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Edwards, H.

Paper Title Page
MOPAS017 Upgrade of the A0 Photoinjector Laser System for NML Accelerator Test Facility at Fermilab 470
 
  • J. Ruan, H. Edwards, R. P. Fliller, J. K. Santucci
    Fermilab, Batavia, Illinois
  
  Funding: Operated by Universities Research Association, Inc. for the U. S. Department of Energy under contract DE-AC02-76CH03000

The current Fermilab A0 Photoinjector laser system includes a seed laser, a flashlamp pumped multipass amplifier cavity, a flashlamp pumped 2-pass amplifier system followed by an IR to UV conversion stage. However the current system can only deliver up to 800 pulses due to the low efficiency of Nd:Glass used inside multi-pass cavity. In this paper we will report the effort to develop a new multi pass cavity based on Nd:YLF crystal end-pumped by diode laser. We will also discuss the foreseen design of the laser system for the NML accelerator test facility at Fermilab.

 
WEPMN092 Capture Cavity II Results at FNAL 2245
 
  • J. Branlard, G. I. Cancelo, R. H. Carcagno, B. Chase, H. Edwards, R. P. Fliller, B. M. Hanna, E. R. Harms, A. Hocker, T. W. Koeth, M. J. Kucera, A. Makulski, U. Mavric, M. McGee, A. H. Paytyan, Y. M. Pischalnikov, P. S. Prieto, R. Rechenmacher, J. Reid, K. R. Treptow, N. G. Wilcer, T. J. Zmuda
    Fermilab, Batavia, Illinois
  
  Funding: FRA

As part of the research and development towards the International Linear Collider (ILC), several test facilities have been developed at Fermilab. This paper presents the latest LLRF results obtained with Capture Cavity II at these test facilities. The main focus will be on controls and RF operations using the SIMCON based LLRF system. Details about hardware upgrades and overall system performance will be also explained. Finally, design considerations and objectives for the future test facility at the New Muon Laboratory (NML) will be presented.

 
WEPMN094 Experience with Capture Cavity II 2251
 
  • T. W. Koeth, J. Branlard, H. Edwards, R. P. Fliller, E. R. Harms, A. Hocker, T. W. Koeth, M. McGee, Y. M. Pischalnikov, P. S. Prieto, J. Reid
    Fermilab, Batavia, Illinois
  
  Funding: This work supported by Universities Research Association Inc. under contract DE-AC02-76CH00300 with the U. S. DOE.

Valuable experience in operating and maintaining superconducting RF cavities in a horizontal test module has been gained with Capture Cavity II. We report on all facets of our experience to date.

 
WEPMN096 Status of the 3.9-GHz Superconducting RF Cavity Technology at Fermilab 2254
 
  • E. R. Harms, T. T. Arkan, L. Bellantoni, H. Carter, H. Edwards, M. Foley, T. N. Khabiboulline, D. V. Mitchell, D. R. Olis, A. M. Rowe, N. Solyak
    Fermilab, Batavia, Illinois
  
  Funding: This work supported by Universities Research Association Inc. under contract DE-AC02-76CH00300 with the U. S. DOE.

Fermilab is involved in an effort to assemble 3.9 GHz superconducting RF cavities into a four cavity cryomodule for use at the DESY TTF/FLASH facility as a third harmonic structure. The design gradient of these cavities is 14 MV/m limited by thermal heat transfer. This effort involves design, fabrication, intermediate testing, assembly, and eventual delivery of the cryomodule. We report on all facets of this enterprise from design through future plans. Included will be test results of single 9-cell cavities, lessons learned, and current status.

 
WEPMN105 Fast Thermometry for Superconducting RF Cavity Testing 2280
 
  • D. F. Orris, L. Bellantoni, R. H. Carcagno, H. Edwards, E. R. Harms, T. N. Khabiboulline, S. Kotelnikov, A. Makulski, R. Nehring, Y. M. Pischalnikov
    Fermilab, Batavia, Illinois
  
  Funding: Work supported by Universities Research Association Inc. under Contract No. DE-AC02-76CH03000 with the United States Department of Energy.

