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Accelerator Seminars


Accelerator Seminar Committee:
  Chair: Joe Grames / Past Chair: Anne-Marie Valente

    Members: Carlos Hernandez- Garcia, Gianluigi Ciovati, Vasiliy Morozov and
Steve Benson


 Accelerator Seminars will be scheduled weekly on Thursdays from 11:00 a.m. - 12:00 p.m.
If you would like to schedule a seminar, please contact Joe Grames for approval.

 

DATE: Thursday, May 13, 2015

TITLE: DC-SRF Photoinjector at Peking University

SPEAKER: Jiankui Hao, Peking University

TIME: 11:00 a.m.

LOCATION: CEBAF Center, Room F224/225

ABSTRACT: DC-SRF electron injector, which combines a DC Pierce gun and a 3.5-cell 1.3 GHz superconducting cavity in a cryomodule, has been developed at Peking University. Based on the improvements of beam line, LLRF system and 2K cryogenic system, stable operation of the DC-SRF injector has been carried out recently. Electron beams with 3.4 MeV energy and the currents of ~1mA in a macro-pulse mode was obtained. As the first application of this DC-SRF injector, THz radiation produced with a 10 period undulator was detected. As another application, ultrafast electron diffraction (UED) was successfully carried out with DC-SRF injector.

 

DATE: Thursday, May 14, 2015

TITLE: Stability of Ion Polarization in Figure-8 MEIC

SPEAKER: Anatoliy Kondratenko, Science and Technique Laboratory Zaryad

TIME: 11:00 a.m.

LOCATION: CEBAF Center, Room F326/327

ABSTRACT: The figure-8 shaped MEIC ion collider ring is “transparent” to the spin. In such a collider, any polarization orientation repeats every turn, i.e. the particles are in the region of a zero-integer spin resonance. Colliders transparent to the spin provide a unique capability to obtain any polarization direction of any particle species including deuterons using weak solenoids without affecting orbital parameters of the beam. The spin tune induced by the control solenoids must significantly exceed the strength of the zero-integer spin resonance, which contains a coherent part associated with errors in the collider’s magnetic structure and an incoherent part associated with the beam emittances. In a realistic collider lattice, the coherent part of the resonance strength is a few orders of magnitude greater than the incoherent part. We present calculations of the coherent and incoherent parts of the resonance strength in the MEIC ion collider ring for proton and deuteron beams. We analyze the possibility of compensating the coherent part of the resonance strength using static small solenoids, which will allow one to substantially improve the beam’s polarization properties as well as to significantly reduce the fields of the control solenoids. In particular, the spin reversal time of the spin-flipping system of the MEIC ion collider ring will be on the order of 1 ms instead of 1 s.

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