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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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L. Ahrens,
J. Alessi,
J. Benjamin,
M. Blaskiewicz,
J.M. Brennan,
K.A. Brown,
C. Carlson, J. DeLong,
C.J. Gardner,
J.W. Glenn, [......],
W.W. MacKay,
G. Marr,
J. Morris,
T. Roser,
F. Severino,
K.S. Smith,
D. Steski,
N. Tsoupas,
A. Zaltsman,
K. Zeno
[show abstract]
[hide abstract]
ABSTRACT: Copper ions for the 2005 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 these accelerators with copper are reviewed in this paper.
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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L. Ahrens,
J. Alessi,
J. Benjamin,
M. Blaskiewicz,
J.M. Brennan,
K.A. Brown,
C. Carlson, J. DeLong,
T. D'Ottavio,
B. Frak, [......],
J. Morris,
T. Roser,
T. Satogata,
G. Smith,
K.S. Smith,
D. Steski,
N. Tsoupas,
P. Thieberger,
K. Zeno,
S.Y. Zhang
[show abstract]
[hide abstract]
ABSTRACT: The RHIC 2003 Physics Run required collisions between gold ions and deuterons. The injector necessarily had to deliver adequate quality (transverse and longitudinal emittance) and quantity of both species. For gold this was a continuing evolution from past work. For deuterons it was new territory. For the filling of the RHIC the injector not only had to deliver quality beams but also had to switch between these species quickly. This paper details the collider requirements and our success in meeting these. Some details of the configurations employed are given.
Particle Accelerator Conference, 2003. PAC 2003. Proceedings of the; 06/2003
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[show abstract]
[hide abstract]
ABSTRACT: Operational aspects of the RHIC RF system are described. To date three different beam combinations have been collided for physics production: gold-gold, deuteron-gold, and proton-proton(polarized). To facilitate this flexibility the RF systems of the two rings are independent and self-sufficient. Techniques to cope with problems such as, injection/capture, beam loading, bunch shortening, and RF noise have evolved and are explained.
Particle Accelerator Conference, 2003. PAC 2003. Proceedings of the; 06/2003
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M. Brennan,
P. Cameron,
P. Cerniglia,
R. Connolly,
J. Cupolo,
W. Dawson,
C. Degen,
A. DellaPenna, J. DeLong,
A. Drees,
D. Gassner,
M. Kesselman,
R. Lee,
A. Marusic,
J. Mead,
R. Michnoff,
C. Schultheiss,
R. Sikora,
J. Van Zeijts
[show abstract]
[hide abstract]
ABSTRACT: Three basic tune measurement methods are employed in RHIC; kicked beam, Schottky, and phase‐locked loop. The kicked beam and 2GHz Schottky systems have been in operation since the first commissioning of circulating beam in RHIC in 1999. Preliminary PLL measurements utilizing a commercial off‐the‐shelf lockin amplifier were completed during that run, and the resonant BPM used in that system also delivered 230MHz Schottky spectra. With encouraging preliminary results and the thought of tune feedback in mind, a PLL tune system was implemented in the FPGA/DSP environment of the RHIC BPM system for the RHIC 2001 run. During that run this system functioned at the level of the present state‐of‐the‐art in tune measurement accuracy and resolution, and was successfully incorporated into a tune feedback system for use during acceleration. Each of the tune measurement systems has particular strengths and weaknesses. We present specific and comparative details of systems design and operation. In addition, we present detailed tune measurements and their utilization in the measurement of chromaticity and the implementation of tune feedback. Finally, we discuss planned upgrades for the RHIC 2003 run. © 2002 American Institute of Physics
AIP Conference Proceedings. 12/2002; 648(1):134-149.
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L. Ahrens,
J. Alessi,
W. van Asselt,
J. Benjamin,
M. Blaskiewicz,
J.M. Brennan,
K.A. Brown,
C. Carlson, J. Delong,
C.J. Gardner,
J.W. Glenn,
T. Hayes,
T. Roser,
K.S. Smith,
D. Steski,
N. Tsoupas,
K. Zeno,
S.Y. Zhang
[show abstract]
[hide abstract]
ABSTRACT: The recent successful commissioning and operation 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
Particle Accelerator Conference, 2001. PAC 2001. Proceedings of the 2001; 02/2001
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[show abstract]
[hide abstract]
ABSTRACT: During accumulation the RF beam current in the the Spallation
Neutron Source ring rises from 0 to 50 Amperes. A clean, 250 nanosecond
gap is needed for the extraction kicker risetime. Large momentum spread
and small peak current are needed to prevent instabilities and stopband
related losses. A robust RF system meeting these requirements has been
designed
Particle Accelerator Conference, 2001. PAC 2001. Proceedings of the 2001; 02/2001
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[show abstract]
[hide abstract]
ABSTRACT: To ensure minimal losses and to preserve longitudinal emmittance,
beam is transferred from the AGS to the RHIC bunch to bucket. This
requires precision frequency and phase control for synchronization and
kicker timing. The required precision is realized with a set of direct
digital synthesizers. Each synthesizer can be frequency and phase
modulated to align the AGS bunch to the target bucket in the RHIC
Particle Accelerator Conference, 2001. PAC 2001. Proceedings of the 2001; 02/2001
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P. Cameron,
P. Cerniglia,
R. Connolly,
J. Cupolo,
W.C. Dawson,
C. Degen,
A. Dellapenna, J. DeLong,
A. Drees,
A. Huhn,
M. Kesselman,
A. Marusic,
B. Oerter,
J. Mead,
C. Schultheiss,
R. Sikora,
J. van Zeijts
[show abstract]
[hide abstract]
ABSTRACT: Preliminary phase-locked loop betatron tune measurement results
were obtained during RHIC 2000 with a resonant Beam Position Monitor.
