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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: Three-dimensional stochastic cooling of 100 GeV/nucleon gold beams has been achieved in the Relativistic Heavy Ion Collider (RHIC). We discuss the physics and technology of the cooling systems and present results with a beam. A factor of 2 increase in luminosity was achieved and another factor of 2 is expected.
Physical Review Letters 08/2010; 105(9):094801. · 7.37 Impact Factor
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V.N. Litvinenko,
D. Beavis,
I. Ben-Zvi, M. Blaskiewicz,
A. Burrill,
R. Calaga,
P. Cameron,
X. Chang,
A. Drees,
G. Ganetis, [......],
H. Bluem,
M. Cole,
D. Holmes,
J. Rathke,
T. Schultheiss,
A. Todd,
J. Delayen,
L. Funk,
L. Phillips,
J. Preble
[show abstract]
[hide abstract]
ABSTRACT: Collider Accelerator Department at BNL is in the final stages of developing the 20-MeV R and D energy recovery linac with super-conducting 2.5 MeV RF gun and single-mode super-conducting 5-cell RF linac. This unique facility aims to address many outstanding questions relevant for high current (up to 0.5 A of average current), high brightness energy-recovery linacs with novel ZigZag-type merger. Recent development in the R and D ERL plans include gun and 5-cell cavity (G5) test and possibility of using R and D ERL for proof-of-principle test of Coherent Electron Cooling at RHIC.
06/2008
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[show abstract]
[hide abstract]
ABSTRACT: Operational stochastic cooling of 100 GeV/nucleon gold beams has been achieved in the BNL Relativistic Heavy-Ion Collider. We discuss the physics and technology of the longitudinal cooling system and present results with the beams. A simulation algorithm is described and shown to accurately model the system.
Physical Review Letters 05/2008; 100(17):174802. · 7.37 Impact Factor
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W Fischer, M Blaskiewicz,
J Brennan,
H Huang,
H -C Hseuh,
V Ptitsyn,
T Roser,
P Thieberger,
D Trbojevic,
J Wei,
S Zhang,
U Iriso
Physical Review Special Topics - Accelerators and Beams 04/2008; 11(4):1-18. · 1.52 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: The future relativistic electron hadron collider: e-RHIC requires acceleration of electrons to 10 GeV with a possible upgrade to 20 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 a 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.
Particle Accelerator Conference, 2007. PAC. IEEE; 07/2007
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[show abstract]
[hide abstract]
ABSTRACT: The electron cooling beam has both coherent and incoherent effects to the circulating ion beam. The incoherent longitudinal cooling could reduce the ion beam energy spread and hence cause 'over-cooling' of the ion beam. Depending on the beam densities and cooling length, the coherent interaction between the ion and electron beam could either damp or anti-damp the ion coherent motions. Using the tracking codes, TRANFT, the threshold for 'over-cooling' has been found and compared with theoretical estimation. The transverse coherent effect of electron cooling has been implemented into the codes and its effect for the bunched ion beam is shown.
Particle Accelerator Conference, 2007. PAC. IEEE; 07/2007
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S. Krinsky,
J. Bengtsson,
J.S. Berg, M. Blaskiewicz,
A. Blednykh,
W. Guo,
N. Malitsky,
C. Montag,
B. Podobedov,
J. Rose,
N. Towne,
L.H. Yu,
F. Wang
[show abstract]
[hide abstract]
ABSTRACT: 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 1 nm. 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.
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: We use transverse beam transfer functions to measure tune distributions of colliding beams in RHIC. The tune has a distribution due to the beam-beam interaction, nonlinear magnetic fields - particularly in the interaction region magnets, and non-zero chromaticity in conjunction with momentum spread. The measured tune distributions are compared with calculations.
Particle Accelerator Conference, 2007. PAC. IEEE; 07/2007
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[show abstract]
[hide abstract]
ABSTRACT: Stochastic cooling of 100 GeV/nucleon bunched beams has been achieved in the Relativistic Heavy Ion Collider (RHIC). The physics and technology of the longitudinal cooling system are discussed, and plans for a transverse cooling system are outlined.
