| Paper | Title | Page |
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| WEPMN093 | Multipactor Simulations in Superconducting Cavities | 2248 |
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| The multipactor (MP) is a well-known phenomenon. The existence of resonant trajectories can lead to electron avalanche under certain field level and surface conditions. In this paper we describe features of the extension of Analyst software - PT3P code developed for MP simulations in a real 3D RF structures, such as cavities, couplers, RF windows etc. Also we present the results of MP simulations in HOM couplers of TESLA, SNS β=0.61 and β=0.81 and FNAL 3-rd harmonic cavities. We discuss the comparison of simulations with experimental results. | ||
| WEPMN098 | New HOM Coupler Design for 3.9 GHz Superconducting Cavities at FNAL | 2259 |
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| Last few years Fermilab is developing the superconducting third harmonic section for the FLASH (TTF/DESY) upgrade. The results of vertical tests of 9-cell Nb cavities didn't reached the designed accelerating gradient. The main gradient limitation is multipacting in HOM coupler. In this paper we present the results of vertical tests accompanied with 3D Analyst simulations of multipacting. Also we discuss the RF design of a new HOM couplers. The goal of a new design is to eliminate multipacting and to increase the frequency of second resonance of the HOM. Increasing the frequency will decrease the electric and magnetic fields having the goal to decrease the thermal load on antenna. | ||
| WEPMN099 | Production of 325 MHz Single Spoke Resonators at FNAL | 2262 |
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Funding: US Department of Energy
The High Intensity Neutrino Source (HINS) project represents the current effort at Fermi National Accelerator Laboratory to produce an 8-GeV proton linac based on about 400 independently phased superconducting resonators. Eighteen β=0.21 single spoke resonators, operating at 325 MHz, comprise the first stage of the linac cold section. We are presenting the production status of the first two of these resonators and the performance of the tuning mechanism prototype. In particular, we will report on the construction phases, the pre-weld tuning process and the comparison of low power RF measurements with calculations made using Microwave Studio*.
* CST MICROWAVE STUDIO (CST MWS), http://www.cst.com/ |
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| WEPMN110 | Fabrication and Test of the First Normal-Conducting Crossbar H-type Accelerating Cavity at Fermilab for HINS | 2292 |
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Funding: This work was supported by the U. S. Department of Energy under contract number DE-AC02-76CH03000 The proposed High Intensity Neutrino Source at Fermilab is based on an 8 GeV linear proton accelerator which consists of a normal-conducting and a superconducting section. The normal-conducting (warm) section is composed of an ion source, a radio frequency quadrupole, a medium energy beam transport and 16 normal-conducting crossbar H-type cavities that accelerate the beam from 2.5 MeV to 10 MeV (from β=0.0744 to β=0.1422). These warm cavities are separated by superconducting solenoids enclosed in individual cryostats. Beyond 10 MeV, the design uses superconducting spoke resonators to accelerate the beam up to 8 GeV. In this paper, we illustrate the completion of the first normal-conducting crossbar h-type cavity (β=0.0744) explaining in detail the mechanical engineering aspects related to the machining and brazing processes. The radio-frequency measurements and tuning performed at Fermilab on the resonator and the comparisons with the former simulations are also discussed. |