Absolute Measurement of the Polarization of High Energy Proton Beams at RHIC (open access)

Absolute Measurement of the Polarization of High Energy Proton Beams at RHIC

The spin physics program at the Relativistic Heavy Ion Collider (RHIC) requires knowledge of the beam polarization to better than 5%. Such a goal is made the more difficult by the lack of knowledge of the analyzing power of high energy nuclear physics processes. To overcome this, a polarized hydrogen jet target was constructed and installed at one intersection region in RHIC where it intersects both beams and utilizes the precise knowledge of the jet atomic hydrogen beam polarization to measure the analyzing power in proton-proton elastic scattering in the Nuclear Coulomb Interference (CNI) region at the prescribed RHIC proton beam energy. The reverse reaction is used to assess the absolute beam polarization. Simultaneous measurements taken with fast high statistics polarimeters that measure the p-Carbon elastic scattering process also in the CNI region use the jet results to calibrate the latter.
Date: June 25, 2007
Creator: Makdisi, Y.; Bravar, A. Bunce, G. Gill, R.; Huang, H. & AL., ET
Object Type: Article
System: The UNT Digital Library
Accelerating Polarized Protons to 250 GEV (open access)

Accelerating Polarized Protons to 250 GEV

The Relativistic Heavy Ion Collider (RHIC) as the first high energy polarized proton collider was designed t o provide polarized proton collisions a t a maximum beam energy of 250 GeV. I t has been providing collisions a t a beam energy of 100 Gel' since 2001. Equipped with two full Siberian snakes in each ring, polarization is preserved during the acceleration from injection to 100 GeV with careful control of the betatron tunes and the vertical orbit distortions. However, the intrinsic spin resonances beyond 100 GeV are about a factor of two stronger than those below 100 GeV? making it important t o examine the impact of these strong intrinsic spin resonances on polarization survival and the tolerance for vertical orbit distortions. Polarized protons were accelerated t o the record energy of 250 GeV in RHIC with a polarization of 46% measured a t top energy in 2006. The polarization measurement as a function of beam energy also shows some polarization loss around 136 GeV, the first strong intrinsic resonance above 100 GeV. This paper presents the results and discusses the sensitivity of the polarization survival t o orbit distortions.
Date: June 25, 2007
Creator: Bai, M.; Ahrens, L.; Alekseev, I. G.; Alessi, J.; Beebe-Wang, J. & AL., ET
Object Type: Article
System: The UNT Digital Library
Acceleration of Electrons With the Racetrack Non-Scaling Ffag for E-Rhic (open access)

Acceleration of Electrons With the Racetrack Non-Scaling Ffag for E-Rhic

The future relativistic electron hadron collider: e-RHIC requires acceleration of electrons to 10 GeV. In the case that the super conducting linac is selected for acceleration, an energy recovery scheme is required. We propose to study a possibility of using the non-scaling Fixed-Field Gradient-Accelerator (NS-FFAG) for different energies. The beam will be accelerated by the superconducting linac at the top of the sine function, brought back to the front of the linac by the non-scaling FFAG and repeating this few times until the total energy of 20 GeV is reached. After collisions the beam is brought back by the non-scaling FFAG and decelerated (on the lower RF phase) in the same sequence but in the reverse order. Conventional and non-conventional beam dynamic issues will be discussed, like the transit time matching effect and the time of flight adjustments.
Date: June 25, 2007
Creator: Trbojevic, D.; Blaskiewicz, M.; Litvinenko, V.; Ptitsyn, V. & Roser, T.
Object Type: Article
System: The UNT Digital Library
Analysis and Simulation of Main Magnet Transmission Line Effect (open access)

Analysis and Simulation of Main Magnet Transmission Line Effect

A main magnet chain forms a pair of transmission lines. Pulse-reflection-caused voltage and current differentiation throughout the magnet chain can have adverse effect on main magnet field quality. This effect is associated with magnet system configuration, coupling efficiency, and parasitic parameters. A better understanding of this phenomenon will help us in new design and existing system upgrade. In this paper, we exam the transmission line effect due to different input functions as well as configuration, coupling, and other parameters.
Date: June 25, 2007
Creator: Zhang, W.; Marneris, I. & Sandberg, J.
Object Type: Article
System: The UNT Digital Library
Beam-Based Sextupole Polarity Verification in the RHIC (open access)

