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Title: A Wedge Absorber Experiment at MICE

Abstract

Emittance exchange mediated by wedge absorbers is required for longitudinal ionization cooling and for final transverse emittance minimization for a muon collider. A wedge absorber within the MICE beam line could serve as a demonstration of the type of emittance exchange needed for 6-D cooling, including the configurations needed for muon colliders, as well as configurations for low-energy muon sources. Parameters for this test are explored in simulation and possible experimental configurations with simulated results are presented.

Authors:
 [1];  [2];  [3];  [2];  [4]
  1. Fermilab
  2. IIT, Chicago
  3. Rutherford
  4. Mississippi U.
Publication Date:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
OSTI Identifier:
1412512
Report Number(s):
IPAC-2017-WEPAB133; FERMILAB-CONF-17-148-AD-APC
1626391
DOE Contract Number:
AC02-07CH11359
Resource Type:
Conference
Resource Relation:
Conference: 8th International Particle Accelerator Conference, Copenhagen, Denmark, 05/14-05/19/2017
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS

Citation Formats

Neuffer, David, Mohayai, Tanaz, Rogers, Chris, Snopok, Pavel, and Summers, Don. A Wedge Absorber Experiment at MICE. United States: N. p., 2017. Web. doi:10.18429/JACoW-IPAC2017-WEPAB133.
Neuffer, David, Mohayai, Tanaz, Rogers, Chris, Snopok, Pavel, & Summers, Don. A Wedge Absorber Experiment at MICE. United States. doi:10.18429/JACoW-IPAC2017-WEPAB133.
Neuffer, David, Mohayai, Tanaz, Rogers, Chris, Snopok, Pavel, and Summers, Don. 2017. "A Wedge Absorber Experiment at MICE". United States. doi:10.18429/JACoW-IPAC2017-WEPAB133. https://www.osti.gov/servlets/purl/1412512.
@article{osti_1412512,
title = {A Wedge Absorber Experiment at MICE},
author = {Neuffer, David and Mohayai, Tanaz and Rogers, Chris and Snopok, Pavel and Summers, Don},
abstractNote = {Emittance exchange mediated by wedge absorbers is required for longitudinal ionization cooling and for final transverse emittance minimization for a muon collider. A wedge absorber within the MICE beam line could serve as a demonstration of the type of emittance exchange needed for 6-D cooling, including the configurations needed for muon colliders, as well as configurations for low-energy muon sources. Parameters for this test are explored in simulation and possible experimental configurations with simulated results are presented.},
doi = {10.18429/JACoW-IPAC2017-WEPAB133},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2017,
month = 5
}

Conference:
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  • In the Muon Ionization Cooling Experiment (MICE), muons are cooled by passing through material, then through RF cavities to compensate for the energy loss; which reduces the transverse emittance. It is planned to demonstrate longitudinal emittance reduction via emittance exchange in MICE by using a solid wedge absorber in Step IV. Based on the outcome of previous studies, the shape and material of the wedge were chosen. We address here further simulation efforts for the absorber of choice as well as engineering considerations in connection with the absorber support design.
  • In the Muon Ionisation Cooling Experiment (MICE), muons are cooled by ionisation cooling. Muons are passed through material, reducing the total momentum of the beam. This results in a decrease in transverse emittance and a slight increase in longitudinal emittance, but overall reduction of 6d beam emittance. In emittance exchange, a dispersive beam is passed through wedge-shaped absorbers. Muons with higher energy pass through more material, resulting in a reduction in longitudinal emittance as well as transverse emittance. We consider the cooling performance of different wedge materials and geometries and propose a set of measurements that would be made inmore » MICE.We outline the resources these measurements would require and detail some constraints that guide the choice of wedge parameters.« less
  • This report describes the design issues that are associated with a superconducting focusing solenoid that goes around a liquid hydrogen absorber for the Muon Ionization Cooling Experiment (MICE) proposed for the Rutherford Appleton Laboratory. The solenoid consists of two superconducting coils that may operated at the same polarity or at opposite polarities. As a result, the coils and their support structure must be designed to carry a 360-ton inter-coil force that is forcing the coils apart along their axis. The basic design parameters for the focusing magnet are discussed. The magnet and its cryostat are designed so that the absorbermore » can be assembled and tested before installation into the pre-tested focusing solenoid. Safety requirements for MICE dictate that the insulating vacuum for the superconducting magnet be separated from the insulating vacuum for the absorber and that both vacuum be separated from the experiment vacuum and the vacuum within adjacent RF cavities. The safety issues associated with the arrangement of the various vacuums in the MICE focusing modules are presented. The effect of magnet operation and magnet quench on the liquid hydrogen absorber is also discussed.« less
  • Emittance exchange mediated by wedge absorbers is required for longitudinal ionization cooling and for final transverse emittance minimization for a muon collider. A wedge absorber within the MICE beam line could serve as a demonstration of the type of emittance exchange needed for 6-D cooling, including the configurations needed for muon colliders. Parameters for this test are explored in simulation and possible experimental configurations with simulated results are presented.
  • Pretest 3-D finite element creep calculations of the WIPP wedge pillar experiment have been performed. The calculation shows that the horizontal closure of the drifts on either side of the wedge pillar increase with distance from the tip of the wedge. Vertical closure is greatest at the tip of the wedge and smaller, though not significantly smaller, at the opposite end. The relative shift of the drift walls parallel to the drift axis is greatest at the wedge pillar tip and drops off rapidly with distance along the pillar. At distances of approximately one drift width the parallel shift ismore » small enough that the configuration could be analyzed with a 2-D plane strain model. The results of 2-D plane strain calculations at one station of the 3-D model compare very well with 3-D results (deviations less than or equal to1%). Maximum horizontal closures along the wedge pillar are approximately twice those calculated from a 2-D plane strain single drift model of Morgan and Stone, 1985 that includes stratigraphy. Maximum vertical closures are approximately 1.5 times those obtained from the single drift model. Stresses calculated assuming instantaneous drift creation on both sides of the pillar indicate that wedge pillar failure can be expected at the wedge pillar tip. The distance the failure will propagate is difficult to quantify since the material models did not include a failure criterion. Also the stresses predicted are probably higher than what could be expected with a realistic simulation of the mining sequence.« less