Author: Awida, M.H.
Paper Title Page
WEPPC043 Transverse Kick Analysis of SSR1 Due to Possible Geometrical Variations in Fabrication 2306
 
  • M.H. Awida, P. Berrutti, I.V. Gonin, T.N. Khabiboulline, V.P. Yakovlev
    Fermilab, Batavia, USA
 
  Funding: Operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the U.S. DOE
Due to fabrication tolerance, it is expected that some geometrical variations could happen to the SSR1 cavities of Project X, like small shifts in the transverse direction of the beam pipe or the spoke. It is necessary to evaluate the resultant transverse kick due to these geometrical variations, in order to make sure that they are within the limits of the correctors in the solenoids. In this paper, we report the transverse kick values for various fabrications errors and the sensitivity of the beam to these errors.
 
 
WEPPC044 Multipole Effects Study for Project X Front End Cavities 2309
 
  • P. Berrutti, M.H. Awida, I.V. Gonin, J.-F. Ostiguy, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, USA
 
  Effects of RF field asymmetry along with multipoles have been studied in Project X front end cavities. One family of half wave resonators operating at 162.5 and two of spoke resonators operating at 325 MHz have been analysed. HWR and spoke resonators unlike elliptical cavities, do not have axial symmetry, hence a quadrupole perturbation to the beam is present. The purpose of this paper is to explain the approach and the calculation method used to understand and overcome the drawbacks due to the RF field asymmetry.  
 
WEPPC045 Optimization of the Geometric Beta for the SSR2 Cavities of the Project X 2312
 
  • P. Berrutti, M.H. Awida, I.V. Gonin, N. Solyak, A. Vostrikov, V.P. Yakovlev
    Fermilab, Batavia, USA
 
  Project X based on the 3 GeV CW superconducting Linac and is currently in the R&D phase. The cw SC Linac starts from a low-energy SCRF section (2.1 - 165 MeV) containing three different types of resonators. HWR f=162.5 MHz (2.1 - 11 MeV) having β= 0.11, SSR1 f= 325 MHz (11 - 35 MeV) having β = 0.21. In this paper we present the analysis that lead to the final design of SSR2 f=325 MHz cavity (35 - 165 MeV). We present the results of optimization of the geometric beta and the comparison between single, double and triple spoke resonators used in Project X frontend.  
 
WEPPC047 Effects of the RF Field Asymmetry in SC Cavities of the Project X 2318
 
  • I.V. Gonin, M.H. Awida, P. Berrutti, A. Saini, B.G. Shteynas, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, USA
  • P.N. Ostroumov
    ANL, Argonne, USA
 
  The low-energy SCRF section of CW SC linac of Project X starts from Half Wave Resonators (HWR) having operating frequency f=162.5 MHz, optimal β= 0.11 and will accelerate the beam from 2 MeV up to 11 MeV. The preliminary analysis of beam dynamics shows that multipole effects caused by asymmetry of RF fields in HWR cavities aren’t negligible. In this paper we present the analysis of influence of multipole effects on beam dynamics and discuss the possible solutions how to compensate these effects.  
 
WEPPC053 SSR1 HOM Analysis and Measurements 2333
 
  • M.H. Awida, P. Berrutti, I.V. Gonin, T.N. Khabiboulline, V.P. Yakovlev
    Fermilab, Batavia, USA
 
  Funding: Operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the U.S. DOE
Single spoke resonators (SSR1, β=0.22) are currently under development for Project X at Fermilab. In this paper, extensive Higher Order Mode (HOM) analysis carried out on SSR1 is reported including the simulated R/Q for monopoles, dipoles, and quadrupoles. HOM measurements carried out on several spoke cavities are also reported including the harmonic response and the bead pull measurements. Comparison between the measured R/Q values and the simulated ones are presented.
 
 
WEPPC054 Resonance Excitation of Longitudinal High Order Modes in Project X Linac 2336
 
  • A.I. Sukhanov, M.H. Awida, I.V. Gonin, T.N. Khabiboulline, A. Lunin, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, USA
 
  Results of simulation of power loss due to excitation of longitudinal high order modes (HOMs) in the accelerating superconducting RF system of CW linac of Project X are presented. Beam structures corresponding to the various modes of Project X operation are considered: CW regime for 3 GeV physics program; pulsed mode for neutrino experiments; and pulsed regime, when Project X linac operates as a driver for Neutrino Factory/Muon Collider. Power loss and associated heat load due to resonance excitation of longitudinal HOMs are shown to be small in all modes of operation. Conclusion is made that HOM couplers can be removed from the design of superconducting RF cavities of Project X linac.  
 
WEPPC056 Pressure Sensitivity Characterization of Superconducting Spoke Cavities 2339
 
  • D. Passarelli, M.H. Awida, I.V. Gonin, L. Ristori, V.P. Yakovlev
    Fermilab, Batavia, USA
 
  The following proposal illustrates a method to characterize the pressure sensitivity behavior of superconducting spoke cavities. This methodology relies on evaluating the variation of resonant frequency of a cavity by observing only the displacements at designed regions of the cavity. The proposed method permits a reduced computational burden and a systematic approach to achieve a minimum value of pressure sensitivity in a complex system of dressed cavity. This method has been used to characterize the superconducting spoke cavities typs−1 (SSR1), under development for Project X, and to design the helium containment vessel in such way to reduce the pressure sensitivity value to zero.  
 