Beam-Based Sextupole Polarity Verification in the RHIC

This article presents a beam-based method to check RHIC arc sextupole polarities using local horizontal orbit three-bumps at injection energy. We use 11 bumps in each arc, each covering two SFs (focusing sextupoles) and one SD (defocusing sextupole). If there are no wrong sextupole polarities, the tune shifts from bump to bump and the tune shift patterns from arc to arc should be similar. Wrong sextupole polarities can be easily identified from mismatched signs or amplitudes of tune shifts from bump to bump and/or from arc to arc. Tune shifts in both planes during this study were tracked with a high-resolution base-band tunemeter (BBQ) system. This method was successfully used to the sextupole polarity check in RHIC Blue and Yellow rings in the RHIC 2006 and 2007 runs.
Date: June 25, 2007
Creator: Luo, Y.; Satogata, T.; Cameron, P.; Dellapenna, A. & Trbojevic, D.
Object Type: Article
System: The UNT Digital Library
Border Security: The San Diego Fence (open access)

Border Security: The San Diego Fence

None
Date: June 25, 2007
Creator: Nuñez-Neto, Blas
Object Type: Report
System: The UNT Digital Library
Bpm Calibration Independent Lhc Optics Correction (open access)

Bpm Calibration Independent Lhc Optics Correction

The tight mechanical aperture for the LHC imposes severe constraints on both the beta and dispersion beating. Robust techniques to compensate these errors are critical for operation of high intensity beams in the LHC. We present simulations using realistic errors from magnet measurements and alignment tolerances in the presence of BPM noise. Correction reveals that the use of BPM calibration and model independent observables are key ingredients to accomplish optics correction. Experiments at RHIC to verify the algorithms for optics correction are also presented.
Date: June 25, 2007
Creator: Calaga, R.; Tomas, R.; Giovannozzi, M. & Zimmermann, F.
Object Type: Article
System: The UNT Digital Library
The Carbon Cycle: Implications for Climate Change and Congress (open access)

The Carbon Cycle: Implications for Climate Change and Congress

Defines the carbon cycle and how humans contribute to global climate change despite adding 5% to the total amount of carbon dioxide released from the oceans and land surfaces to the atmosphere each year. Humans affecr the global carbon cycle by transferring fossil carbon to the atmosphere and CO2 from burning fossil fuels has remained in the atmosphere for the past 250 years. How Congress is looking to address the issue.
Date: June 25, 2007
Creator: Folger, Peter
Object Type: Report
System: The UNT Digital Library
CHALLENGES ENCOUNTERED DURING THE PROCESSING OF THE BNL ERL 5 CELL ACCELERATING CAVITY (open access)

CHALLENGES ENCOUNTERED DURING THE PROCESSING OF THE BNL ERL 5 CELL ACCELERATING CAVITY

One of the key components for the Energy Recovery Linac being built by the Electron cooling group in the Collider Accelerator Department is the 5 cell accelerating cavity which is designed to accelerate 2 MeV electrons from the gun up to 15-20 MeV, allow them to make one pass through the ring and then decelerate them back down to 2 MeV prior to sending them to the dump. This cavity was designed by BNL and fabricated by AES in Medford, NY. Following fabrication it was sent to Thomas Jefferson Lab in VA for chemical processing, testing and assembly into a string assembly suitable for shipment back to BNL for integration into the ERL. The steps involved in this processing sequence will be reviewed and the deviations from processing of similar SRF cavities will be discussed. The lessons learned from this process are documented to help future projects where the scope is different from that normally encountered.
Date: June 25, 2007
Creator: Burrill, A.
Object Type: Article
System: The UNT Digital Library
Collective Effects in the NSLS-II Storage Ring. (open access)

Collective Effects in the NSLS-II Storage Ring.

