P. Ingrassia | Brookhaven National Laboratory (original) (raw)
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Papers by P. Ingrassia
2007 IEEE Particle Accelerator Conference (PAC), 2007
The Relativistic Heavy Ion Collider (RHIC) as the first high energy polarized proton collider was... more 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.
In three polarized proton runs at the AGS it was recently shown that the imperfection depolarizin... more In three polarized proton runs at the AGS it was recently shown that the imperfection depolarizing resonances in the AGS can be overcome with a 5% partial snake and the intrinsic depolarizing resonances could be jumped with the pulsed tune-jump quadrupoles even in the presence of the partial snake. For the first time polarized proton beam was accelerated up to the required RHIC injection energy of 25 GeV. No polarization was lost due to the imperfection resonances and the depolarization from most intrinsic resonances was avoided with the tune-jump quadrupoles. However, significant amount of polarization was lost at 0+ν{sub y}, 12+ν{sub y} and 36+ν{sub y}, which is believed to be partially due to coupling resonances. A novel energy-jump method and other new schemes to overcome the coupling and intrinsic resonances are discussed.
Proceedings of the 2003 Bipolar/BiCMOS Circuits and Technology Meeting (IEEE Cat. No.03CH37440), 2003
The RHIC 2003 Physics Run [1] required collisions between gold ions and deuterons. The injector n... more The RHIC 2003 Physics Run [1] 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. MP6 MP7 Blue Ring AGS Booster Foil TTB Transport Line ATR Transport Line d Au12+ Au79+ d, Au77+ d, Au79+ d, Au32+ Yellow Ring d Tandems RHIC Figure 1: Acceleration of Deuterons and Gold for RHIC.
Proceedings of the 1997 Particle Accelerator Conference (Cat. No.97CH36167), 1998
In the recent polarized proton runs in the AGS, a 5% partial snake was used successfully to overc... more In the recent polarized proton runs in the AGS, a 5% partial snake was used successfully to overcome the imperfection depolarizing resonances. Polarized proton beam was accelerated up to the required RHIC injection energy of 25 GeV. However, significant amount of polarization was lost at 0+ν y , 12+ν y and 36+ν y , which is believed to be partially due to the coupling resonances. To overcome the coupling resonance, an energy-jump was generated by rapidly changing the beam circumference using the powerful AGS rf system. It clearly demonstrates that the novel energy-jump method can successfully overcome coupling resonances and weak intrinsic resonances. 1460 0-7803-4376-X/98/$10.00
2007 IEEE Particle Accelerator Conference (PAC), 2007
The Relativistic Heavy Ion Collider (RHIC) as the first high energy polarized proton collider was... more 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.
In three polarized proton runs at the AGS it was recently shown that the imperfection depolarizin... more In three polarized proton runs at the AGS it was recently shown that the imperfection depolarizing resonances in the AGS can be overcome with a 5% partial snake and the intrinsic depolarizing resonances could be jumped with the pulsed tune-jump quadrupoles even in the presence of the partial snake. For the first time polarized proton beam was accelerated up to the required RHIC injection energy of 25 GeV. No polarization was lost due to the imperfection resonances and the depolarization from most intrinsic resonances was avoided with the tune-jump quadrupoles. However, significant amount of polarization was lost at 0+ν{sub y}, 12+ν{sub y} and 36+ν{sub y}, which is believed to be partially due to coupling resonances. A novel energy-jump method and other new schemes to overcome the coupling and intrinsic resonances are discussed.
Proceedings of the 2003 Bipolar/BiCMOS Circuits and Technology Meeting (IEEE Cat. No.03CH37440), 2003
The RHIC 2003 Physics Run [1] required collisions between gold ions and deuterons. The injector n... more The RHIC 2003 Physics Run [1] 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. MP6 MP7 Blue Ring AGS Booster Foil TTB Transport Line ATR Transport Line d Au12+ Au79+ d, Au77+ d, Au79+ d, Au32+ Yellow Ring d Tandems RHIC Figure 1: Acceleration of Deuterons and Gold for RHIC.
Proceedings of the 1997 Particle Accelerator Conference (Cat. No.97CH36167), 1998
In the recent polarized proton runs in the AGS, a 5% partial snake was used successfully to overc... more In the recent polarized proton runs in the AGS, a 5% partial snake was used successfully to overcome the imperfection depolarizing resonances. Polarized proton beam was accelerated up to the required RHIC injection energy of 25 GeV. However, significant amount of polarization was lost at 0+ν y , 12+ν y and 36+ν y , which is believed to be partially due to the coupling resonances. To overcome the coupling resonance, an energy-jump was generated by rapidly changing the beam circumference using the powerful AGS rf system. It clearly demonstrates that the novel energy-jump method can successfully overcome coupling resonances and weak intrinsic resonances. 1460 0-7803-4376-X/98/$10.00