| Paper |
Title |
Page |
| TUPMS089 |
Thermal Emittance Measurement Design for Diamond Secondary Emission
|
1374 |
| |
- Q. Wu, I. Ben-Zvi, A. Burrill, X. Chang, D. Kayran, T. Rao, J. Smedley
BNL, Upton, Long Island, New York
|
|
| |
Thermal emittance is a very important characteristic of cathodes. A lower thermal emittance cathode has a better performance in limiting emittance for transport down the beam line. A diamond amplified photocathode, being a negative electron affinity (NEA) cathode, promises to deliver a very small thermal emittance. A carefully designed method of measuring the emittance of secondary emission from diamond is presented for the first time. Comparison of possible schemes is carried out by simulation, and the most accessible and accurate method and values are chosen. Systematic errors can be controlled within a very small range, and are carefully evaluated. Aberration and limitations of all equipment are taken into account.
|
|
| WEOCC04 |
Recent Progress on the Diamond Amplified Photo-cathode Experiment
|
2044 |
| |
- X. Chang, I. Ben-Zvi, A. Burrill, J. G. Grimes, T. Rao, Z. Segalov, J. Smedley
BNL, Upton, Long Island, New York
- Q. Wu
IUCF, Bloomington, Indiana
|
|
| |
We report recent progress on the Diamond Amplified Photo-cathode (DAP). The use of a pulsed electron gun provides detailed information about the DAP physics. The secondary electron gain has been measured under various electric fields. We have achieved gains of a few hundred in the transmission mode and observed evidence of emission of electrons from the surface. A model based on recombination of electrons and holes during generation well describes the field dependence of the gain. The emittance measurement system for the DAP has been designed, constructed and is ready for use. The capsule design of the DAP is also being studied in parallel.
|
|
|
Slides
|
|
| WEPMS090 |
High Average Current Low Emittance Beam Employing CW Normal Conducting Gun
|
2547 |
| |
- X. Chang, I. Ben-Zvi, J. Kewisch, C. Pai
BNL, Upton, Long Island, New York
|
|
| |
CW normal conducting guns usually do not achieve very high field gradient and waste much RF power at high field gradient compared to superconducting cavities. But they have less trapped modes and wakefields compared to the superconducting cavities due to their low Q. The external bucking coil can also be applied very close to the cathode to improve the beam quality. By using a low frequency gun with a recessed cathode and a carefully designed beam line we can get a high average current and a high quality beam with acceptable RF power loss on the cavity wall. This paper shows that the CW normal conducting gun can be a backup solution for those projects which need high peak and average current, low emittance electron beams such as the Relativistic Heavy Ion Collider (RHIC) e-cooling project and Energy Recovery Linac (ERL) project.
|
|
| TUPMS076 |
Status of R&D Energy Recovery Linac at Brookhaven National Laboratory
|
1347 |
| |
- V. Litvinenko, J. Alduino, D. Beavis, I. Ben-Zvi, M. Blaskiewicz, J. M. Brennan, A. Burrill, R. Calaga, P. Cameron, X. Chang, K. A. Drees, G. Ganetis, D. M. Gassner, J. G. Grimes, H. Hahn, L. R. Hammons, A. Hershcovitch, H.-C. Hseuh, A. K. Jain, D. Kayran, J. Kewisch, R. F. Lambiase, D. L. Lederle, C. Longo, G. J. Mahler, G. T. McIntyre, W. Meng, T. C. Nehring, B. Oerter, C. Pai, D. Pate, D. Phillips, E. Pozdeyev, T. Rao, J. Reich, T. Roser, T. Russo, Z. Segalov, J. Smedley, K. Smith, J. E. Tuozzolo, G. Wang, D. Weiss, N. Williams, Q. Wu, K. Yip, A. Zaltsman
BNL, Upton, Long Island, New York
- H. Bluem, M. D. Cole, A. J. Favale, D. Holmes, J. Rathke, T. Schultheiss, A. M.M. Todd
AES, Princeton, New Jersey
- B. W. Buckley
CLASSE, Ithaca
- G. Citver
Stony Brook University, StonyBrook
- J. R. Delayen, L. W. Funk, H. L. Phillips, J. P. Preble
Jefferson Lab, Newport News, Virginia
|
|
| |
Funding: Work performed under the auspices of the U. S. Department of Energy and partially funded by the US Department of Defence.