A new high-brightness synchrotron light source (NSLS-II) is under design at BNL. The 3-GeV NSLS-II storage ring has a double-bend achromatic lattice with damping wigglers installed in zero-dispersion straights to reduce the emittance below 1nm. In this paper, we present an overview of the impact of collective effects upon the performance of the storage ring. Subjects discussed include instability thresholds, Touschek lifetime and intra-beam scattering.
Date: June 25, 2007
Creator: Krinsky, S.; Bengtsson, J.; Berg, J. S.; Blaskiewicz, M.; Blednykh, A.; Guo, W. et al.
Object Type: Article
System: The UNT Digital Library
Collective Effects in the Rhic-Ii Electron Cooler (open access)

Collective Effects in the Rhic-Ii Electron Cooler

Electron cooling at RHIC-I1 upgrade imposes strict requirements on the quality of the electron beam at the cooling section. Beam current dependent effects such as the space charge, wake fields, CSR in bending magnets, trapped ions, etc., will tend to spoil the beam quality and decrease the cooling efficiency. In this paper, we estimate the defocusing effect of the space charge at the cooling section and describe our plan to compensate the defocusing space charge force by focusing solenoids. We also estimate the energy and emittance growth cased by wake fields. Finally, we discuss ion trapping in the electron cooler and consider different techniques to minimize the effect of ion trapping.
Date: June 25, 2007
Creator: Pozdeyev, E.; Ben-Zvi, Ilan; Fedotov, A.; Kayran, D.; Litvinenko, V. & Wang, G.
Object Type: Article
System: The UNT Digital Library
Colliding pulse injection experiments in non-collinear geometryfor controlled laser plasma wakefield acceleration of electrons (open access)

Colliding pulse injection experiments in non-collinear geometryfor controlled laser plasma wakefield acceleration of electrons

An optical injection scheme for a laser-plasma basedaccelerator which employs a non-collinear counter-propagating laser beamto push background electrons in the focusing and acceleration phase viaponderomotive beat with the trailing part of the wakefield driver pulseis discussed. Preliminary experiments were performed using a drive beamof a_0 = 2.6 and colliding beam of a_1 = 0.8 both focused on the middleof a 200 mu m slit jet backed with 20 bar, which provided ~; 260 mu mlong gas plume. The enhancement in the total charge by the collidingpulse was observed with sharp dependence on the delay time of thecolliding beam. Enhancement of the neutron yield was also measured, whichsuggests a generation of electrons above 10 MeV.
Date: June 25, 2007
Creator: Toth, Carl B.; Esarey, Eric H.; Geddes, Cameron G.R.; Leemans,Wim P.; Nakamura, Kei; Panasenko, Dmitriy et al.
Object Type: Article
System: The UNT Digital Library
A Complete Scheme for Ionization Cooling for a Muon Collider. (open access)

A Complete Scheme for Ionization Cooling for a Muon Collider.

A complete scheme for production and cooling a muon beam for three specified muon colliders is presented. Parameters for these muon colliders are given. The scheme starts with the front end of a proposed neutrino factory that yields bunch trains of both muon signs. Emittance exchange cooling in slow helical lattices reduces the longitudinal emittance until it becomes possible to merge the trains into single bunches, one of each sign. Further cooling in all dimensions is applied to the single bunches in further slow helical lattices. Final transverse cooling to the required parameters is achieved in 50 T solenoids using high TC superconductor at 4 K. Preliminary simulations of each element are presented.
Date: June 25, 2007
Creator: Palmer, R. B.; Berg, J. S.; Fernow, R. C.; Gallardo, J. C.; Kirk, H. G.; Alexahin, Y. et al.
Object Type: Article
System: The UNT Digital Library
Composition and Technical Basis for K Basin Settler Sludge Simulant for Inspection, Retrieval, and Pump Testing (open access)

Composition and Technical Basis for K Basin Settler Sludge Simulant for Inspection, Retrieval, and Pump Testing

This report provides the formulation and technical basis for a K Basin Settler Tank Sludge simulant that will be used by the K Basin Closure Project (KBC) to test and develop equipment/approaches for Settler Tank sludge level measurement and retrieval in a mock-up test system of the actual Settler Tanks. The sludge simulant may also be used to demonstrate that the TOYO high pressure positive displacement pump design (reversing valves and hollow balls) is suitable for transfer of Settler Tank sludge from the K West (KW) Basin to the Cold Vacuum Drying Facility (CVDF) (~500 ft). As requested the by the K Basins Sludge Treatment Project (STP) the simulant is comprised of non-radioactive (and non-uranium) constituents.
Date: June 25, 2007
Creator: Schmidt, Andrew J. & Zacher, Alan H.
Object Type: Report
System: The UNT Digital Library
Conceptual Design of the NSLS-II Injection System. (open access)

Conceptual Design of the NSLS-II Injection System.

