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G. Marr,
L. Ahrens,
M. Bai, J. Beebe-Wang,
I. Blackler,
M. Blaskiewicz,
J.M. Brennan,
K.A. Brown,
D. Bruno,
J. Butler, [......],
P. Thieberger,
D. Trbojevic,
N. Tsoupas,
J.E. Tuozzolo,
B. VanKuik,
G. Wang,
M. Wilinski,
A. Zaltsman,
K. Zeno,
S.Y. Zhang
[show abstract]
[hide abstract]
ABSTRACT: Following the Fiscal Year (FY) 2010 (Run-10) Relativistic Heavy Ion Collider (RHIC) Au+Au run, RHIC experiment upgrades sought to improve detector capabilities. In turn, accelerator improvements were made to improve the luminosity available to the experiments for this run (Run-11). These improvements included: a redesign of the stochastic cooling systems for improved reliability; a relocation of 'common' RF cavities to alleviate intensity limits due to beam loading; and an improved usage of feedback systems to control orbit, tune and coupling during energy ramps as well as while colliding at top energy. We present an overview of changes to the Collider and review the performance of the collider with respect to instantaneous and integrated luminosity goals. At the conclusion of the FY 2011 polarized proton run, preparations for heavy ion run proceeded on April 18, with Au+Au collisions continuing through June 28. Our standard operations at 100 GeV/nucleon beam energy was bracketed by two shorter periods of collisions at lower energies (9.8 and 13.5 GeV/nucleon), continuing a previously established program of low and medium energy runs. Table 1 summarizes our history of heavy ion operations at RHIC.
09/2011
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D. Boer,
M. Diehl,
R. Milner,
R. Venugopalan,
W. Vogelsang,
A. Accardi,
E. Aschenauer,
M. Burkardt,
R. Ent,
V. Guzey, [......],
S. Webb,
C Weiss,
Q Wu,
B. -W. Xiao,
W Xu,
B. Yunn,
A. Zelenski,
Y Zhang,
J Zhou,
P. Zurita
[show abstract]
[hide abstract]
ABSTRACT: This report is based on a ten-week program on "Gluons and the quark sea at
high-energies", which took place at the Institute for Nuclear Theory in Seattle
in Fall 2010. The principal aim of the program was to develop and sharpen the
science case for an Electron-Ion Collider (EIC), a facility that will be able
to collide electrons and positrons with polarized protons and with light to
heavy nuclei at high energies, offering unprecedented possibilities for
in-depth studies of quantum chromodynamics. This report is organized around
four major themes: i) the spin and flavor structure of the proton, ii)
three-dimensional structure of nucleons and nuclei in momentum and
configuration space, iii) QCD matter in nuclei, and iv) Electroweak physics and
the search for physics beyond the Standard Model. Beginning with an executive
summary, the report contains tables of key measurements, chapter overviews for
each of the major scientific themes, and detailed individual contributions on
various aspects of the scientific opportunities presented by an EIC.
08/2011;
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D. Boer,
M. Diehl,
R. Milner,
R. Venugopalan,
W. Vogelsang,
A. Accardi,
E. Aschenauer,
M. Burkardt,
R. Ent,
V. Guzey, [......],
S. Webb,
C. Weiss,
Q. Wu,
B.-W. Xiao,
W. Xu,
B. Yunn,
A. Zelenski,
Y. Zhang,
J. Zhou,
P. Zurita
[show abstract]
[hide abstract]
ABSTRACT: This report is based on a ten-week program on "Gluons and the quark sea
at high-energies", which took place at the Institute for Nuclear Theory
in Seattle in Fall 2010. The principal aim of the program was to develop
and sharpen the science case for an Electron-Ion Collider (EIC), a
facility that will be able to collide electrons and positrons with
polarized protons and with light to heavy nuclei at high energies,
offering unprecedented possibilities for in-depth studies of quantum
chromodynamics. This report is organized around four major themes: i)
the spin and flavor structure of the proton, ii) three-dimensional
structure of nucleons and nuclei in momentum and configuration space,
iii) QCD matter in nuclei, and iv) Electroweak physics and the search
for physics beyond the Standard Model. Beginning with an executive
summary, the report contains tables of key measurements, chapter
overviews for each of the major scientific themes, and detailed
individual contributions on various aspects of the scientific
opportunities presented by an EIC.
