ANALYSIS OF NSLS-II TOUSCHEK LIFETIME

Conference · Mon Mar 28 00:00:00 EDT 2011

OSTI ID:1012598

Choi, J; Kramer, S L

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, a 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. Having enough Touschek lifetime is important for synchrotron light source for the users to perform experiments with stable beams. In NSLS-II, the scrapers will be installed for the loss control. Especially, the horizontal scrapers will be installed where the dispersions are maximum. Therefore, we need to find the proper scraper gap values which do not reduce the lifetime too much for the stable beam operation. To estimate reliable Touschek lifetime, we should measure the momentum apertures at many positions along the ring. For the rough estimation of the Touschek lifetime, the RF momentum acceptance can be used and for a more detailed estimation, the linear approximation of synchrotron oscillation can be used. However, for the strong focussing synchrotrons, like NSLS-II, the linear approximation is not enough to obtain the reliable momentum apertures, and, in general, particle tracking simulations are used. However, for NSLS-II case, we need to track the particle about 400 turns at each point to make it a full synchrotron oscillation period and to obtain the reliable Touschek lifetime we need measure the momentum apertures at several hundred positions at least. Therefore, it can take quite a long time if we want to have the reasonable resolution for the measurements. Furthermore, at the simulation, if we want to measure the aperture inside a element, we should divide the element and this will make the simulation longer. Here, we developed a systematic method to calculate the momentum aperture using interpolation tables. Once the tables are prepared, the precise momentum aperture can be calculated instantly at arbitrary position for various situations.

• Research Organization: Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source
• Sponsoring Organization: DOE - Office Of Science
• DOE Contract Number: DE-AC02-98CH10886
• OSTI ID: 1012598
• Report Number(s): BNL-94900-2011-CP; 39KC02000; TRN: US1102340
• Resource Relation: Conference: Particle Accelerator Conference 2011; New York, NY; 20110328 through 20110401
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
ACCELERATORS
APERTURES
APPROXIMATIONS
INTERPOLATION
LIFETIME
LIGHT SOURCES
RESOLUTION
SCRAPERS
SIMULATION
STORAGE RINGS
SYNCHROTRON OSCILLATIONS
SYNCHROTRONS
Touschek lifetime estimations for various cases
horizontal scrapers will be installed
national synchrotron light source