52 Matching Results

Search Results

Results: 1 - 24 next
open access

SECONDARY ELECTRON EMISSION MEASUREMENTS FOR TIN COATING ON THE STAINLESS STEEL OF SNS ACCUMULATOR RING VACUUM CHAMBER.

Description: BNL is responsible for the design and construction of the US Spallation Neutron Source (SNS) accumulator ring. Titanium Nitride (TiN) coating on the stainless steel vacuum chamber of the SNS accumulator ring is needed to reduce the secondary electron yield (SEY) and the undesirable resonant multiplication of electrons. The total SEY of TiN coated stainless steel material has been measured after coating samples were exposed to air and after electron and ion bombardment. We report here about TiN … more
Date: July 5, 2004
Creator: HE,P. HSEUH,H. C. TODD,R. J. ET AL.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

RF TECHNIQUES FOR IMPROVED LUMINOSITY IN RHIC.

Description: The luminosity of the Relativistic Heavy Ion Collider has improved significantly [1] over the first three physics runs. A number of special rf techniques have been developed to facilitate higher luminosity. The techniques described herein include: an ultra low-noise rf source for the 197 MHz storage rf system, a frequency shift switch-on technique for transferring bunches from the acceleration to the storage system, synchronizing the rings during the energy ramp (including crossing the transiti… more
Date: July 5, 2004
Creator: BRENNAN,J. M. BLASKIEWICZ,J. BUTLER,J. DELONG,J. FISCHER,W. HAYES,T.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

A Low Noise RF Source for RHIC

Description: The Relativistic Heavy Ion Collider (RHIC) requires a low noise rf source to ensure that beam lifetime during a store is not limited by the rf system. The beam is particularly sensitive to noise from power line harmonics. Additionally, the rf source must be flexible enough to handle the frequency jump required for rebucketing (transferring bunches from the acceleration to the storage rf systems). This paper will describe the design of a Direct Digital Synthesizer (DDS) based system that provide… more
Date: July 5, 2004
Creator: Hayes, T.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

STOCHASTIC COOLING POWER REQUIREMENTS.

Description: A practical obstacle for stochastic cooling in high-energy colliders like RHIC is the large amount of power needed for the cooling system. Based on the coasting-beam Fokker-Planck (F-P) equation, we analytically derived the optimum cooling rate and cooling power for a beam of uniform distribution and a cooling system of linear gain function. The results indicate that the usual back-of-envelope formula over-estimated the cooling power by a factor of the mixing factor M. On the other hand, the sc… more
Date: July 5, 2004
Creator: Wei, J.; Blaskiewicz, M. & Brennan, M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

ACCELERATION OF POLARIZED BEAMS USING MULTIPLE STRONG PARTIAL SIBERIAN SNAKES.

Description: Acceleration of polarized protons in the energy range of 5 to 25 GeV is particularly difficult since depolarizing spin resonances are strong enough to cause significant depolarization but full Siberian snakes cause intolerably large orbit excursions. Using a 20-30% partial Siberian snake both imperfection and intrinsic resonances can be overcome. Such a strong partial Siberian snake was designed for the Brookhaven AGS using a dual pitch helical superconducting dipole. Multiple strong partial sn… more
Date: July 5, 2004
Creator: ROSER,T. AHRENS,L. BAI,M. ET AL.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

A METHOD TO MEASURE THE FOCUSING PROPERTIES (R-MATRIX) OF A MAGNET.

Description: In this paper we discuss, and study the feasibility of a method that may be used to measure the focusing properties of a magnet. This method may prove valuable when applied to ''non-conventional'' magnets that deviate from the usual dipole magnets or other multipole magnets (quadrupoles/sextupoles etc.) which are commonly used in a synchrotron or a beam line. In this category of ''non-conventional'' magnets, fall special magnets, which come under the name ''Snakes'', which are being used in syn… more
Date: July 5, 2004
Creator: TSOUPAS,N. THIEBERGER,P. BROWN,K. GASSNER,D. GLENN,W. AHRENS,L. ROSER,T. LEE,Y. Y. WEI,J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

BEAM SCRUBBING FOR RHIC POLARIZED PROTON RUN.

Description: One of the intensity limiting factor of RHIC polarized proton beam is the electron cloud induced pressure rise. A beam scrubbing study shows that with a reasonable period of time of running high intensity 112-bunch proton beam, the pressure rise can be reduced, allowing higher beam intensity.
Date: July 5, 2004
Creator: ZHANG,S. Y. FISCHER,W. HUANG,H. ROSER,T.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

STOCHASTIC COOLING STUDIES IN RHIC, II.

Description: Intra-beam scattering (IBS) is unavoidable for highly charged heavy ions and causes emittance growth during the store for collision physics. A longitudinal bunched beam stochastic cooling system will confine the bunch within the RF bucket increasing the useful luminosity. We describe a series of measurements in RHIC that have been used to verify our understanding of the relevant physics and the cooling system architecture that is being prototyped.
Date: July 5, 2004
Creator: BLASKIEWICZ,M. BRENNAN,J. M. WEI,J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

DIPOLE AND QUADRUPOLE SORTING FOR THE SNS RING.

