PAC2013 - List of Authors (Bai, M.)

Paper

Title

Page

A Graphic Interface for Full Control of the RHIC Optics

472

G. Robert-Demolaize, M. Bai
BNL, Upton, Long Island, New York, USA
X. Shen
Indiana University, Bloomington, Indiana, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
A high level application has been developed for the RHIC collider to provide a complete package for optics control. Optics can be measured using three different algorithms to process turn-by-turn (TBT) beam position monitor (BPM) data from either free (tune meter) or driven (AC dipole) betatron oscillations, and corrected via SVD on a response matrix built around specific sets of quadrupoles. The following reviews the details of those methods, and includes the first results of the operational commissioning of the application.

TUPBA04

AC Dipole Based Optics Measurement and Correction at RHIC

526

X. Shen, S.-Y. Lee
IUCEEM, Bloomington, Indiana, USA
M. Bai, Y. Luo, A. Marusic, G. Robert-Demolaize, S.M. White
BNL, Upton, Long Island, New York, USA
R. Tomás
CERN, Geneva, Switzerland

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Independent component analysis (ICA) was applied to the AC dipole based optics measurement at RHIC to extract beta functions as well as phase advances at each BPM. Existence of excessive beta-beat was observed in both rings of RHIC at store energy. A unique global optics correction scheme was then developed and tested successfully during the RHIC polarized proton run in 2013. The feasibility of using closed orbit bump and sextupole for arc beta-beat correction was also demonstrated. The technique and experimental results of optics correction are reported in this paper.

WETB1

Physics of Polarized Protons in Accelerators

728

M. Bai
BNL, Upton, Long Island, New York, USA

RHIC has reached new record luminosity and proton beam polarizations at the collisions energy of 510 and 200 GeV. Depolarizing effects during acceleration and storage can lead to polarization profiles and therefore reduced average polarization at the collision points. The presentation will introduce the concept of depolarizing resonances and methods to overcome them during beam acceleration, measuring techniques for the proton beam polarization and techniques to maintain the beam polarization during an extended store.

Slides WETB1 [13.289 MB]

WEPBA05

Combining Multiple BPM Measurements for Precession AC Dipole Bump Closure

892

P. Oddo, M. Bai, W.C. Dawson, J. Kewisch, Y. Makdisi, C. Pai, P.H. Pile, T. Roser
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 Energy and RIKEN, Japan.
For the RHIC spin flipper to achieve a rotating field, it requires operating five AC dipoles as a pair of closed orbit bumps. One key requirement is to minimize the remnant AC dipole driven betatron oscillation outside of the spin flipper by 50dB. In the past, due to its inherent sensitivity, a single pickup with a direct-diode detector (3D) and dynamic signal analyzer (DSA) were used to measure bump closure by measuring the remnant oscillations. This however proved to be inadequate, as the betatron phase advance between the AC dipoles is non-zero. A method of combining multiple BPMs into a sensitive measure of bump closure has been developed and will be tested during RHIC polarized proton operation in 2013. This technique as well as the experimental results will be presented.

Paper	Title	Page
TUPAC12	A Graphic Interface for Full Control of the RHIC Optics	472
	G. Robert-Demolaize, M. Bai BNL, Upton, Long Island, New York, USA X. Shen Indiana University, Bloomington, Indiana, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. A high level application has been developed for the RHIC collider to provide a complete package for optics control. Optics can be measured using three different algorithms to process turn-by-turn (TBT) beam position monitor (BPM) data from either free (tune meter) or driven (AC dipole) betatron oscillations, and corrected via SVD on a response matrix built around specific sets of quadrupoles. The following reviews the details of those methods, and includes the first results of the operational commissioning of the application.

TUPBA04	AC Dipole Based Optics Measurement and Correction at RHIC	526
	X. Shen, S.-Y. Lee IUCEEM, Bloomington, Indiana, USA M. Bai, Y. Luo, A. Marusic, G. Robert-Demolaize, S.M. White BNL, Upton, Long Island, New York, USA R. Tomás CERN, Geneva, Switzerland
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Independent component analysis (ICA) was applied to the AC dipole based optics measurement at RHIC to extract beta functions as well as phase advances at each BPM. Existence of excessive beta-beat was observed in both rings of RHIC at store energy. A unique global optics correction scheme was then developed and tested successfully during the RHIC polarized proton run in 2013. The feasibility of using closed orbit bump and sextupole for arc beta-beat correction was also demonstrated. The technique and experimental results of optics correction are reported in this paper.

WETB1	Physics of Polarized Protons in Accelerators	728
	M. Bai BNL, Upton, Long Island, New York, USA
	RHIC has reached new record luminosity and proton beam polarizations at the collisions energy of 510 and 200 GeV. Depolarizing effects during acceleration and storage can lead to polarization profiles and therefore reduced average polarization at the collision points. The presentation will introduce the concept of depolarizing resonances and methods to overcome them during beam acceleration, measuring techniques for the proton beam polarization and techniques to maintain the beam polarization during an extended store.
	Slides WETB1 [13.289 MB]

WEPBA05	Combining Multiple BPM Measurements for Precession AC Dipole Bump Closure	892
	P. Oddo, M. Bai, W.C. Dawson, J. Kewisch, Y. Makdisi, C. Pai, P.H. Pile, T. Roser 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 Energy and RIKEN, Japan. For the RHIC spin flipper to achieve a rotating field, it requires operating five AC dipoles as a pair of closed orbit bumps. One key requirement is to minimize the remnant AC dipole driven betatron oscillation outside of the spin flipper by 50dB. In the past, due to its inherent sensitivity, a single pickup with a direct-diode detector (3D) and dynamic signal analyzer (DSA) were used to measure bump closure by measuring the remnant oscillations. This however proved to be inadequate, as the betatron phase advance between the AC dipoles is non-zero. A method of combining multiple BPMs into a sensitive measure of bump closure has been developed and will be tested during RHIC polarized proton operation in 2013. This technique as well as the experimental results will be presented.