In this paper we present status and plans for the 20-MeV R&D energy recovery linac, which is under construction at Collider Accelerator Department at BNL. The facility is based on high current (up to 0.5 A of average current) super-conducting 2.5 MeV RF gun, single-mode super-conducting 5-cell RF linac and about 20-m long return loop with very flexible lattice. The R&D ERL, which is planned for commissioning in 2008, aims to address many outstanding questions relevant for high current, high brightness energy-recovery linacs.
|
|
| WEOCKI03 |
Status of the R&D Towards Electron Cooling of RHIC
|
1938 |
| |
- I. Ben-Zvi, J. Alduino, D. S. Barton, D. Beavis, M. Blaskiewicz, J. M. Brennan, A. Burrill, R. Calaga, P. Cameron, X. Chang, K. A. Drees, A. V. Fedotov, W. Fischer, G. Ganetis, D. M. Gassner, J. G. Grimes, H. Hahn, L. R. Hammons, A. Hershcovitch, H.-C. Hseuh, D. Kayran, J. Kewisch, R. F. Lambiase, D. L. Lederle, V. Litvinenko, C. Longo, W. W. MacKay, G. J. Mahler, G. T. McIntyre, W. Meng, B. Oerter, C. Pai, G. Parzen, D. Pate, D. Phillips, S. R. Plate, E. Pozdeyev, T. Rao, J. Reich, T. Roser, A. G. Ruggiero, T. Russo, C. Schultheiss, Z. Segalov, J. Smedley, K. Smith, T. Tallerico, S. Tepikian, R. Than, R. J. Todd, D. Trbojevic, J. E. Tuozzolo, P. Wanderer, G. Wang, D. Weiss, Q. Wu, K. Yip, A. Zaltsman
BNL, Upton, Long Island, New York
- D. T. Abell, G. I. Bell, D. L. Bruhwiler, R. Busby, J. R. Cary, D. A. Dimitrov, P. Messmer, V. H. Ranjbar, D. S. Smithe, A. V. Sobol, P. Stoltz
Tech-X, Boulder, Colorado
- A. V. Aleksandrov, D. L. Douglas, Y. W. Kang
ORNL, Oak Ridge, Tennessee
- H. Bluem, M. D. Cole, A. J. Favale, D. Holmes, J. Rathke, T. Schultheiss, J. J. Sredniawski, A. M.M. Todd
AES, Princeton, New Jersey
- A. V. Burov, S. Nagaitsev, L. R. Prost
Fermilab, Batavia, Illinois
- Y. S. Derbenev, P. Kneisel, J. Mammosser, H. L. Phillips, J. P. Preble, C. E. Reece, R. A. Rimmer, J. Saunders, M. Stirbet, H. Wang
Jefferson Lab, Newport News, Virginia
- V. V. Parkhomchuk, V. B. Reva
BINP SB RAS, Novosibirsk
- A. O. Sidorin, A. V. Smirnov
JINR, Dubna, Moscow Region
|
|
| |
Funding: Work done under the auspices of the US DOE with support from the US DOD.
The physics interest in a luminosity upgrade of RHIC requires the development of a cooling-frontier facility. Detailed cooling calculations have been made to determine the efficacy of electron cooling of the stored RHIC beams. This has been followed by beam dynamics simulations to establish the feasibility of creating the necessary electron beam. Electron cooling of RHIC at collisions requires electron beam energy up to about 54 MeV at an average current of between 50 to 100 mA and a particularly bright electron beam. The accelerator chosen to generate this electron beam is a superconducting Energy Recovery Linac (ERL) with a superconducting RF gun with a laser-photocathode. An intensive experimental R&D program engages the various elements of the accelerator: Photocathodes of novel design, superconducting RF electron gun of a particularly high current and low emittance, a very high-current ERL cavity and a demonstration ERL using these components.
|
|
|
|
Slides
|
|
| THPMS087 |
Low Emittance Electron Beams for the RHIC Electron Cooler
|
3187 |
| |
- J. Kewisch, X. Chang
BNL, Upton, Long Island, New York
|
|
| |
Funding: Work performed under the United Staes Department of Energy Contract No. DE-AC02-98CH1-886.