Particle Accelerator Conference, 2007. PAC. IEEE; 07/2007
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I. Ben-Zvi,
J. Alduino,
D. Barton,
D. Beavis, M. Blaskiewicz,
J. Brennan,
A. Burrill,
R. Calaga,
P. Cameron,
X. Chang, [......],
G. Bell,
D. Bruhwiler,
R. Busby,
J. Cary,
D. Dimitrov,
P. Messmer,
V. Ranjbar,
D. Smithe,
A. Sobol,
P. Stoltz
[show abstract]
[hide abstract]
ABSTRACT: The physics interest in a luminosity upgrade of RHIC requires the development of a cooling-frontier facility. Detailed calculations were made of electron cooling of the stored RHIC beams. This has been followed by beam dynamics simulations to establish the feasibility of creating the necessary electron beam. The electron beam accelerator will be a superconducting Energy Recovery Linac (ERL). An intensive experimental R&D program engages the various elements of the accelerator, as described by 24 contributions to the 2007 PAC.
Particle Accelerator Conference, 2007. PAC. IEEE; 07/2007
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L. Ahrens,
J. Alessi,
J. Benjamin, M. Blaskiewicz,
J.M. Brennan,
K.A. Brown,
C. Carlson,
W. Fischer,
C.J. Gardner,
J.W. Glenn, [......],
J. Morris,
F. Pilat,
T. Roser,
F. Severino,
K.S. Smith,
D. Steski,
P. Thieberger,
N. Tsoupas,
A. Zaltsman,
K. Zeno
[show abstract]
[hide abstract]
ABSTRACT: Gold ions for the 2007 run [1] 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 AGS,and a new bunch merging scheme in AGS have provided beam bunches with reduced longitudinal emittance for RHIC.
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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W. Fischer, M. Blaskiewicz,
M. Brennan,
H. Huang,
H.-C. Hseuh,
V. Ptitsyn,
T. Roser,
P. Thieberger,
D. Trbojevic,
J. Wei,
S.Y. Zhang,
U. Iriso
[show abstract]
[hide abstract]
ABSTRACT: Since 2001 RHIC has experienced electron cloud effects, which have limited the beam intensity. These include dynamic pressure rises - including pressure instabilities, tune shifts, a reduction of the stability threshold for bunches crossing the transition energy, and possibly incoherent emittance growth. We summarize the main observations in operation and dedicated experiments, as well as countermeasures including baking, NEG coated warm beam pipes, solenoids, bunch patterns, anti-grazing rings, pre-pumped cold beam pipes, scrubbing, and operation with long bunches. This article is a short version of [1].
Particle Accelerator Conference, 2007. PAC. IEEE; 07/2007
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V.N. Litvinenko,
J. Alduino,
D. Beavis,
I. Ben-Zvi, M. Blaskiewicz,
J.M. Brennan,
A. Burrill,
R. Calaga,
P. Cameron,
Xiangyun Chang, [......],
D. Holmes,
J. Rathke,
T. Schultheiss,
A. Todd,
B. Buckley,
J.R. Delayen,
L.W. Funk,
L. Phillips,
J.P. Preble,
G. Citver
[show abstract]
[hide abstract]
ABSTRACT: In this paper we present status and plans for the 20- MeV R&D energy recovery linac (ERL), which is under construction at Collider Accelerator Department at BNL. The facility is based on high current (up to 0.5 A of average current) super-conducting 2.5 MeV RF gun,single-mode super-conducting 5-cell RF linac and about 20-m long return loop with very flexible lattice. The R&D ERL, which is planned for commissioning in early 2009, aims to address many outstanding questions relevant for high current, high brightness energy-recovery linacs.
Particle Accelerator Conference, 2007. PAC. IEEE; 07/2007
