Paper |
Title |
Page |
TUPFI059 |
Summary of Dense Hydrogen Gas Filled RF Cavity Tests for Muon Acceleration |
1481 |
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- K. Yonehara, M. Chung, M.R. Jana, M.A. Leonova, A. Moretti, A.V. Tollestrup
Fermilab, Batavia, USA
- B.T. Freemire, P.M. Hanlet, Y. Torun
IIT, Chicago, Illinois, USA
- R.P. Johnson
Muons. Inc., USA
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Dense hydrogen gas filled RF cavity has a great potential to accelerate a large phase space muon beam in a strong magnetic field. The concept of novel RF cavity has been demonstrated by using an intense proton beam at Fermilab. The experimental result was agreed extremely well with the conventional dilute plasma physic. Based on the model, the beam-induced plasma in the gas filled RF cavity could be controlled by adding a small amount of electronegative gas in dense hydrogen gas. Overview of these experiments will be shown in this presentation.
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TUPFI064 |
Beam Induced Plasma Dynamics in a High Pressure Gas-Filled RF Test Cell for use in a Muon Cooling Channel |
1496 |
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- B.T. Freemire, P.M. Hanlet, Y. Torun
IIT, Chicago, Illinois, USA
- M. Chung, M.R. Jana, M.A. Leonova, A. Moretti, T.A. Schwarz, A.V. Tollestrup, K. Yonehara
Fermilab, Batavia, USA
- M.G. Collura
Politecnico di Torino, Torino, Italy
- R.P. Johnson
Muons. Inc., USA
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Filling an RF cavity with a high pressure gas prevents breakdown when the cavity is place in a multi-Tesla external magnetic field. The choice of hydrogen gas provides the additional benefit of cooling a beam of muons. A beam of particles traversing the cavity, be it muons or protons, ionizes the gas, creating an electron-ion plasma which absorbs energy from the cavity. The ionization rate can be calculated from a beam intensity measurement. Energy loss measurements indicate the loading per RF cycle per electron-ion pair range from 10-18 to 10-16 Joules in pure hydrogen, and 10-20 to 10-18 Joules when hydrogen is doped with dry air. The addition of an electronegative gas (oxygen) has been observed to reduce the lifetime of ionization electrons in the cavity to below 1 nanosecond. Additionally, the recombination rate of electrons and hydrogen ions has been measured to be on the order of 10-6 cubic centimeters per second. The recombination mechanism and hydrogen ion species, along with the three-body attachment process of electrons to oxygen, will be discussed.
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WEPFI066 |
The RF System for the MICE Experiment |
2848 |
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- K. Ronald, A.J. Dick, C.G. Whyte
USTRAT/SUPA, Glasgow, United Kingdom
- P.A. Corlett
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
- A.J. DeMello, D. Li, S.P. Virostek
LBNL, Berkeley, California, USA
- A.F. Grant, A.J. Moss, C.J. White
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
- P.M. Hanlet
IIT, Chicago, Illinois, USA
- C. Hunt, K.R. Long, J. Pasternak
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
- T.H. Luo, D.J. Summers
UMiss, University, Mississippi, USA
- A. Moretti, R.J. Pasquinelli, D.W. Peterson, R.P. Schultz, J.T. Volk
Fermilab, Batavia, USA
- P.J. Smith
Sheffield University, Sheffield, United Kingdom
- T. Stanley
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
- Y. Torun
Illinois Institute of Technology, Chicago, IL, USA
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The International Muon Ionisation Cooling Experiment (MICE) is designed to demonstrate the effectiveness of ionisation cooling to reduce the phase space footprint of a muon beam, principally to allow the subsequent acceleration of muons for next generation colliders and/or neutrino factories. The experiment (and indeed any subsequent accelerator cooling channel based on the same principles) poses certain unusual requirements on its RF system, whilst the precision measurement of the ionisation cooling process demands special diagnostics. This paper shall outline the key features of the RF system, including the LLRF control, the power amplifier chain, distribution network, cavities, tuners and couplers, all of which must operate in a high magnetic field environment. The RF diagnostics which, in conjunction with the other MICE diagnostics, shall allow detailed knowledge of the amplitude and phase of the acceleration field during the transit of each individual Muon shall also be outlined.
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