| Paper | Title | Page |
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| TPPE045 | Normal-Conducting High Current RF Photoinjector for High Power CW FEL | 2866 |
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| An RF photoinjector capable of producing high average current with low emittance and energy spread is a key enabling technology for high power CW FEL. The design of a 2.5-cell, pi-mode, 700-MHz normal-conducting RF photoinjector cavity with magnetic emittance compensation is completed. With average gradients of 7, 7, and 5 MV/m in its three accelerating cells, the photoinjector will produce a 2.5-MeV electron beam with 3-nC charge per bunch and transverse rms emittance below 7 mm-mrad. Electromagnetic modeling has been used extensively to optimize ridge-loaded tapered waveguides and RF couplers, and led to a new, improved coupler iris design. The results, combined with a thermal and stress analysis, show that the challenging problem of cavity cooling can be successfully solved. Fabrication of a demo 100-mA (at 35 MHz bunch repetition rate) photoinjector is underway. The design is scalable to higher average currents by increasing the electron bunch repetition rate, and provides a path to a MW-class FEL. This paper presents the cavity design and details of RF coupler modeling. | ||
| WPAP033 | State-of-the-Art Electron Guns and Injector Designs for Energy Recovery Linacs (ERL) | 2292 |
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Funding: This work is supported by NAVSEA, NSWC Crane, the Office of Naval Research, the DOD Joint Technology Office and by the U.S. DOE. A key technology issue of ERL devices for high-power free-electron laser (FEL) and 4th generation light sources is the demonstration of reliable, high-brightness, high-power injector operation. Ongoing programs that target up to 1 Ampere injector performance at emittance values consistent with the requirements of these applications are described. We consider that there are three possible approaches that could deliver the required performance. The first is a DC photocathode gun and superconducting RF (SRF) booster cryomodule. Such a 750 MHz device is being integrated and will be tested up to 100 mA at the Thomas Jefferson National Accelerator Facility beginning in 2007. The second approach is a high-current normal-conducting RF photoinjector. A 700 MHz gun will undergo thermal test in 2006 at the Los Alamos National Laboratory, which, if successful, when equipped with a suitable cathode, would be capable of 1 Ampere operation. The last option is an SRF gun. A half-cell 703 MHz SRF gun capable of delivering 1.0 Ampere will be tested to 0.5 Ampere at the Brookhaven National Laboratory in 2006. The fabrication status, schedule and projected performance for each of these state-of-the-art injector programs will be presented. |
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| RPAT040 | Matching BPM Stripline Electrodes to Cables and Electronics | 2607 |
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Funding: This work was supported by SNS through UT-Batelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE. The SNS is a partnership of six national laboratories: Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos, and Oak Ridge. The Spallation Neutron Source (SNS) is an accelerator-based neutron source being built at Oak Ridge National Laboratory. The 805-MHz coupled-cavity linac (CCL) accelerates an H- beam from 86 to 186 MeV, while the 805 MHz superconducting-cavity linac (SCL) accelerates the beam to its final energy of 1 GeV. The SNS beam position monitors (BPMs) which are used to measure both position and phase of the beam relative to the master oscillator, have the dual-planed design with four one-end-shorted stripline electrodes. We argue that the BPMs are optimally broadband matched to the cabling and electronics when the geometrical mean of the sum-mode and quadrupole-mode impedances is equal to the external-line impedance, 50 Ohms. The analytical results, MAFIA and HFSS simulations, wire measurements, and beam measurements that support this statement are presented. |
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| RPPT068 | Pion-Muon Concentrating System for Detectors of Highly Enriched Uranium | 3757 |
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| One of many possible applications of low-energy antiprotons collected in a Penning trap can be a portable muon source. Released antiprotons annihilate on impact with normal matter producing on average about 3 charged pions per antiproton, which in turn decay into muons. Existence of such negative-muon sources of sufficient intensity would bring into play, for example, detectors of highly enriched uranium based on muonic X-rays. We explore options of collecting and focusing pions and resulting muons to enhance the muon flux toward the detector. Simulations with MARS and MAFIA are used to choose the target material and parameters of the magnetic system consisting of a few solenoids. |