These results suggested the possibility of incorporating PLL tune
measurement into a tune feedback system for RHIC 2001. Tune feedback is
useful in a superconducting accelerator, where the machine cycle time is
long and inefficient acceleration due to resonance crossing is not
comfortably tolerated. This is particularly true with the higher beam
intensities planned for RHIC 2001. We present descriptions of a PLL tune
measurement system implemented in the DSP/FPGA environment of a RHIC BPM
electronics module and the feedback system into which the measurement is
incorporated to regulate tune. In addition, we present results from the
commissioning of this system during RHIC 2001
Particle Accelerator Conference, 2001. PAC 2001. Proceedings of the 2001; 02/2001
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[show abstract]
[hide abstract]
ABSTRACT: The super-conducting Relativistic Heavy Ion Collider (RHIC) with two separate rings and six combined interaction regions will provide collisions between equal and unequal heavy ion species up to Au ions in typically 60 bunches. The betatron tunes of the two beams are among the most important parameters to be measured. The tunes have to be acquired at any moment during accelerator operation and in particular during the acceleration process. At RHIC the tune measurement device (ARTUS) consists of a fast horizontal and vertical kicker magnet and a dedicated beam position monitor in each ring. The system layout is described and first experiences from operation is reported. © 2000 American Institute of Physics.
AIP Conference Proceedings. 11/2000; 546(1):341-348.
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K A Brown,
L Ahrens,
J M Brennan, J Delong,
C Gardner,
D Gassner,
J W Glenn,
Y Kotlyar,
I Marneris,
A Rusek,
N Tsoupas,
K Zeno
[show abstract]
[hide abstract]
ABSTRACT: The NASA Space Radiation Laboratory (NSRL) was constructed in collaboration with NASA for the purpose of performing radiation effect studies for the NASA space program. The results of commissioning of this new facility were reported in [1]. In this report we will describe the re-sults of the first run. The NSRL is capable of making use of heavy ions in the range of 0.05 to 3 GeV/n slow extracted from BNL's AGS Booster. Many modes of operation were explored during the first run, demonstrating all the capabil-ities designed into the system. Heavy ion intensities from 100 particles per pulse up to 12 × 10 9 particles per pulse were delivered to a large variety of experiments, providing a dose range up to 70 Gy/min over a 5x5 cm 2 area. Re-sults presented will include those related to the production of beams that are highly uniform in both the transverse and longitudinal planes of motion [2].
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K A Ecrown,
L Ahrens,
J M Brennan, J Delong,
C Gardner,
D Gassner,
J W Glenn,
Y Kotlyar,
I Marneris,
A Rusek,
N Tsoupas,
K Zeno
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L Ahrens,
J Alessi,
J Benjamin,
M Blaskiewicz,
J M Brennan,
K A Brown,
C Carlson, J Delong,
T D 'ottavio,
B Frak, [......],
J Morris,
T Roser,
T Satogata,
G Smith,
K S Smith,
D Steski,
N Tsoupas,
P Thieberger,
K Zeno,
S Y Zhang
[show abstract]
[hide abstract]
ABSTRACT: The RHIC 2003 Physics Run [1] required collisions be-tween gold ions and deuterons. The injector necessarily had to deliver adequate quality (transverse and longitudinal emittance) and quantity of both species. For gold this was a continuing evolution from past work [2]. For deuterons it was new territory. For the filling of the RHIC the injector not only had to deliver quality beams but also had to switch between these species quickly. This paper details the col-lider requirements and our success in meeting these. Some details of the configurations employed are given.
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L Ahrens,
J Alessi,
J Benjamin,
M Blaskiewicz,
J M Brennan,
K A Brown,
C Carlson, J Delong,
C J Gardner,
J W Glenn,
T Hayes,
W W Mackay,
G Marr,
J Morris,
T Roser,
F Severino,
K S Smith,
D Steski,
N Tsoupas,
A Zaltsman