07/2011;
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V. Ptitsyn,
E.C. Aschenauer,
M. Bai, J. Beebe-Wang,
S.A. Belomestnykh,
I. Ben-Zvi,
M. Blaskiewicz,
R. Calaga,
X. Chang,
A.V. Fedotov, [......],
D. Trbojevic,
N. Tsoupas,
J.E. Tuozzolo,
G. Wang,
Q. Wu,
W. Xu,
A. Zaltsman,
E. Podzeyev,
E. Tsentalovic,
L. Hammons
[show abstract]
[hide abstract]
ABSTRACT: We present the design of future high-energy high-luminosity electron-hadron collider at RHIC called eRHIC. We plan on adding 20 (potentially 30) GeV energy recovery linacs to accelerate and to collide polarized and unpolarized electrons with hadrons in RHIC. The center-of-mass energy of eRHIC will range from 30 to 200 GeV. The luminosity exceeding 1034 cm-2 s-1 can be achieved in eRHIC using the low-beta interaction region with a 10 mrad crab crossing. We report on the progress of important eRHIC R&D such as the high-current polarized electron source, the coherent electron cooling and the compact magnets for recirculating passes. A natural staging scenario of step-by-step increases of the electron beam energy by builiding-up of eRHIC's SRF linacs and a potential of adding polarized positrons are also presented.
Particle Accelerator Conference, 2011, New York, NY; 03/2011
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K.A. Drees,
L. Ahrens,
M. Bai, J. Beebe-Wang,
I.M.C. Blackler,
M. Blaskiewicz,
K.A. Brown,
M. Brennan,
D. Bruno,
J. Butler, [......],
S. Tepikian,
P. Thieberger,
D. Trbojevic,
N. Tsoupas,
J. Tuozzolo,
B. van Kuik,
M. Wilinski,
A. Zaltsman,
K. Zeno,
S.Y. Zhang
[show abstract]
[hide abstract]
ABSTRACT: As part of the search for a phase transition or critical point on the QCD phase diagram, an energy scan including 5 different energy settings was performed during the 2010 RHIC heavy ion run. While the top beam energy for heavy ions is at 100 GeV/n and the lowest achieved energy setpoint was significantly below RHICs injection energy of approximately 10 GeV/n, we also provided beams for data taking in a medium energy range above injection energy and below top beam energy. This paper reviews RHIC experience and challenges for RHIC medium energy operations that produced full experimental data sets at beam energies of 31.2 GeV/n and 19.5 GeV/n. The medium energy AuAu run covered two beam energies, both above the RHIC injection energy of 9.8 GeV but well below the standard store energy of 100 GeV (see table 1). The low energy and full energy runs with heavy ions in FY10 are summarized in [1] and [2]. Stochastic Cooling ([3]) was only used for 100 GeV beams and not used in the medium energy run. The efficiency of the transition from 100 GeV operation to 31.2 GeV and then to 19.5 GeV was remarkable. Setup took 32 h and 19 h respectively for the two energy settings. The time in store, defined to be the percentage of time RHIC provides beams in physics conditions versus calendar time, was approximately 52% for the entire FY10 heavy ion run. In both medium energy runs it was well above this average, 68% for 31.5 GeV and 82% for 19.5 GeV. For both energies RHIC was filled with 111 bunches with 1.2 10{sup 9} and 1.3 10{sup 9} ions per bunch respectively.
03/2011
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[show abstract]
[hide abstract]
ABSTRACT: The existence of multipole components in the dipole and quadrupole magnets is one of the factors limiting the beam stability in the RHIC operations. So, a realistic nonlinear model is crucial for understanding the beam behavior and to achieve the ultimate performance in RHIC. A procedure is developed to build a non-linear model using the available multipole component data obtained from measurements of RHIC magnets. We first discuss the measurements performed at different stages of manufacturing of the magnets in relation to their current state in RHIC. We then describe the procedure to implement these measurement data into tracking models, including the implementation of the multipole feed down effect due to the beam orbit offset from the magnet center. Finally, the field quality analysis in the RHIC interaction regions (IR) is presented.
Particle Accelerator Conference, 2007. PAC. IEEE; 07/2007
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C. Montag,
M. Bai, J. Beebe-Wang,
M. Blaskiewicz,
R. Calaga,
W. Fischer,
A. Jain,
Y. Luo,
N. Malitsky,
T. Roser,
S. Tepikian
[show abstract]
[hide abstract]
ABSTRACT: To achieve the RHIC polarized proton enhanced luminosity goal of 150 - 10<sup>30</sup> cm<sup>-2</sup>sec<sup>-1</sup> on average in stores at 250 GeV, the luminosity needs to be increased by a factor of 3 compared to what was achieved in 2006. Since the number of bunches is already at its maximum of 111, limited by the injection kickers and the experiments' time resolution, the luminosity can only be increased by either increasing the bunch intensity and/or reducing the beam emittance. This leads to a larger beam-beam tuneshift parameter. Operations during 2006 has shown that the beam-beam interaction is already dominating the luminosity lifetime. To overcome this limitation, a near-integer working point is under study. We will present recent results of these studies.