We present the conceptual design of the NSLS-II injection system [1,2]. The injection system consists of a low-energy linac, booster and transport lines. We review two different injection system configurations; a booster located in the storage ring tunnel and a booster housed in a separate building. We briefly discuss main parameters and layout of the injection system components.
Date: June 25, 2007
Creator: Shaftan, T.; Rose, T.; Pinayev, I.; Heese, R.; Bengtsson, J.; Skaritka, J. et al.
Object Type: Article
System: The UNT Digital Library
Conservation and the 2007 Farm Bill (open access)

Conservation and the 2007 Farm Bill

None
Date: June 25, 2007
Creator: Zinn, Jeffrey A.
Object Type: Report
System: The UNT Digital Library
Coupling Impedance of Cesr-B Rf Cavity for the Nsls-Ii Storage Ring. (open access)

Coupling Impedance of Cesr-B Rf Cavity for the Nsls-Ii Storage Ring.

CESR-B type superconducting cavities are under consideration for acceleration of the electron beam in the 3GeV NSLS-II storage ring. In this paper we present detailed investigation of longitudinal and transverse impedance of CESR-B cavity and transitions. Ferrite material is included in impedance analysis. Its effect on short range wake potential has been studied using GdfidL code. The summary results of loss factors and kick factors are presented for a 3mm rms bunch length.
Date: June 25, 2007
Creator: Blednykh, A.; Krinsky, S. & Rose, J.
Object Type: Article
System: The UNT Digital Library
Design and Performance of the Matching Beamline Between the Bnl Ebis and an Rfq. (open access)

Design and Performance of the Matching Beamline Between the Bnl Ebis and an Rfq.

A part of a new EBIS-based heavy ion preinjector, the low energy beam transport (LEBT) section between the high current EBIS and the RFQ is a challenging design, because it must serve many functions. In addition to the requirement to provide an efficient matching between the EBIS and the RFQ, this line must serve as a fast ''switchyard'', allowing singly charged ions from external sources to be transported into the EBIS trap region, and extracted, highly charged ions to be deflected to off-axis diagnostics (time-of-flight or emittance). The space charge of the 5-10 mA extracted heavy ion beam is a major consideration in the design, and the space charge force varies for different ion beams having Q/m from 1-0.16. The line includes electrostatic lenses, spherical and parallel-plate deflectors, magnetic solenoid, and diagnostics for measuring current, charge state distributions, emittance, and profile. A prototype of this beamline has been built, and results of tests are presented.
Date: June 25, 2007
Creator: Alessi, J.; Beebe, E.; Brodowski, J.; Kponou, A.; Okamura, M.; Pikin, A. et al.
Object Type: Article
System: The UNT Digital Library
Design and Performance of the Matching Beamline Between the BNL EBIS and an RFQ. (open access)

Design and Performance of the Matching Beamline Between the BNL EBIS and an RFQ.

This report addresses the design and performance of the matching beamline between the BNL EBIS and an RFQ.
Date: June 25, 2007
Creator: Alessi,J.; Beebe, E.; Brodowski, J.; Kponou, A.; Okamura, M.; Pikin, A. et al.
Object Type: Article
System: The UNT Digital Library
Design of a Thin Quadrupole to Be Used in the Ags Synchrotron (open access)

