2011 Particle Accelerator Conference - List of Authors (Rider, N.T.)

Paper	Title	Page
MOP304	Development of an X-Ray Beam Size Monitor with Single Pass Measurement Capability for CesrTA	687
	N.T. Rider, J.P. Alexander, M.G. Billing, J. Dobbins, R.E. Meller, M.A. Palmer, D.P. Peterson, C.R. Strohman CLASSE, Ithaca, New York, USA J.W. Flanagan KEK, Ibaraki, Japan
	The CESR Test Accelerator (CesrTA) program targets the study of beam physics issues relevant to linear collider damping rings. This endeavor requires new instrumentation to study the beam dynamics along trains of ultra low emittance bunches. A key element of the program has been the development of an x-ray beam size monitor capable of collecting single pass measurements of individual bunches in a train over thousands of turns. This instrument utilizes custom, high bandwidth amplifiers and digitization hardware to collect signals from a linear InGaAs diode array. The digitizer is synchronized with the CESR timing system and is capable of recording beam size measurements for bunches spaced by as little as 4ns. The x-ray source is a bending magnet with E_c=0.6 keV during 2 GeV CesrTA operations. For these conditions the amplifier dynamic range was optimized to allow measurements with 3x10⁹ to 10¹¹ particles per bunch. Initial testing is complete. Data analysis and examples of key measurements which illustrate the instrument's performance are presented. This device offers unique measurement capabilities applicable to future high energy physics accelerators and light sources.

WEP022	Status of Low Emittance Tuning at CesrTA	1540
	J.P. Shanks, M.G. Billing, R.E. Meller, M.A. Palmer, M.C. Rendina, N.T. Rider, D. L. Rubin, D. Sagan, C.R. Strohman, Y. Yanay CLASSE, Ithaca, New York, USA
	Funding: Work supported by the National Science Foundation and by the US Department of Energy under contract numbers PHY-0734867 and DE-FC02-08ER41538. We report on the status of emittance tuning techniques at the CESR Test Accelerator CesrTA. The CesrTA experimental program requires the capability to operate in a variety of machine lattices with the smallest possible emittance. We have attempted to minimize the turn-around time of our low emittance tuning procedure. We utilize high bandwidth BPM electronics for fast, precision measurements of orbit, betatron phase, transverse coupling, and dispersion. Turn by turn data is used to measure BPM button electrode gains to a under a percent. Gain-corrected coupling data is utilized to determine BPM tilts to 10mrad, allowing for measurement of vertical dispersion at the level of 10mm. Measurement and analysis of the data for characterizing BPM response takes 5 minutes. Beam based measurement of machine functions, data analysis, and implementing corrections in the machine takes another 5 minutes. An x-ray beam size monitor provides a real time check on the effectiveness of the procedure. A typical correction results in an emittance less than 20pm at 2.1GeV in 1-2 iterations. Sub 15pm has been achieved with adjustment of closed coupling/vertical dispersion bumps and betatron tunes.

Paper

Title

Page

Development of an X-Ray Beam Size Monitor with Single Pass Measurement Capability for CesrTA

687

N.T. Rider, J.P. Alexander, M.G. Billing, J. Dobbins, R.E. Meller, M.A. Palmer, D.P. Peterson, C.R. Strohman
CLASSE, Ithaca, New York, USA
J.W. Flanagan
KEK, Ibaraki, Japan

The CESR Test Accelerator (CesrTA) program targets the study of beam physics issues relevant to linear collider damping rings. This endeavor requires new instrumentation to study the beam dynamics along trains of ultra low emittance bunches. A key element of the program has been the development of an x-ray beam size monitor capable of collecting single pass measurements of individual bunches in a train over thousands of turns. This instrument utilizes custom, high bandwidth amplifiers and digitization hardware to collect signals from a linear InGaAs diode array. The digitizer is synchronized with the CESR timing system and is capable of recording beam size measurements for bunches spaced by as little as 4ns. The x-ray source is a bending magnet with E_c=0.6 keV during 2 GeV CesrTA operations. For these conditions the amplifier dynamic range was optimized to allow measurements with 3x10⁹ to 10¹¹ particles per bunch. Initial testing is complete. Data analysis and examples of key measurements which illustrate the instrument's performance are presented. This device offers unique measurement capabilities applicable to future high energy physics accelerators and light sources.

WEP022

Status of Low Emittance Tuning at CesrTA

1540

J.P. Shanks, M.G. Billing, R.E. Meller, M.A. Palmer, M.C. Rendina, N.T. Rider, D. L. Rubin, D. Sagan, C.R. Strohman, Y. Yanay
CLASSE, Ithaca, New York, USA

Funding: Work supported by the National Science Foundation and by the US Department of Energy under contract numbers PHY-0734867 and DE-FC02-08ER41538.
We report on the status of emittance tuning techniques at the CESR Test Accelerator CesrTA. The CesrTA experimental program requires the capability to operate in a variety of machine lattices with the smallest possible emittance. We have attempted to minimize the turn-around time of our low emittance tuning procedure. We utilize high bandwidth BPM electronics for fast, precision measurements of orbit, betatron phase, transverse coupling, and dispersion. Turn by turn data is used to measure BPM button electrode gains to a under a percent. Gain-corrected coupling data is utilized to determine BPM tilts to 10mrad, allowing for measurement of vertical dispersion at the level of 10mm. Measurement and analysis of the data for characterizing BPM response takes 5 minutes. Beam based measurement of machine functions, data analysis, and implementing corrections in the machine takes another 5 minutes. An x-ray beam size monitor provides a real time check on the effectiveness of the procedure. A typical correction results in an emittance less than 20pm at 2.1GeV in 1-2 iterations. Sub 15pm has been achieved with adjustment of closed coupling/vertical dispersion bumps and betatron tunes.