Particle Accelerator Conference, 2007. PAC. IEEE; 07/2007
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[show abstract]
[hide abstract]
ABSTRACT: An 8 GeV superconducting linear accelerator (SCL) has been proposed [1] as a single stage H<sup>-</sup> injector into the Main Injector (MI) synchrotron . This would be the highest energy H- multi-turn injection system in the world. The conceptual design of an injection system has been further refined by addressing transverse phase space painting issues, chicane dipole fields and foil location, foil temperature issues, and initial longitudinal phase space painting simulations. We present the current state of design.
Particle Accelerator Conference, 2007. PAC. IEEE; 07/2007
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[show abstract]
[hide abstract]
ABSTRACT: With the updated multipole magnet field errors in the interaction regions (IRs), detailed dynamic aperture studies are carried out around the current RHIC polarized proton (pp) working point. The beam parameters and beta*s are similar to those proposed for the next pp run. The effects on the dynamic apertures from nonlinear corrections, such as multipole field error correction in the IRs, second order chromaticity correction and horizontal third order resonance correction are evaluated. The sextupole components in the arc dipoles and the observed tune ripples are also considered.
Particle Accelerator Conference, 2007. PAC. IEEE; 07/2007
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A. Drees,
L. Ahrens,
J. Alessi,
M. Bai,
D. Barton, J. Beebe-Wang,
M. Blaskiewicz,
K. Brown,
M. Brennan,
D. Bruno, [......],
T. Satogata,
C. Schultheiss,
F. Severino,
K. Smith,
S. Tepikian,
D. Trbojevic,
N. Tsoupas,
J. Tuozzolo,
A. Zaltsman,
S.Y. Zhang
[show abstract]
[hide abstract]
ABSTRACT: After the last successful RHIC Au-Au run in 2004 (Run-4), RHIC experiments now require significantly enhanced luminosity to study very rare events in heavy ion collisions. RHIC has demonstrated its capability to operate routinely above its design average luminosity per store of 2times10<sup>26</sup> cm<sup>-2</sup> s<sup>-1</sup>. In Run-4 we already achieved 2.5 times the design luminosity in RHIC. This luminosity was achieved with only 40% of the total possible number of bunches filled, and with beta* = 1 m. However, the goal is to reach 4 times the design luminosity, an average of 8times10<sup>26</sup> cm<sup>-2</sup> s<sup>-1</sup>, by reducing the beta* value and increasing the number of bunches to the accelerator maximum of 111. In addition, the average time at store was expected to be increased by a factor of 1.1 to about 60% of calendar time. We present an overview of the changes that increased the instantaneous luminosity, luminosity lifetime and integrated luminosity of RHIC Au-Au operations during Run-7 even though the goal of 60% time at store could not be reached.
Particle Accelerator Conference, 2007. PAC. IEEE; 07/2007
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T. Shaftan,
J. Rose,
I. Pinayev,
R. Heese,
J. Bengtsson,
J. Skaritka,
W. Meng,
S. Ozaki,
R. Meier,
C. Stelmach, [......],
G. Ganetis,
H.C. Hseuh,
E.D. Johnson,
N. Tsoupas,
W. Guo, J. Beebe-Wang,
A.U. Luccio,
L.H. Yu,
D. Raparia,
D. Wang
[show abstract]
[hide abstract]
ABSTRACT: 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.
Particle Accelerator Conference, 2007. PAC. IEEE; 07/2007
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M. Bai,
L. Ahrens,
I.G. Alekseev,
J. Alessi, J. Beebe-Wang,
M. Blaskiewicz,
A. Bravar,
J.M. Brennan,
K. Brown,
D. Bruno, [......],
D.N. Svirida,
D. Trbojevic,
N. Tsoupas,
J. Tuozzolo,
M. Wilinski,
S. Tepikian,
A. Zaltsman,
A. Zelenski,
K. Zeno,
S.Y. Zhang
[show abstract]
[hide abstract]
ABSTRACT: The relativistic heavy ion collider (RHIC) as the first high energy polarized proton collider was designed to provide polarized proton collisions at a maximum beam energy of 250 GeV. It has been providing collisions at a beam energy of 100 GeV 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 to examine the impact of these strong intrinsic spin resonances on polarization survival and the tolerance for vertical orbit distortions. Polarized protons were accelerated to the record energy of 250 GeV in RHIC with a polarization of 46% measured at 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 to orbit distortions.
