| Paper |
Title |
Page |
| MOPC083 |
Flat Long Pulse Train Formation Using Multi-pass Structure
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250 |
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- J. Ruan, H. T. Edwards, R. P. Fliller
Fermilab, Batavia, Illinois
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Flat long pulse train is part of the requirements for International Linear collider. Here in Fermilab the construction of ILCTA at New Meon Lab will present the similar requirements (3MHz, 2810 Pulses, 5Hz) for the laser systems. In this paper we will report the effort to develop a new multi pass (MP) cavity based on Nd:YLF crystal end-pumped by diode laser. It takes a seed (1054 nm, 4-5ps) from a commercial laser and has a gain of 1000 or more. So far we already tested up to 1000 pulses with 1μs spacing and the pulse train amplitude fluctuation is less than 5% throughout the whole duration. We attribute this to the high optical to optical conversion efficiency achieved using Nd:YLF crystal inside the multi-pass structure. Test with 3MHz spacing train is also discussed and the integration of the new MP cavity into the current laser system is planned.
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| TUPC047 |
Optical Transition Radiation Interferometry for the A0 Photoinjector
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1164 |
| |
- G. M. Kazakevich
BINP SB RAS, Novosibirsk
- H. T. Edwards, R. P. Fliller, S. Nagaitsev, J. Ruan, R. Thurman-Keup
Fermilab, Batavia, Illinois
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OTR interferometry (OTRI) is a promising diagnostic technique and was successfully developed and used for investigation of relativistic beams. For mid-energy accelerators the technique is traditionally based on thin polymer films (the first one is transparent for visible light) providing the beam multiple scattering of about 1 mrad or less. The disadvantage of these films is the unacceptable vacuum properties for photoinjectors and accelerators using superconducting cavities. We studied the application of thin mica sheets for OTRI diagnostics at the A0 Photoinjector in comparison with 2.5 μm thick Mylar films. This diagnostic is also applicable for the ILCTA-NML accelerator test facility that is planned at Fermilab. The experimental setups of the OTR interferometer for the A0 Photoinjector are described in the report. Results of simulations and measurements and comparison of the results obtained using Mylar and Mica-based interferometers are presented and discussed.
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| THPC013 |
Start to End Simulations of Transverse to Longitudinal Emittance Exchange at the A0 Photoinjector
|
3002 |
| |
- R. P. Fliller, H. T. Edwards, J. Ruan
Fermilab, Batavia, Illinois
- T. W. Koeth
Rutgers University, The State University of New Jersey, Piscataway, New Jersey
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Various schemes to exchange the transverse and longitudinal emittance have been proposed (Cornacchia and Emma, Kim et.al). One scheme involves a deflecting mode RF cavity between two doglegs to exchange the horizontal and longitudinal emittances. This will produce a complete and uncoupled emittance exchange in the thin cavity limit using first order matrix optics. Various other effects, such as a finite length cavity, can leave the emittances coupled after the exchange and dilute the final emittances. Other effects such as space charge and synchrotron radiation can only be investigated through simulations. An exchange experiment is underway at the A0 Photoinjector at Fermilab. In this paper we present start to end simulations of the experiment using various codes to account for space charge and Coherent Synchrotron Radiation effects. Astra is used to simulate all of the straight sections, including the deflecting mode RF cavity. CSR track simulates the doglegs, and the spectrometer. The results of these simulations are compared with analytical approximations and preliminary data. The effect on the exchange is also discussed.
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| THPC014 |
Investigation of Possible CSR Induced Energy Spread Effects with the A0 Photoinjector Bunch Compressor
|
3005 |
| |
- R. P. Fliller, H. T. Edwards, G. M. Kazakevich, J. Ruan, R. Thurman-Keup
Fermilab, Batavia, Illinois
- T. W. Koeth
Rutgers University, The State University of New Jersey, Piscataway, New Jersey
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The bunch compressor of the A0 Photoinjector at Fermilab was removed this past spring to install a transverse to longitudinal emittance exchange experiment. Prior to its removal questions arose about the possibility of observing the effects of Coherent Synchrotron Radiation on the compressed beam. The energy spread of the beam with and without compression was measured to observe any changes. Various beam charges were used to look for square law effects associated with CSR. No direct observation of CSR was attempted because the design of the vacuum chamber did not allow it. In this paper we report the results of these experiments and comparison with simulations using ASTRA and CSRTrack. The results are compared with analytical approximations. The implications for the ongoing transverse to longitudinal emittance exchange experiment are discussed.
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| THPC020 |
Emittance Exchange at the Fermilab A0 Photoinjector
|
3020 |
| |
- T. W. Koeth
Rutgers University, The State University of New Jersey, Piscataway, New Jersey
- L. Bellantoni, H. T. Edwards, R. P. Fliller, A. H. Lumpkin, J. Ruan
Fermilab, Batavia, Illinois
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A transverse to longitudinal emittance exchange experiment is underway at the A0 Photoinjector at Fermilab. Our scheme employs a TM110 deflecting mode RF cavity between two magnetic doglegs proposed by Kim et. al. The beamline has been installed, characterization of the beamline is complete and data taking has begun. In this paper we report on efforts to date to observe the transverse to longitudinal emittance exchange. Measurements will be compared to analytical predictions and simulations.
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