accumulator ring study. In this article, we report the progress of the machine set-up, tuning, some preliminary studies, and the future plan.
Date:
June 30, 2000
Creator:
Zhang, S. Y.; Ahrens, L.; Beebe-Wang, J.; Blaskiewicz, M.; Fedotov, A.; Gardner, C. et al.
Object Type:
Article
System:
The UNT Digital Library
WASP News, Volume 40, Number 1, June, 2002
Newsletter of the former World War II Women Airforce Service Pilots including news, events, stories about the group's history, and other information of interest to the members.
Date:
June 2002
Creator:
Women Airforce Service Pilots (U.S.)
Object Type:
Journal/Magazine/Newsletter
System:
The Portal to Texas History
TIME-RESOLVED 1-10 keV CRYSTAL SPECTROMETER FOR THE Z MACHINE AT SANDIA NATIONAL LABORATORIES
We have designed, fabricated, calibrated, and fielded a fast, time-resolved 1-10 keV crystal spectrometer to observe the evolution of wire pinch spectra at the Z machine at Sandia National Laboratories. The instrument has two convex cylindrical crystals (PET and KAP). Both crystals Bragg reflect x-rays into an array of ten silicon diodes, providing continuous spectral coverage in twenty channels from 1.0 to 10 keV. The spectral response of the instrument has been calibrated from 1.0 to 6.3 keV at beamline X8A at the National Synchrotron Light Source. The time response of the 1-mm2 silicon detectors was measured with the Pulsed X-ray Source at Bechtel Nevada's Los Alamos Operations, where 2-nanosecond full-width half-maximum (FWHM) waveforms with 700-picosecond rise times typically were observed. The spectrometer has been fielded recently on several experimental runs at the Z Machine. In this paper, we present the time-resolved spectra resulting from the implosions of double-nested tungsten wire arrays onto 5-mm diameter foam cylinders. We also show the results obtained for a double-nested stainless steel wire array with no target cylinder. The spectrometer was located at the end of a 7.1-meter beamline on line-of sight (LOS)21/22, at an angle 12{sup o} above the equatorial plane, and was …
Date:
June 1, 2003
Creator:
Morgan, D. V.; Gardner, S.; Liljestrand, R.; Madlener, M.; Slavin, S. & Wu, M.
Object Type:
Article
System:
The UNT Digital Library
Pre-treating Seed to Enhance Germination of Desert Shrubs
Creosotebush [Larrea tridentata (D.C.) Cav.] and white bursage [Ambrosia dumosa (A. Gray) W.W. Payne] seeds were subjected to pre-treatments of rinsing and soaking in water and thiourea to enhance germination in laboratory experiments. The effects of darkness, temperature, seed source, and soil moisture were also evaluated in the laboratory. The best pre-treatment from the laboratory experiments, rinsing with water for 36 hours followed by drying, was field-tested at Fort Irwin, California. Two sites and two seeding dates (early March and mid April) were determined for each site. Five mulch treatments (no mulch, straw, gravel, chemical stabilizer, and plastic) were evaluated in combination with the seed pre-treatments. Field emergence was greatly enhanced with the seed pre-treatment for white bursage during the March (18-42% increase in germination) and April seedings (16-23% increase in germination). Creosotebush showed poor germination during March (2-5%) when soil temperatures averaged 15 C, but germination increased during the April trials (6-43%) when soil temperatures averaged 23 C. The seed pre-treatment during the April trials increased germination from 16-23%. The plastic mulch treatment increased germination dramatically during both the March and April trials. The plastic mulch increased soil temperatures (8-10 C)and maintained high humidity during germination. Both the chemical …
Date:
June 1, 2002
Creator:
Ostler, W. K.; Anderson, D. C. & Hansen, D. J.
Object Type:
Article
System:
The UNT Digital Library
Injection and Acceleration of Au31+ in the BNL AGS.
Injection and acceleration of ions in a lower charge state reduces space charge effects, and, if further elcctron stripping is needed, may allow elimination of a stripping stage and the associated beam losses. The former is of interest to the accelerators in the GSI FAIR complex, the latter for BNL RHIC collider operation at energies lower than the current injection energy. Lower charge state ions, however, have a higher likelihood of electron stripping which can lead to dynamic pressures rises and subsequent beam losses. We report on experiments in the AGS where Au{sup 31+} ions were injected and accelerated instead of the normally used Au{sup 77+} ions. Beam intensities and the average pressure in the AGS ring are recorded, and compared with calculations for dynamic pressures and beam losses. The experimental results will be used to benchmark the StrahlSim dynamic vacuum code and will be incorporated in the GSI FAIR SIS100 design.
Date:
June 23, 2008
Creator:
Fischer, W.; Ahrens, L.; Brown, K.; Gardner, C.; Glenn, W.; Huang, H. et al.
Object Type:
Article
System:
The UNT Digital Library
Robust linear coupling correction with N-turn maps
N/A
Date:
June 1, 2003
Creator:
Fischer, W.
Object Type:
Report
System:
The UNT Digital Library