Particle Accelerator Conference, 2007. PAC. IEEE; 07/2007
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M Bai,
T Roser,
L Ahrens,
I G Alekseev,
J Alessi, J Beebe-Wang,
M Blaskiewicz,
A Bravar,
J M Brennan,
D Bruno, [......],
T Satogata,
E Stephenson,
D Svirida,
S Tepikian,
D Trbojevic,
N Tsoupas,
T Wise,
A Zelenski,
K Zeno,
S Y Zhang
[show abstract]
[hide abstract]
ABSTRACT: The Brookhaven Relativistic Heavy Ion Collider (RHIC) has been providing collisions of polarized protons at a beam energy of 100 GeV since 2001. Equipped with two full Siberian snakes in each ring, polarization is preserved during acceleration from injection to 100 GeV. However, the intrinsic spin resonances beyond 100 GeV are about a factor of 2 stronger than those below 100 GeV making it important to examine the impact of these strong intrinsic spin resonances on polarization survival and the tolerance for vertical orbit distortions. Polarized protons were first accelerated to the record energy of 205 GeV in RHIC with a significant polarization measured at top energy in 2005. This Letter presents the results and discusses the sensitivity of the polarization survival to orbit distortions.
Physical Review Letters 06/2006; 96(17):174801. · 7.37 Impact Factor
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F. Wang,
M. Farkhondeh,
W. Franklin,
W. Graves,
R. Milner,
J. van der Laan,
C. Tschalaer,
D. Wang,
T. Zwart,
A. Zolfaghari, [......],
W.W. Mackay,
C. Montag,
B. Parker,
S. Peggs,
S. Ozaki,
V. Ptitsyn,
T. Roser,
S. Tepikian,
D. Trbojevic,
D.P. Barber
[show abstract]
[hide abstract]
ABSTRACT: The eRHIC ring-ring collider is the main design option for the future lepton-ion collider at Brookhaven National Laboratory. The baseline design is presented in the eRHIC Zero<sup>th</sup>-Order Design Report (ZDR) [1]. We report on progress made during the past year including possible interaction region design changes, upgrade efforts on RHIC (the ion ring), and results of a new design study on the e-ring. The interaction region revision is based on a new scheme for the main detector design. RHIC upgrades are being pursued to ensure luminosity and ion polarization goals of the ring-ring option in the baseline design will be met. Higher current operation of the lepton storage ring is under serious consideration as a result of better understanding of beam-beam interaction effects.
Particle Accelerator Conference, 2005. PAC 2005. Proceedings of the; 06/2005
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F. Pilat,
L. Ahrens,
M. Bai,
D.S. Barton, J. Beebe-Wang,
M. Blaskiewicz,
J.M. Brennan,
D. Bruno,
P. Cameron,
R. Connolly, [......],
S. Tepikian,
R. Tomas,
D. Trbojevic,
N. Tsoupas,
J. Tuozzolo,
K. Vetter,
A. Zaltsman,
K. Zeno,
S.Y. Zhang,
W. Zhang
[show abstract]
[hide abstract]
ABSTRACT: The 5<sup>th</sup>year of RHIC operations, started in November 2004 and expected to last till June 2005, consists of a physics run with Cu-Cu collisions at 100 GeV/u followed by one with polarized protons (pp) at 100 GeV [1]. We will address here the overall performance of the RHIC complex used for the first time as a Cu-Cu collider, and compare it with previous operational experience with Au, PP and asymmetric d-Au collisions. We will also discuss operational improvements, such as a squeeze to 85cm in the high luminosity interaction regions from the design value of 1m, system improvements, machine performance and limitations, and address reliability and uptime issues.