Description: The Spallation Neutron Source (SNS) accumulator ring is a high intensity ring and must have low uncontrolled losses for hands on maintenance. To achieve these low losses one needs very tight tolerance. These tight tolerances have been achieved through shimming the magnets and sorting. Dipoles are solid core magnets and had very good field quality but magnet to magnet variation were sorted out according to ITF, since all the dipole are powered with one power supply. Typically, sorting is done to… more
Date: July 5, 2004
Creator: RAPARIA,D. FEDOTOV,A. LEE,Y. Y. ET AL.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

ELECTRON ACCELERATION FOR E-RHIC WITH THE NON-SCALING FFAG.

Description: A non-scaling FFAG lattice design to accelerate electrons from 3.2 to 10 GeV is described. This is one of possible solutions for the future electron-ion collider (eRHIC) at Relativistic Heavy Ion Collier (RHIC) at Brookhaven National Laboratory (BNL). The e-RHIC proposal requires acceleration of the low emittance electrons up to energy of 10 GeV. To reduce a high cost of the full energy super-conducting linear accelerator an alternative approach with the FFAG is considered. The report describes… more
Date: July 5, 2004
Creator: TRBOJEVIC,D. BALSKIEWICZ,M. COURANT,E. D. ET AL.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

1.5-GEV FFAG ACCELERATOR AS INJECTOR TO THE BNL-AGS.

Description: A 1.5-GeV Fixed-Field Alternating-Gradient (FFAG) proton Accelerator is being studied as a new injector to the Alternating-Gradient Synchrotron (AGS) of Brookhaven National Laboratory (BNL). The major benefit is that it would considerably shorten the overall AGS acceleration cycle, and, consequently, may yield to an improvement of beam stability, intensity and size. The AGS-FFAG will also facilitate the proposed upgrade of the AGS facility toward a 1-MW average proton beam power at the top ener… more
Date: July 5, 2004
Creator: Ruggiero, A. G.; Blaskiewicz, M.; Trbojevic, D.; Tsoupas, N. & Zhang, W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Analysis of Electron Cloud at Rhic.

Description: Pressure rises with high intense beams are among the main luminosity limitations at RHIC. Observations during the latest runs show beam induced electron multipacting as one of the causes for these pressure rises. Experimental studies are carried out at RHIC using devoted instrumentation to understand the mechanism leading to electron clouds. In the following, we report the experimental electron cloud data and the analyzed results using computer simulation codes.
Date: July 5, 2004
Creator: Iriso, U.; Blaskiewicz, M.; Cameron, P.; Drees, A.; Fischer, W. & Al., Et
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Transition Crossing for the BNL Super Neutrino Beam Facility.

Description: The super neutrino beam facility proposed at the Brookhaven National Laboratory requires proton beams to cross the transition energy in the AGS to reach 1 MW beam power at top energy. High intensity beams are accelerated at a fast repetition rate. Upon transition crossing, such high intensity bunches of large momentum spreads suffer from strong nonlinear chromatic effects and self-field effects. Using theoretical and experimental methods, we determine the impact of these effects and the effecti… more
Date: July 5, 2004
Creator: Wei, J. & Tsoupas, N.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

RHIC Pressure Rise.

Description: Beam induced pressure rise remains an intensity limit at RHIC for both heavy ion and polarized proton operations. The pressure rises at beam injection, transition, and rebucketing are discussed, where the beam rebucketing pressure rise is probably of most concern for upcoming runs. Counter measures and results of beam studies are presented.
Date: July 5, 2004
Creator: ZHANG,S. Y. ALESSI,J. BAI,M. BLASKIEWICZ,M. ET AL.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

TRANSVERSE OPTICS IMPROVEMENTS FOR RHIC RUN 4.

Description: The magnetic settings in RHIC are driven by an on-line model, and the quality of the resulting lattice functions depend on the correctness of the settings, and knowledge of the magnet transfer-functions. Here we first present the different inputs into the model, including dipole sextupole components, used to set tunes and chromaticities along the ramp. Based on an analysis of measured tunes along the FY03 polarized proton ramp, we present predictions for quadrupole transfer-function changes whi… more
Date: July 5, 2004
Creator: Van Zeijts, J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Results From the Commissioning of the Nsrl Beam Transfer Line at Bnl.

