2011 Particle Accelerator Conference - List of Authors (Choi, J.)

Paper	Title	Page
MOP275	Beam Loss Control for the NSLS-II Storage Ring	624
	S.L. Kramer, J. Choi BNL, Upton, Long Island, New York, USA
	Funding: Work supported by U.S. DOE, Contract No.DE-AC02-98CH10886 The shielding design for the NSLS-II storage ring is designed for the full injected beam losses in two periods of the ring around the injection point, but for the remainder of the ring its shielded for <10% top-off injection beam. This will require a system to insure that beam losses do not exceed these levels for time sufficient to cause excessive radiation exposure outside the shield walls. This beam Loss Control and Monitoring (LCM) system will control the beam losses to the more heavily shielded injection region while monitoring the losses outside this region. To achieve this scrapers are installed in the injection region to intercept beam particles that might be lost outside this region. The scrapers will be thin (< 1Xrad) that will allow low energy electrons to penetrate and the subsequent dipole will separate them from the stored beam. These thin scrapers will reduce the radiation from the scraper compared to thicker scrapers. The dipole will provide significant local shielding for particles that hit inside the gap and a source for the loss monitor system that will measure the amount of beam lost in the injection region. * Beam Loss Monitors for NSLS-II Storage Ring, S.L. Kramer & P. Cameron, these proceedings

THP127	Analysis of NSLS-II Touschek Lifetime	2360
	J. Choi, S.L. Kramer BNL, Upton, Long Island, New York, USA
	Funding: Work supported by DOE contract DE-AC02-98CH10886 As scrapers are adopted for the loss control of NSLS-II storage ring, Touschek lifetime estimations for various cases are required to assure the stable operation. However, to estimate the Touschek lifetime, momentum apertures should be measured all along the ring and, if we want to estimate the lifetime in various situations, it can take extremely long time. Thus, rather than simulating for each case, semi-analytic methods with the interpolations are used for the measurements of the momentum apertures. In this paper, we described the methods and showed the results.

THP134	Lifetime Measurement with Pseudo Moveable Septum in NSLS X-ray Ring	2375
	G.M. Wang, J. Choi, R. Heese, S.L. Kramer, T.V. Shaftan, X. Yang BNL, Upton, Long Island, New York, USA
	Funding: Work supported by U.S. DOE, Contract No.DE-AC02-98CH10886 The National Synchrotron Light Source II (NSLS-II) is a state of the art 3 GeV third generation light source currently under construction at Brookhaven National Laboratory and starts to commission in 2014. The beam injection works with two septa and four fast kicker magnets in an injection section. To improve the injection stability and reproducibility, we plan to implement a slow local bump on top of the fast bump so that the fast kicker strength is reduced. This bump works as a pseudo movable septum. We can also use this ‘movable’ septum to measure the storage ring beam partial lifetime resulting from the septum edge and possibly increasing the lifetime by moving the stored beam orbit away from the edge. We demonstrate the feasibility of this idea, by implementing DC bump in NSLS X-ray ring. We report the results of beam lifetime measurements as a function of the amplitude of this bumped orbit relative to the septum and the idea of a slow bump that could reduce the fast bump magnet strengths.

Paper

Title

Page

Beam Loss Control for the NSLS-II Storage Ring

624

S.L. Kramer, J. Choi
BNL, Upton, Long Island, New York, USA

Funding: Work supported by U.S. DOE, Contract No.DE-AC02-98CH10886
The shielding design for the NSLS-II storage ring is designed for the full injected beam losses in two periods of the ring around the injection point, but for the remainder of the ring its shielded for <10% top-off injection beam. This will require a system to insure that beam losses do not exceed these levels for time sufficient to cause excessive radiation exposure outside the shield walls. This beam Loss Control and Monitoring (LCM) system will control the beam losses to the more heavily shielded injection region while monitoring the losses outside this region. To achieve this scrapers are installed in the injection region to intercept beam particles that might be lost outside this region. The scrapers will be thin (< 1Xrad) that will allow low energy electrons to penetrate and the subsequent dipole will separate them from the stored beam. These thin scrapers will reduce the radiation from the scraper compared to thicker scrapers. The dipole will provide significant local shielding for particles that hit inside the gap and a source for the loss monitor system that will measure the amount of beam lost in the injection region.
* Beam Loss Monitors for NSLS-II Storage Ring, S.L. Kramer & P. Cameron, these proceedings

THP127

Analysis of NSLS-II Touschek Lifetime

2360

J. Choi, S.L. Kramer
BNL, Upton, Long Island, New York, USA

Funding: Work supported by DOE contract DE-AC02-98CH10886
As scrapers are adopted for the loss control of NSLS-II storage ring, Touschek lifetime estimations for various cases are required to assure the stable operation. However, to estimate the Touschek lifetime, momentum apertures should be measured all along the ring and, if we want to estimate the lifetime in various situations, it can take extremely long time. Thus, rather than simulating for each case, semi-analytic methods with the interpolations are used for the measurements of the momentum apertures. In this paper, we described the methods and showed the results.

THP134

Lifetime Measurement with Pseudo Moveable Septum in NSLS X-ray Ring

2375

G.M. Wang, J. Choi, R. Heese, S.L. Kramer, T.V. Shaftan, X. Yang
BNL, Upton, Long Island, New York, USA

Funding: Work supported by U.S. DOE, Contract No.DE-AC02-98CH10886
The National Synchrotron Light Source II (NSLS-II) is a state of the art 3 GeV third generation light source currently under construction at Brookhaven National Laboratory and starts to commission in 2014. The beam injection works with two septa and four fast kicker magnets in an injection section. To improve the injection stability and reproducibility, we plan to implement a slow local bump on top of the fast bump so that the fast kicker strength is reduced. This bump works as a pseudo movable septum. We can also use this ‘movable’ septum to measure the storage ring beam partial lifetime resulting from the septum edge and possibly increasing the lifetime by moving the stored beam orbit away from the edge. We demonstrate the feasibility of this idea, by implementing DC bump in NSLS X-ray ring. We report the results of beam lifetime measurements as a function of the amplitude of this bumped orbit relative to the septum and the idea of a slow bump that could reduce the fast bump magnet strengths.