Particle Accelerator Conference, 2005. PAC 2005. Proceedings of the; 06/2005
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[show abstract]
[hide abstract]
ABSTRACT: The requirement for low beam loss is very important both to protect the beam component, and to make the hands-on maintenance possible. In this report, the design considerations to achieving high intensity and low loss will be presented. We start by specifying the beam loss limit at every physical process followed by the proper design and parameters for realizing the required goals. The process considered in this paper include the emittance growth in the linac, the H<sup>-</sup>injection, the transition crossing, the coherent instabilities and the extraction losses,
Particle Accelerator Conference, 2005. PAC 2005. Proceedings of the; 06/2005
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[show abstract]
[hide abstract]
ABSTRACT: The electron-ion collider eRHIC [1] currently under study at BNL consists of a 10GeV high intensity electron beam facility to be added to the existing RHIC complex. The interaction region of this facility has to provide the required low-beta focusing while accommodating the synchrotron radiation generated by beam separation close to the interaction point. In the current design, the synchrotron radiation caused by 10GeV electrons bent by separator dipole magnets will be guided through the interaction region and dumped 5m downstream. However, it is unavoidable to stop a fraction of the photons at the septum where the electron and ion vacuum systems are separated. In order to protect the septum and minimize the backward synchrotron radiation, an absorber and collimation system will be employed. In this paper, we first present the overview of the current design of the eRHIC interaction region with special emphasis on the synchrotron radiation. Then the initial design of the absorber, including its geometrical and physical property, will be described. Finally, our initial investigation of synchrotron radiation in the eRHIC interaction region, especially a simulation of the backward scattering from the absorber, will be presented.
Particle Accelerator Conference, 2005. PAC 2005. Proceedings of the; 06/2005
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[show abstract]
[hide abstract]
ABSTRACT: Earlier works, including a recent one at BNL, demonstrated that PET is a promising technique to verify the dose distribution of proton therapy, which is increasingly used in radiation oncology because the dose conforms more tightly to the tumor than common x-ray radiation therapy. Proton therapy produces positron-emitting isotopes along the beam path, allowing the therapy dose distribution to be imaged by PET as a form of quality assurance of the treatment. This is especially important when treating inhomogeneous organs such as the lungs or the head-and-neck, where the calculation of the expected dose distribution for treatment planning is more difficult. In this paper, we present Monte Carlo simulations of the yield of positron emitters produced by proton beams up to 250 MeV, followed by statistically realistic Monte Carlo simulation of the images expected from a clinical PET scanner. The emphasis of this study is to accurately predict the positron emitter distribution and to determine the quality of the PET signal in the region near the Bragg peak which is critical to the success of PET imaging for verification of proton beam location and dosimetry. In this paper, we also demonstrate that the image results depend strongly on the available nuclear reaction cross section data. We determine quantitatively the differences in the calculated positron emitter yields resulting from four different sets of input nuclear reaction cross section data. They are compared to the simulated distributions of positron emitter productions and absorbed proton energies.
Nuclear Science Symposium Conference Record, 2003 IEEE; 11/2003
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T. Satogata,
L. Ahrens,
M. Bai, J. Beebe-Wang,
M. Blaskiewicz,
J.M. Brennan,
K.A. Brown,
D. Bruno,
P. Cameron,
J. Cardona, [......],
C. Montag,
F. Pilat,
V. Ptitsyn,
T. Roser,
K. Smith,
S. Tepikian,
D. Trbojevic,
N. Tsoupas,
S.Y. Zhang,
J. van Zeijts
[show abstract]
[hide abstract]
ABSTRACT: Deuteron and gold beams have been accelerated to a collision energy of √s = 200 GeV/u in the Relativistic Heavy Ion Collider (RHIC), providing the first asymmetric-species collisions of this complex. Necessary changes for this mode of operation include new ramping software and asymmetric crossing angle geometries. This paper reviews machine performance, problems encountered and their solutions, and accomplishments during the 16 weeks of ramp-up and operations.
Particle Accelerator Conference, 2003. PAC 2003. Proceedings of the; 06/2003
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H. Huang,
L. Ahrens,
J.G. Alessi,
I. Alekseev,
M. Bai, J. Beebe-Wang,
S. Brarvar,
M. Brennan,
K.A. Brown,
G. Bunce, [......],
D. Svirida,
S. Tepikian,
D. Trbojevic,
N. Tsoupas,
D. Underwood,
J. van Zeijts,
J. Wood,
A. Zelenski,
K. Zeno,
S.Y. Zhang
[show abstract]
[hide abstract]
ABSTRACT: Polarized proton beam has been accelerated and stored at 100GeV in Relativistic Heavy Ion Collider (RHIC) to study spin effects in the hadronic reactions. The essential equipment includes four Siberian snakes and eight spin rotators in two RHIC rings, a partial snake in the AGS, fast relative polarimeters, and ac dipoles in the AGS and RHIC. This paper summarizes the performance of RHIC as a polarized proton collider and of AGS as the injector to RHIC.
Particle Accelerator Conference, 2003. PAC 2003. Proceedings of the; 06/2003
