PAC2013 - List of Authors (Li, Y.)

Paper

Title

Page

A Fast Rotating Wire Scanner for use in High Current Accelerators

385

S.J. Full, N.I. Agladze, A.C. Bartnik, I.V. Bazarov, J. Dobbins, B.M. Dunham, Y. Li, X. Liu, T.P. Moore, J.J. Savino, K.W. Smolenski
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: This work was supported by the financial assistance from the National Science Foundation (Grant No. DMR-0807731).}
We have developed a cost-effective, fast rotating wire scanner for use in accelerators where high beam currents would otherwise melt even carbon wires. This new design uses a simple planetary gear setup to rotate a carbon wire, fixed at one end, through the beam at speeds in excess of 20 m/s. We will present results from bench tests, as well as transverse beam profile measurements taken at Cornell's high-brightness ERL photoinjector, for a beam energy of 4 MeV and currents up to 35 mA.

Slides TUOBA1 [8.870 MB]

WEPBA09

Changes in Electron Cloud Density with Beam Conditioning at CesrTA

904

J.P. Sikora, J.A. Crittenden, D.O. Duggins, Y. Li, X. Liu
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, and the US Department of Energy DE-FC02-08ER41538, DE-SC0006505.
We compare measurements of electron cloud (EC) buildup in uncoated and TiN-coated aluminum vacuum chambers as a function of integrated beam dose up to 1140 amp-hours. The EC density in newly installed bare aluminum chambers increases with beam dose, while the EC density in the TiN-coated chambers decreases with dose under the same beam conditions. Several techniques are used to monitor EC buildup. These include shielded pickups that measure the flux of cloud electrons onto the beampipe wall, and a TE wave resonance technique that measures the EC density within the volume of the beam-pipe. These measurements were made at the Cornell Electron Storage Ring, which has been reconfigured as a test accelerator CesrTA, providing positron and electron beams with energies ranging from 2 GeV to 5 GeV and a variety of bunch train configurations.

FROAA5

Electron Cloud Measurements Using a Shielded Pickup in a Quadrupole at CesrTA

1437

J.P. Sikora, M.G. Billing, J.V. Conway, J.A. Crittenden, J.A. Lanzoni, Y. Li
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, and the US Department of Energy DE-FC02-08ER41538, DE-SC0006505.
We have recently constructed a shielded pickup in a quadrupole magnet for time-resolved detection of electron cloud. Cloud electrons pass into the detector through an array of small holes in the wall of the beam-pipe that shield the collecting electrode from the direct beam signal. There are two collectors, each aligned on a pole face: one near the longitudinal center of the quadrupole, the other in the fringe field. The signals from the collectors are recorded with a digital oscilloscope. We present a summary of the design, construction and commissioning of this device, as well as initial beam measurements. This work was performed at the Cornell Electron Storage Ring which has been reconfigured as a test accelerator (CesrTA) with positron or electron beam energies ranging from 2 GeV to 5 GeV.

Slides FROAA5 [4.262 MB]

Paper	Title	Page
TUOBA1	A Fast Rotating Wire Scanner for use in High Current Accelerators	385
	S.J. Full, N.I. Agladze, A.C. Bartnik, I.V. Bazarov, J. Dobbins, B.M. Dunham, Y. Li, X. Liu, T.P. Moore, J.J. Savino, K.W. Smolenski Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: This work was supported by the financial assistance from the National Science Foundation (Grant No. DMR-0807731).} We have developed a cost-effective, fast rotating wire scanner for use in accelerators where high beam currents would otherwise melt even carbon wires. This new design uses a simple planetary gear setup to rotate a carbon wire, fixed at one end, through the beam at speeds in excess of 20 m/s. We will present results from bench tests, as well as transverse beam profile measurements taken at Cornell's high-brightness ERL photoinjector, for a beam energy of 4 MeV and currents up to 35 mA.
	Slides TUOBA1 [8.870 MB]

WEPBA09	Changes in Electron Cloud Density with Beam Conditioning at CesrTA	904
	J.P. Sikora, J.A. Crittenden, D.O. Duggins, Y. Li, X. Liu Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, and the US Department of Energy DE-FC02-08ER41538, DE-SC0006505. We compare measurements of electron cloud (EC) buildup in uncoated and TiN-coated aluminum vacuum chambers as a function of integrated beam dose up to 1140 amp-hours. The EC density in newly installed bare aluminum chambers increases with beam dose, while the EC density in the TiN-coated chambers decreases with dose under the same beam conditions. Several techniques are used to monitor EC buildup. These include shielded pickups that measure the flux of cloud electrons onto the beampipe wall, and a TE wave resonance technique that measures the EC density within the volume of the beam-pipe. These measurements were made at the Cornell Electron Storage Ring, which has been reconfigured as a test accelerator CesrTA, providing positron and electron beams with energies ranging from 2 GeV to 5 GeV and a variety of bunch train configurations.

FROAA5	Electron Cloud Measurements Using a Shielded Pickup in a Quadrupole at CesrTA	1437
	J.P. Sikora, M.G. Billing, J.V. Conway, J.A. Crittenden, J.A. Lanzoni, Y. Li Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, and the US Department of Energy DE-FC02-08ER41538, DE-SC0006505. We have recently constructed a shielded pickup in a quadrupole magnet for time-resolved detection of electron cloud. Cloud electrons pass into the detector through an array of small holes in the wall of the beam-pipe that shield the collecting electrode from the direct beam signal. There are two collectors, each aligned on a pole face: one near the longitudinal center of the quadrupole, the other in the fringe field. The signals from the collectors are recorded with a digital oscilloscope. We present a summary of the design, construction and commissioning of this device, as well as initial beam measurements. This work was performed at the Cornell Electron Storage Ring which has been reconfigured as a test accelerator (CesrTA) with positron or electron beam energies ranging from 2 GeV to 5 GeV.
	Slides FROAA5 [4.262 MB]