Design of a Thin Quadrupole to Be Used in the Ags Synchrotron

The Alternating Gradient Synchrotron (AGS) employs two partial helical snakes[l] to preserve the polarization of the proton beam during acceleration. In order to compensate for the focusing effect of the partial helical snakes on the beam optics in the AGS during acceleration of the beam, we introduced eight quadrupoles in straight sections of the AGS at the proximity of the partial snakes. At injection energies, the strength of each quad is set at a high value, and is ramped down to zero as the effect of the snakes diminishes by the square of beam's rigidity. Four of the eight compensation quadrupoles had to be placed in very short straight sections -30 cm in length, therefore the quadruples had be thin with an overall length of less than 30 cm. In this paper we will discus: (a) the mechanical and magnetic specifications of the ''thin'' quadrupole. (b) the method to minimize the strength of the dodecapole harmonic, (c) the method to optimize the thickness of the laminations that the magnet iron is made, (d) mechanical tolerances of the magnet, (e) comparison of the measured and calculated magnetic multipoles of the quadrupole.
Date: June 25, 2007
Creator: Tsoupas, N.; Ahrens, L.; Alforque, R.; Bai, M.; Brown, K.; Courant, E. et al.
Object Type: Article
System: The UNT Digital Library
DESIGN OF BEAM TRANSFER LINES FOR THE NSLS II (open access)

DESIGN OF BEAM TRANSFER LINES FOR THE NSLS II

The NSLS-II light source which is a proposed facility to be built at Brookhaven National Laboratory utilizes two synchrotron accelerator rings: the booster and the Storage ring (SR). Designing the NSLS-11 injector we considered two options for the booster layout, where the rings either (a) share the same tunnel, but placed at different horizontal planes or (b) booster is located in a separate building. The booster which accepts beam from the linac, accelerates the electron beam to an energy of 3.0 GeV and the beam is extracted to the Booster to Storage Ring (BtS) transport line which transports the beam and injects it into the SR ring. The design procedure for each of the two options of the BtS line and other details about the optics and the magnetic elements of the line are presented in this paper.
Date: June 25, 2007
Creator: Tsoupas, N.; Rose, J.; Pinayev, I.; Shaftan, T. & Stelmach, C.
Object Type: Article
System: The UNT Digital Library
Diagnostics of Bnl Erl (open access)

Diagnostics of Bnl Erl

The ERL Prototype project is currently under development at the Brookhaven National Laboratory. The ERL is expected to demonstrate energy recovery of high-intensity beams with a current of up to a few hundred milliamps, while preserving the emittance of bunches with a charge of a few nanocoulombs produced by a high-current SRF gun. To successfully accomplish this task the machine will include beam diagnostics that will be used for accurate characterization of the three dimensional beam phase space at the injection and recirculation energies, transverse and longitudinal beam matching, orbit alignment, beam current measurement, and machine protection. This paper outlines requirements on the ERL diagnostics and describes its setup and modes of operation.
Date: June 25, 2007
Creator: Pozdeyev, E.; Ben-Zvi, Ilan; Cameron, P.; Gassner, D.; Kayran, D. & Al., Et
Object Type: Article
System: The UNT Digital Library
Direct Drive Heavy-Ion-Beam Inertial Fusion at High Coupling Efficiency (open access)

Direct Drive Heavy-Ion-Beam Inertial Fusion at High Coupling Efficiency

Issues with coupling efficiency, beam illumination symmetry and Rayleigh Taylor (RT) instability are discussed for spherical heavy-ion-beam-driven targets with and without hohlraums. Efficient coupling of heavy ion beams to compress direct-drive inertial fusion targets without hohlraums is found to require ion range increasing several-fold during the drive pulse. One-dimensional implosion calculations using the LASNEX ICF target physics code shows the ion range increasing four-fold during the drive pulse to keep ion energy deposition following closely behind the imploding ablation front, resulting in high coupling efficiencies (shell kinetic energy/incident beam energy of 16 to 18%). Ways to increase beam ion range while mitigating Rayleigh-Taylor instabilities are discussed for future work.
Date: June 25, 2007
Creator: Logan, B. Grant; Logan, B. Grant; Perkins, L.J. & Barnard, J.J.
Object Type: Article
System: The UNT Digital Library
DISPERSION TOLERANCE CALCULATION FOR NSLS-II. (open access)

DISPERSION TOLERANCE CALCULATION FOR NSLS-II.

In this paper we discuss the effect on the emittance of the residual dispersion in the insertion devices. The dispersion in the straights could be generated by the lattice error, trim dipole, and insertion device. The effect on the emittance is examined, and the dispersion tolerances are given for the NSLS-11.
Date: June 25, 2007
Creator: LIN,F. & GUO, W.
Object Type: Article
System: The UNT Digital Library