Fast readout of strategically placed low heat capacity thermometry can provide valuable information of Superconducting RF (SRF) cavity performance. Such a system has proven very effective for the development and testing of new cavity designs. Recently, several RTDs were installed in key regions of interest on a new 9 cell 3.9 GHz SRF cavity with integrated HOM design at FNAL. A data acquisition system was developed to read out these sensors with enough time and temperature resolution to measure temperature changes on the cavity due to heat generated from multipacting or quenching within power pulses. The design and performance of this fast thermometry system will be discussed along with results from tests of the 9 cell 3.9GHz SRF cavity.

 
WEPMN108 A Technique for Monitoring Fast Tuner Piezoactuator Preload Forces for Superconducting RF Cavities 2289
 
  • Y. M. Pischalnikov, J. Branlard, R. H. Carcagno, B. Chase, H. Edwards, A. Makulski, M. McGee, R. Nehring, D. F. Orris, V. Poloubotko, C. Sylvester, S. Tariq
    Fermilab, Batavia, Illinois
  
  Funding: Work supported by Universities Research Association Inc. under Contract No. DE-AC02-76CH03000 with the United States Department of Energy.

The technology for mechanically compensating Lorentz Force detuning in superconducting RF cavities has already been developed at DESY. One technique is based on commercial piezoelectric actuators and was successfully demonstrated on TESLA cavities*. Piezo actuators for fast tuners can operate in a frequency range up to several kHz; however, it is very important to maintain a constant preload force on the piezo stack in the range of 10 to 50% of its specified blocking force. Determining the preload force during cooldown, warm-up, or re-tuning of the cavity is difficult without instrumentation, and exceeding the specified range can permanently damage the piezo stack. A technique based on strain gauge technology for superconducting magnets has been applied to fast tuners for monitoring the preload on the piezoelectric assembly. This paper will address the design and testing of piezo actuator preload sensor technology. Results from measurements of preload sensors installed on the tuner of the DESY Capture Cavity II tested at Fermilab will be presented. These results include measurements during cooldown, warm-up, and cavity tuning along with dynamic Lorentz force compensation.

* M. Liepe et al," Dynamic Lorentz Force Compensation with a Fast Piezoelectric Tuner" PAC2001

 
WEPMN111 3.9 GHz Superconducting Accelerating 9-cell Cavity Vertical Test Results 2295
 
  • T. N. Khabiboulline, C. A. Cooper, N. Dhanaraj, H. Edwards, M. Foley, E. R. Harms, D. V. Mitchell, A. M. Rowe, N. Solyak
    Fermilab, Batavia, Illinois
  • W.-D. Moller
    DESY, Hamburg
  
  The 3rd harmonic 3.9GHz accelerating cavity was proposed to improve beam performances of the FLASH (TTF/DESY) facility. In the frame of collaboration Fermilab will provide DESY with a cryomodule containing a string of four cavities. In addition, a second cryomodule with one cavity will be fabricated for installation in the Fermilab photo-injector, which will be upgraded for the ILC accelerator test facility. The first results of vertical tests of 9-cell Nb cavities didn?t reached the designed accelerating gradient. The main problem is multipactoring in HOM couplers, which leads to quenching and overheating of the HOM couplers. New HOM couplers with improved design integarated to next 9-cell cavities. In this paper we present all results of vertical tests.  
THPAS079 A Copper 3.9 GHz TM110 Cavity for Emittance Exchange 3663
 
  • T. W. Koeth
    Rutgers University, The State University of New Jersey, Piscataway, New Jersey
  • L. Bellantoni, D. A. Edwards, H. Edwards, R. P. Fliller
    Fermilab, Batavia, Illinois
  
  Funding: Work supported by Universities Research Association Inc. under contract DE-AC02-76CH00300 with the U. S. DOE.