WEPPC057 Design of SSR1 Single Spoke Resonators for PXIE 2342
 
  • L. Ristori, M.H. Awida, I.V. Gonin, M. Merio, D. Passarelli, V.P. Yakovlev
    Fermilab, Batavia, USA
 
  Funding: Operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy.
The Project X Injector Experiment (PXIE) at Fermilab contains one cryomodule of Single Spoke Resonators operating at 325 MHz with a geometrical beta of 0.2. Two prototypes have been tested successfully at high gradients in the Fermilab Vertical Test Stand (VTS). We have welded a Stainless Steel helium vessel on the first prototype and tested it in the spoke-dedicated Test Cryostat. With excellent results in hand, an order for ten bare resonators was placed with US industry. A new design for the helium vessel was developed for these resonators with the main goal of reducing the sensitivity of the resonator to variations of the helium pressure to meet the requirements of PXIE. A new tuner was developed despite the good results of the first prototype. The new design was inevitable due to the different behavior of the resonator in the new helium vessel. Other aspects were improved such as the maintainability of the tuner motor and piezoelectric actuators allowing their replacement from access ports on the cryomodule's vacuum vessel.
 
 
WEPPD035 Design Considerations for an MEBT Chopper Absorber of 2.1MeV H at the Project X Injector Experiment at Fermilab 2585
 
  • C.M. Baffes, M.H. Awida, A.Z. Chen, Y.I. Eidelman, V.A. Lebedev, L.R. Prost, A.V. Shemyakin, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, USA
 
  Funding: Operated by Fermi Research Alliance, LLC, under Contract No. DE-AC02-07CH11359 with the United States Department of Energy
The Project X Injector Experiment (PXIE) will be a prototype of the Project X front end that will be used to validate the design concept and decrease technical risks. One of the most challenging components of PXIE is the wide-band chopping system of the Medium Energy Beam Transport (MEBT) section, which will form an arbitrary bunch pattern from the initially CW 162.5 MHz 5mA beam. The present scenario assumes diverting 80% of the beam to an absorber to provide a beam with the average current of 1mA to SRF linac. This absorber must withstand a high level of energy deposition and high ion fluence, while being positioned in proximity of the superconductive cavities. This paper discusses design considerations for the absorber, including specific challenges as spreading of energy deposition, management of temperatures and temperature-induced mechanical stresses, radiation effects, surface effects (sputtering and blistering), and maintaining vacuum quality. Thermal and mechanical analyses of a conceptual design are presented, and future plans for the fabrication and testing of a prototype are described.
 
 
WEPPD058 The Project-X 3 GeV Beam Distribution System 2651
 
  • D.E. Johnson, M.H. Awida, M.S. Champion, I.V. Gonin, A.L. Klebaner, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, USA
 
  In the Project X facility, a 3 GeV H CW beam is delivered to three users simultaneously. This will be accomplished by selectively filling appropriate RF buckets at the front end of the linac and then utilizing a RF splitter to transversely separate bunches to three different target halls. A compact TE113 squashed-wall superconducting RF cavity has been proposed to produce the initial vertical deflection. The transport line optics, cavity design parameters, and cryogenic system requirements will be presented.  
 
THPPC030 Multi-physics Analysis of the Fermilab Booster RF Cavity 3347
 
  • M.H. Awida, M.S. Champion, T.N. Khabiboulline, V.A. Lebedev, J. Reid, V.P. Yakovlev
    Fermilab, Batavia, USA
 
  Funding: Operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the U.S. DOE
After about 40 years of operation the RF accelerating cavities in Fermilab Booster need an upgrade to improve their reliability and to increase the repetition rate in order to support a future experimental program. An increase in the repetition rate from 7 to 15 Hz entails increasing the power dissipation in the RF cavities, their ferrite loaded tuners, and HOM dampers. The increased duty factor requires careful modelling for the RF heating effects in the cavity. A multi-physic analysis investigating both the RF and thermal properties of Booster cavity under various operating conditions is presented in this paper.
 
 
THPPP063 CW Room Temperature Re-buncher for the Project X Front End 3880
 
  • G.V. Romanov, M.H. Awida, M. Chen, I.V. Gonin, S. Kazakov, R.A. Kostin, V.A. Lebedev, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, USA
 
  At Fermilab there is a plan to construct the Project X Injector Experiment (PXIE) facility - a prototype of the front end of the Project X, a multi-MW proton source based on a superconducting linac. The construction and successful operations of this facility will validate the concept for the Project X front end, thereby minimizing the primary technical risk element within the Project. The front end of the linac contains a cw room-temperature MEBT section which comprises an ion source, RFQ, and high-bandwidth bunch selective chopper. The length of the MEBT exceeds 9 m, so three re-bunching cavities are used to support the beam longitudinal dynamics. The paper reports RF design of the re-bunchers along with preliminary beam dynamic and thermal analysis of the cavities.