2011 Particle Accelerator Conference - List of Authors (Bellavia, S.)

Paper	Title	Page
MOP197	RHIC Stochastic Cooling Motion Control	462
	D.M. Gassner, S. Bellavia, J.M. Brennan, L. DeSanto, W. Fu, C.J. Liaw, R.H. Olsen BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Relativistic Heavy Ion Collider (RHIC) beams are subject to Intra-Beam Scattering (IBS) that causes an emittance growth in all three-phase space planes. The only way to increase integrated luminosity is to counteract IBS with cooling during RHIC stores. A stochastic cooling system [1] for this purpose has been developed, it includes moveable pick-ups and kickers in the collider that require precise motion control mechanics, drives and controllers. Since these moving parts can limit the beam path aperture, accuracy and reliability is important. Servo, stepper, and DC motors are used to provide actuation solutions for position control. The choice of motion stage, drive motor type, and controls are based on needs defined by the variety of mechanical specifications, the unique performance requirements, and the special needs required for remote operations in an accelerator environment. In this report we will describe the remote motion control related beam line hardware, position transducers, rack electronics, and software developed for the RHIC stochastic cooling pick-ups and kickers.

TUP057	The Fundamental Power Coupler and Pick-up of the 56 MHz Cavity for RHIC	916
	Q. Wu, S. Bellavia, I. Ben-Zvi, C. Pai BNL, Upton, Long Island, New York, USA
	Funding: This work was supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE. A fundamental power coupler (FPC) is designed to obtain the ability of fast tuning the 56MHz SRF cavity in RHIC. The FPC will be inserted from one of the chemical cleaning ports at the rear end of the cavity with magnetic coupling to the RF field. The size and the location of the FPC are decided based on the required operational external Q of the cavity. The FPC is designed with variable coupling that would cover a range of power levels, and it is thermally isolated from the base temperature of the cavity, which is 4.2K. A 1kW power amplifier will also be used to close an amplitude control feedback loop. In this paper, we discuss the coupling factor of the FPC with the carefully chosen design, as well as the thermal issues.

TUP058	Fundamental Damper Power Calculation of the 56MHz SRF Cavity for RHIC	919
	Q. Wu, S. Bellavia, I. Ben-Zvi, M.C. Grau, G. Miglionico, C. Pai BNL, Upton, Long Island, New York, USA
	Funding: This work was supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE. At each injection and extraction period of RHIC operation, the beam frequency will be sweeping across a wide range, and some of the harmonics will cross the frequency of the 56MHz SRF cavity. To avoid cavity excitation during these periods, a fundamental damper was designed for the quarter-wave resonator to heavily detune the cavity. The power extracted by the fundamental damper should be compliant with the cooling ability of the system at all stages. In this paper, we discussed the power output from the fundamental damper when it is fully extracted, inserted, and during its movement.

Paper

Title

Page

RHIC Stochastic Cooling Motion Control

462

D.M. Gassner, S. Bellavia, J.M. Brennan, L. DeSanto, W. Fu, C.J. Liaw, R.H. Olsen
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Relativistic Heavy Ion Collider (RHIC) beams are subject to Intra-Beam Scattering (IBS) that causes an emittance growth in all three-phase space planes. The only way to increase integrated luminosity is to counteract IBS with cooling during RHIC stores. A stochastic cooling system [1] for this purpose has been developed, it includes moveable pick-ups and kickers in the collider that require precise motion control mechanics, drives and controllers. Since these moving parts can limit the beam path aperture, accuracy and reliability is important. Servo, stepper, and DC motors are used to provide actuation solutions for position control. The choice of motion stage, drive motor type, and controls are based on needs defined by the variety of mechanical specifications, the unique performance requirements, and the special needs required for remote operations in an accelerator environment. In this report we will describe the remote motion control related beam line hardware, position transducers, rack electronics, and software developed for the RHIC stochastic cooling pick-ups and kickers.

TUP057

The Fundamental Power Coupler and Pick-up of the 56 MHz Cavity for RHIC

916

Q. Wu, S. Bellavia, I. Ben-Zvi, C. Pai
BNL, Upton, Long Island, New York, USA

Funding: This work was supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
A fundamental power coupler (FPC) is designed to obtain the ability of fast tuning the 56MHz SRF cavity in RHIC. The FPC will be inserted from one of the chemical cleaning ports at the rear end of the cavity with magnetic coupling to the RF field. The size and the location of the FPC are decided based on the required operational external Q of the cavity. The FPC is designed with variable coupling that would cover a range of power levels, and it is thermally isolated from the base temperature of the cavity, which is 4.2K. A 1kW power amplifier will also be used to close an amplitude control feedback loop. In this paper, we discuss the coupling factor of the FPC with the carefully chosen design, as well as the thermal issues.

TUP058

Fundamental Damper Power Calculation of the 56MHz SRF Cavity for RHIC

919

Q. Wu, S. Bellavia, I. Ben-Zvi, M.C. Grau, G. Miglionico, C. Pai
BNL, Upton, Long Island, New York, USA

Funding: This work was supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
At each injection and extraction period of RHIC operation, the beam frequency will be sweeping across a wide range, and some of the harmonics will cross the frequency of the 56MHz SRF cavity. To avoid cavity excitation during these periods, a fundamental damper was designed for the quarter-wave resonator to heavily detune the cavity. The power extracted by the fundamental damper should be compliant with the cooling ability of the system at all stages. In this paper, we discussed the power output from the fundamental damper when it is fully extracted, inserted, and during its movement.