An experiment is being constructed at Fermilab's A0 Photoinjector to exchange longitudinal and transverse beam emittances. The exchange is preformed by an optics channel consisting of two dogleg bend sections with a transverse deflecting mode cavity between them. In this paper we discuss the construction of the TM110 Mode Cavity. The cavity, based on a superconducting design will be constructed of copper. In addition, the cavity will be cooled with liquid nitrogen to fit within power and mode spacing requirements. The TM110 cavity operating requirements are presented as will the detail of the design, construction, tuning, and commissioning of the TM110 cavity.

 
THPAS094 Transverse to Longitudinal Emittance Exchange Beamline at the A0 Photoinjector 3702
 
  • R. P. Fliller
    BNL, Upton, Long Island, New York
  • D. A. Edwards, H. Edwards
    Fermilab, Batavia, Illinois
  • K. C. Harkay, K.-J. Kim
    ANL, Argonne, Illinois
  • T. W. Koeth
    Rutgers University, The State University of New Jersey, Piscataway, New Jersey
  
  Funding: Work supported by Universities Research Association Inc. under contract DE-AC02-76CH00300 with the U. S. DOE.

The A0 photoinjector is being reconfigured to test the principal of transverse to longitudinal emittance exchange as proposed by Emma et. al., Kim and Sessler, and others. The ability to perform such an exchange could have major advantages to FELs by reducing the transverse emittance. Several schemes to carry out the exchange are possible and will be reported separately. At the Fermilab A0 Photoinjector we are constructing a beamline to demonstrate this transverse to longitudinal emittance exchange. This beamline will consist of a dogleg, and a TM110 5 cell copper cavity followed by another dogleg. The beamline is designed to reuse the bunch compressor dipoles of the photoinjector, along with some existing diagnostics. Beamline layout and optics discussed along with inital data. Future possibilites of performing a similar experiment at the proposed NML facility at Fermilab are also discussed.

 
FRPMN062 OTR Interferometry Diagnostic for the A0 Photoinjector 4144
 
  • G. M. Kazakevich
    BINP SB RAS, Novosibirsk
  • H. Edwards, R. P. Fliller, V. A. Lebedev, S. Nagaitsev, R. Thurman-Keup
    Fermilab, Batavia, Illinois
  
  Funding: Operated by Universities Research Association, Inc. for the U. S. Department of Energy under contract DE-AC02-76CH03000.

OTR interferometry (OTRI) is an attractive diagnostic for investigation of relativistic electron beam parameters. The diagnostic is currently under development at the A0 Photoinjector. This diagnostic is applicable for NML accelerator test facility that will be built at Fermilab. The experimental setups of the OTR interferometers for the Photoinjector prototype are described in the report. Results of simulations and measurements are presented and discussed.

 
FRPMS011 Design of an Electro-Optical Sampling Experiment at the AWA Facility 3901
 
  • J. Ruan, H. Edwards, V. E. Scarpine, C.-Y. Tan, R. Thurman-Keup
    Fermilab, Batavia, Illinois
  • YL. Li, J. G. Power
    ANL, Argonne, Illinois
  • T. J. Maxwell
    Northern Illinois University, DeKalb, Illinois
  
  Funding: Supported by US DOE

The free space electro-optical (EO) sampling technique is a powerful tool for analyzing the longitudinal charge density of an ultrashort e-beam. In this paper, we present

  1. experimental results for a laser-based mock-up of the EO experiment* and
  2. a design for a beam-based, single-shot, EO sampling experiment using the e-beam from the Argonne Wakefield Accelerator (AWA) RF photoinjector.
For the mock-up, a tabletop terahertz experiment is conducted in the AWA laser room. The mock-up uses an IR beam incident on <110> ZnTe crystal to produce a THz pulse via optical rectification. Detection is based on the cross correlation between the THz field and the probe IR laser field in a second <110> ZnTe crystal. Potential application of this technique to the ILC accelerator test facility at Fermilab is also presented.

* Yuelin Li, Appl. Phys. Lett. 88, 251108, 2006