Description: The NASA SPACE RADIATION LABORATORY (NSRL) has been constructed and started operations at the Brookhaven National Laboratory in 2003. The NSRL facility will be used by NASA to perform radiation effect studies on materials and biological samples for the space program. The facility utilizes proton and heavy-ion beams of energies from 50 to 3000 MeVln which are accelerated by the AGS Booster synchrotron accelerator. To date, {sup 1}H, {sup 12}C, {sup 56}Fe, {sup 48}Ti, and {sup 197}Au ion beams of… more
Date: July 5, 2004
Creator: Tsoupas, N.; Bellavia, S.; Bonati, R. & Al., Et
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

AN ONLINE LONGITUDINAL VERTEX AND BUNCH SPECTRUM MONITOR FOR RHIC.

Description: The longitudinal bunch profile acquisition system at RHIC was recently upgraded to allow on-line measurements of the bunch spectrum, and collision vertex location and shape. The system allows monitoring the evolution of these properties along the ramp, at transition and rebucketing, and at store conditions. We describe some of the hardware and software changes, and show some applications of the system.
Date: July 5, 2004
Creator: VAN ZEIJTS,J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

MEASUREMENT OF MULTIPOLE STRENGTHS FROM RHIC BPM DATA.

Description: Recently resonance driving terms were successfully measured in the CERN SPS and the BNL RHIC from the Fourier spectrum of BPM data. Based on these measurements a new analysis has been derived to extract multipole strengths. In this paper we present experimental measurements of sextupolar and skew quadrupolar strengths carried out at RHIC. A non-destructive measurement using an AC dipole is also presented.
Date: July 5, 2004
Creator: TOMAS,R. BAI,M. FISCHER,W. ET AL.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

A PRACTICAL DEMONSTRATION OF THE CRFQ STORAGE RING.

Description: A collaboration between Brookhaven National Laboratory, the University of Naples, the University of Sannio, and the INFN-Section of Naples (Italy) was created for the purpose of developing a proof of principle of the Circular Radiofrequency Quadrupole (CRFQ). This is a new concept of particle storage and accelerator ring, basically a Linear Radio-Frequency Quadrupole completely bent on a circle. The advantages are expected to be equivalent to those of a Linear RFQ, namely higher beam intensity … more
Date: July 5, 2004
Creator: RUGGIERO,A. G. CAMPAJOLA,L. VACCARO,V. G. ET AL.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

RF Excitation of Linear and Curved Sections of the CRFQ Project

Description: The design criteria of the linear and first curved sectors of the Circular Radiofrequency Quadrupole (CRFQ) proof of principle are presented in this paper. Radiofrequency measurements on a cold model of the linear sector and comparisons with numerical simulations are presented too.
Date: July 5, 2004
Creator: Davino, D.; Campajola, L.; Masullo, M. R. & Ruggiero, A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

QUEST FOR A NEW WORKING POINT IN RHIC.

Description: The beam-beam interaction is a limiting factor in RHIC's performance, particularly in proton operation. Changing the working point is a strategy to alleviate the beam-beam effect and improve the performance of the machine. Experiments at injection energy and simulations have been performed for a set of working points to determine the best candidates.
Date: July 5, 2004
Creator: TOMAS,R. BAI,M. FISCHER,W. PTITSYN,V. SATOGATA,T. ROSER,T.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

RHIC OPERATION WITH LONGITUDINALLY POLARIZED PROTONS.

Description: Polarized proton beams have been accelerated, stored and collided at 100GeV per beam in the Relativistic Heavy Ion Collider (RHIC) with longitudinal polarization. The essential equipment includes four Siberian snakes, eight spin rotators and fast relative polarimeters in each of the two RHIC rings as well as local polarimeters at the STAR and PHENIX detectors. This paper summarizes the performance of RHIC as a polarized proton collider in the FY03 run with emphasis on polarization issues. Preli… more
Date: July 5, 2004
Creator: HUANG,H. BAI,M. BEEBE-WANG,J. ET AL.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

PRINCIPLE OF SKEW QUADRUPOLE MODULATION TO MEASURE BETATRON COUPLING.

Description: The measurement of the residual betatron coupling via skew quadrupole modulation is a new diagnostics technique that has been developed and tested at the Relativistic Heavy Ion Collider (RHIC) as a very promising method for the linear decoupling on the ramp. By modulating the strengths of different skew quadrupole families the two eigentunes are precisely measured with the phase lock loop system. The projections of the residual coupling coefficient onto the skew quadrupole coupling modulation d… more
Date: July 5, 2004
Creator: LUO. Y. PILAT,F. ROSER,T. ET AL.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

CONTINUOUS ABORT GAP CLEANING AT RHIC.

Description: Since the RHIC Au-Au run in the year 2001 the 200 MHz cavity system was used at storage and a 28 MHz system during injection and acceleration. The rebucketing procedure potentially causes a higher debunching rate of heavy ion beams in addition to amplifying debunching due to other mechanisms. At the end of a four hour store, debunched beam can easily account for more than 50% of the total beam intensity. This effect is even stronger with the achieved high intensities of the RHIC Au-Au run in 20… more
Date: July 5, 2004
Creator: DREES,A. FLILLER,R. III. FU,W. MICHNOFF,R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
Back to Top of Screen