An electron cooler, based on an Energy Recovery Linac (ERL) is under development for the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. This will be the first electron cooler operating at high energy with bunched beams. In order to achieve sufficient cooling of the ion beams the electron have to have a charge of 5 nC and a normalized emittance less than 4 mm mrad. This paper presents the progress in optimizing the injector and the emittance improvements from shaping the charge distribution in the bunch.
|
|
| THPMS088 |
Emittance Compensation for Magnetized Beams
|
3190 |
| |
- J. Kewisch, X. Chang
BNL, Upton, Long Island, New York
|
|
| |
Funding: Work performed under the United Staes Department of Energy Contract No. DE-AC02-98CH1-886.
Emittance compensation is a well established technique* for minimizing the emittance of electron beam from a RF photo-cathode gun. Longitudinal slices of a bunch have a small emittance, but due to the longitudinal charge distribution of the bunch and time dependent RF fields they are not focused in the same way, so that the direction of their phase ellipses diverges in phase space and the projected emittance is much larger. Emittance compensation reverses the divergence. At the location where the slopes of the phase ellipses coincides the beam is accelerated, so that the space charge forces are reduced. A recipe for emittance compensation is given in reference**. For magnetized beams (where the angular momentum is non-zero) such emittance compensation is not sufficient because variations in the slice radius lead to variations in the angular speed and therefore to an increase of emittance in the rotating frame. We describe a method and tools for a compensation that includes the beam magnetization.
* L. Serafini, J. B. Rosenzweig, Phys. Rev E 55, 7565, (1997)
** X. Y. Chang, I. Ben-Zvi, J. Kewisch, Phys. Rev ST AB 9, 044201, (2006)
|
|
| THPAS020 |
3D Simulations of Secondary Electron Generation and Transport in a Diamond Amplifier for Photocathodes
|
3555 |
| |
- D. A. Dimitrov, D. L. Bruhwiler, R. Busby, J. R. Cary
Tech-X, Boulder, Colorado
- I. Ben-Zvi, X. Chang, T. Rao, J. Smedley, Q. Wu
BNL, Upton, Long Island, New York
|
|
| |
The Relativistic Heavy Ion Collider (RHIC) contributes fundamental advances to nuclear physics by colliding a wide range of ions. A novel electron cooling section, which is a key component of the proposed luminosity upgrade for RHIC, requires the acceleration of high-charge electron bunches with low emittance and energy spread. A promising candidate for the electron source is the recently developed concept of a high quantum efficiency photoinjector with a diamond amplifier. We have started to implement algorithms, within the VORPAL particle-in-cell framework, for modeling of secondary electron and hole generation, and for charge transport in diamond. The algorithms include elastic and various inelastic scattering processes over a wide range of charge carrier energies. Initial results from the implemented capabilities will be presented and discussed.
The work at Tech-X Corp. is supported by the U. S. Department of Energy under a Phase I SBIR grant.
|
|
| THPAS096 |
Optics of a Two-Pass ERL as an Electron Source for a Non-Magnetized RHIC-II Electron Cooler
|
3708 |
| |
- D. Kayran, I. Ben-Zvi, R. Calaga, X. Chang, J. Kewisch, V. Litvinenko, E. Pozdeyev
BNL, Upton, Long Island, New York
|
|
| |
Funding: Work performed under the auspices of the U. S. Department of Energy contract No DE-AC02-98CH1-886 with support from the US Department of Defense.
Non-magnetized electron cooling of RHIC requires an electron beam energy of 54.3 MeV, electron charge per bunch of 5 nC, normalized rms beam emittance of 4 mm-mrad, and rms energy spread of 3·10-4 *. In this paper we describe a lattice of a two-pass SCRF energy recovery linac (ERL) and results of a PARMELA simulation that provides electron beam parameters satisfying RHIC electron cooling requirements.
* A. Fedotov, Electron Cooling Studies for RHIC II http://www.bnl.gov/cad/ecooling/docs/PDF/Electron_Cooling.pdf
|
|