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Title: Chromaticity correction for a muon collider optics

Abstract

Muon Collider (MC) is a promising candidate for the next energy frontier machine. However, in order to obtain peak luminosity in the 10{sup 34} cm{sup 2}s{sup -1} range the collider lattice designmust satisfy a number of stringent requirements. In particular the expected large momentum spread of the muon beam and the very small {beta}* call for a careful correction of the chromatic effects. Here we present a particular solution for the interaction region (IR) optics whose distinctive feature is a three-sextupole local chromatic correction scheme. The scheme may be applied to other future machines where chromatic effects are expected to be large. The expected large muon energy spread requires the optics to be stable over a wide range of momenta whereas the required luminosity calls for {beta}* in the mm range. To avoid luminosity degradation due to hour-glass effect, the bunch length must be comparatively small. To keep the needed RF voltage within feasible limits the momentum compaction factor must be small over the wide range of momenta. A low {beta}* means high sensitivity to alignment and field errors of the Interaction Region (IR) quadrupoles and large chromatic effects which limit the momentum range of optics stability and require strongmore » correction sextupoles, which eventually limit the Dynamic Aperture (DA). Finally, the ring circumference should be as small as possible, luminosity being inversely proportional to the collider length. A promising solution for a 1.5 TeV center of mass energy MC with {beta}* = 1 m in both planes has been proposed. This {beta}* value has been chosen as a compromise between luminosity and feasibility based on the magnet design and energy deposition considerations. The proposed solution for the IR optics together with a new flexible momentum compaction arc cell design allows to satisfy all requirements and is relatively insensitive to the beam-beam effect.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1013749
Report Number(s):
FERMILAB-CONF-11-090-APC
TRN: US1102560
DOE Contract Number:
AC02-07CH11359
Resource Type:
Conference
Resource Relation:
Conference: Presented at 2011 Particle Accelerator Conference (PAC'11), New York, NY, 28 Mar - 1 Apr 2011
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; ACCELERATORS; ALIGNMENT; APERTURES; DESIGN; LUMINOSITY; MAGNETS; MUON BEAMS; MUONS; OPTICS; QUADRUPOLES; SENSITIVITY; STABILITY; Accelerators

Citation Formats

Alexahin, Y., Gianfelice-Wendt, E., Kapin, V., and /Fermilab. Chromaticity correction for a muon collider optics. United States: N. p., 2011. Web.
Alexahin, Y., Gianfelice-Wendt, E., Kapin, V., & /Fermilab. Chromaticity correction for a muon collider optics. United States.
Alexahin, Y., Gianfelice-Wendt, E., Kapin, V., and /Fermilab. Tue . "Chromaticity correction for a muon collider optics". United States. doi:. https://www.osti.gov/servlets/purl/1013749.
@article{osti_1013749,
title = {Chromaticity correction for a muon collider optics},
author = {Alexahin, Y. and Gianfelice-Wendt, E. and Kapin, V. and /Fermilab},
abstractNote = {Muon Collider (MC) is a promising candidate for the next energy frontier machine. However, in order to obtain peak luminosity in the 10{sup 34} cm{sup 2}s{sup -1} range the collider lattice designmust satisfy a number of stringent requirements. In particular the expected large momentum spread of the muon beam and the very small {beta}* call for a careful correction of the chromatic effects. Here we present a particular solution for the interaction region (IR) optics whose distinctive feature is a three-sextupole local chromatic correction scheme. The scheme may be applied to other future machines where chromatic effects are expected to be large. The expected large muon energy spread requires the optics to be stable over a wide range of momenta whereas the required luminosity calls for {beta}* in the mm range. To avoid luminosity degradation due to hour-glass effect, the bunch length must be comparatively small. To keep the needed RF voltage within feasible limits the momentum compaction factor must be small over the wide range of momenta. A low {beta}* means high sensitivity to alignment and field errors of the Interaction Region (IR) quadrupoles and large chromatic effects which limit the momentum range of optics stability and require strong correction sextupoles, which eventually limit the Dynamic Aperture (DA). Finally, the ring circumference should be as small as possible, luminosity being inversely proportional to the collider length. A promising solution for a 1.5 TeV center of mass energy MC with {beta}* = 1 m in both planes has been proposed. This {beta}* value has been chosen as a compromise between luminosity and feasibility based on the magnet design and energy deposition considerations. The proposed solution for the IR optics together with a new flexible momentum compaction arc cell design allows to satisfy all requirements and is relatively insensitive to the beam-beam effect.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Mar 01 00:00:00 EST 2011},
month = {Tue Mar 01 00:00:00 EST 2011}
}

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  • No abstract prepared.
  • The effect of magnet misalignments in the beam orbit and linear optics functions are reviewed and correction schemes are applied to the negative momentum compaction lattice of PS2. Chromaticity correction schemes are also proposed and tested with respect to off-momentum optics properties. The impact of the correction schemes in the dynamic aperture of the lattice is finally evaluated.
  • No abstract prepared.
  • In this paper we present the proposed scheme for reducing the nonlinear chromaticity of the collider in the collision mode. Briefly, the optics of the collider lattice with special emphasis on the interaction regions which are the main sources of chromaticity are discussed. Then, a theoretical calculation of the second-order chromaticity in a storage ring is discussed. Next we focus on the second-order tune shift due to the triplets, the domain sources of chromaticity in the interaction regions. The fifth topic is the theory behind our proposed scheme for correcting higher-order chromaticity. The last concerns of this paper are evaluationmore » of the chromatic performance of the proposed scheme and the effect of the chromaticity-correcting sextupoles on the dynamics aperture. (AIP)« less
  • We address the issue of correcting higher order chromaticities of the collider with one or more low [beta] insertions. The chromaticity contributed by the interaction regions (IRS) depends crucially on the maximum value of [beta] in the two IRs in a cluster, the phase advance between adjacent interaction points (IPs), and the choice of global tune. We propose a correction scheme in which the linear chromaticity is corrected by a global distribution of sextupoles and the second order chromaticity of each IR is corrected by a more local set of sextupoles. Compared to the case where only the linear chromaticitymore » is corrected, this configuration increases the momentum aperture more than three times and also reduces the [beta] beat by this factor. With this scheme, the tune can be chosen to satisfy other constraints and the two IRs in a cluster can be operated independently at different luminosities without affecting the chromatic properties of the ring.« less