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Title: A Study of Emittance Measurement at the ILC

Abstract

The measurement of the International Linear Collider (ILC) emittance in the ILC beam delivery system (BDS) is simulated. Estimates of statistical and machine-related errors are discussed and the implications for related diagnostics R&D are inferred. A simulation of the extraction of the laser-wire Compton signal is also presented.

Authors:
; ; ; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Stanford Linear Accelerator Center (SLAC)
Sponsoring Org.:
USDOE
OSTI Identifier:
902490
Report Number(s):
SLAC-PUB-12473
TRN: US0702852
DOE Contract Number:
AC02-76SF00515
Resource Type:
Conference
Resource Relation:
Conference: Prepared for European Particle Accelerator Conference (EPAC 06), Edinburgh, Scotland, 26-30 Jun 2006
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; ACCELERATORS; LINEAR COLLIDERS; SIMULATION; Accelerators,ACCPHY

Citation Formats

Blair, G.A., Agapov, I.V., Carter, J., Deacon, L., /Royal Holloway, U. of London, Angal-Kalinin, D.A.K., /Daresbury, Jenner, L.J., /Cockcroft Inst. Accel. Sci. Tech., Ross, M.C., Seryi, A., Woodley, M., and /SLAC. A Study of Emittance Measurement at the ILC. United States: N. p., 2007. Web.
Blair, G.A., Agapov, I.V., Carter, J., Deacon, L., /Royal Holloway, U. of London, Angal-Kalinin, D.A.K., /Daresbury, Jenner, L.J., /Cockcroft Inst. Accel. Sci. Tech., Ross, M.C., Seryi, A., Woodley, M., & /SLAC. A Study of Emittance Measurement at the ILC. United States.
Blair, G.A., Agapov, I.V., Carter, J., Deacon, L., /Royal Holloway, U. of London, Angal-Kalinin, D.A.K., /Daresbury, Jenner, L.J., /Cockcroft Inst. Accel. Sci. Tech., Ross, M.C., Seryi, A., Woodley, M., and /SLAC. Mon . "A Study of Emittance Measurement at the ILC". United States. doi:. https://www.osti.gov/servlets/purl/902490.
@article{osti_902490,
title = {A Study of Emittance Measurement at the ILC},
author = {Blair, G.A. and Agapov, I.V. and Carter, J. and Deacon, L. and /Royal Holloway, U. of London and Angal-Kalinin, D.A.K. and /Daresbury and Jenner, L.J. and /Cockcroft Inst. Accel. Sci. Tech. and Ross, M.C. and Seryi, A. and Woodley, M. and /SLAC},
abstractNote = {The measurement of the International Linear Collider (ILC) emittance in the ILC beam delivery system (BDS) is simulated. Estimates of statistical and machine-related errors are discussed and the implications for related diagnostics R&D are inferred. A simulation of the extraction of the laser-wire Compton signal is also presented.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Apr 16 00:00:00 EDT 2007},
month = {Mon Apr 16 00:00:00 EDT 2007}
}

Conference:
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  • The progress of multiple bunches of charged particles down the main L-band linacs of the ILC (International Linear Collider) can be disrupted by wakefields. These wakefields correspond to the electromagnetic fields excited in the accelerating cavities and have both long-range and short-range components. The horizontal and vertical modal components of the wakefield will be excited at slightly different frequencies (the dipole mode frequency degeneracy's are split) due to inevitable manufacturing errors. We simulate the progress of the ILC beam down the collider under the influence of these wakefields. In particular, we investigate the consequences on the final emittance dilution ofmore » the beam of coupling of the horizontal to the vertical motion of the beam.« less
  • Polarized electron beams generated by DC guns are routinely available at several accelerators including JLAB, Mainz and SLAC. These guns operate with a cathode bias on the order of -100 kV. To minimize space charge effects, relatively long bunches are generated at the gun and then compressed longitudinally external to the gun just before and during initial acceleration. For linear colliders, this compression is accomplished using a combination of rf bunchers. For the basic design of the International Linear Collider (ILC), a 120 kV DC photocathode gun is used to produce a series of nanosecond bunches that are each compressedmore » by two sub-harmonic bunchers (SHBs) followed by an L-band buncher and capture section. The longitudinal bunching process results in a significantly higher emittance than produced by the gun alone. While high-energy experiments using polarized beams are not generally sensitive to the source emittance, there are several benefits to a lower source emittance including a simpler more efficient injector system and a lower radiation load during transport especially at bends as at the damping ring. For the ILC, the SHBs could be eliminated if the voltage of the gun is raised sufficiently. Simulations using the General Particle Tracer (GPT) package indicate that a cathode bias voltage of {ge}200 kV should allow both SHBs to be operated at 433 or even 650 MHz, while {ge}500 kV would be required to eliminate the SHBs altogether. Simulations can be used to determine the minimum emittance possible if the injector is designed for a given increased voltage. A possible alternative to the DC gun is an rf gun. Emittance compensation, routinely used with rf guns, is discussed for higher-voltage DC guns.« less
  • The main L-band linacs of the ILC accelerate 2820 bunches from a center of mass of 10 GeV to 500 GeV (and in the proposed later upgrade, to 1 TeV). The emittance of the vertical plane is approximately 400 times less than that of the horizontal plane. Provided the vertical and horizontal mode dipole frequencies are degenerate then the motion in each plane is not coupled. However, in reality the frequency degeneracy is split and the eigenmodes are shifted due to inevitable manufacturing errors introduced in fabricating 20,000 cavities. This gives rise to a transverse coupling in the horizontal-vertical motionmore » and can readily lead to a dilution in the emittance in the vertical plane. We investigate means to ameliorate this effect dilution by splitting the horizontal-vertical tune of the lattice.« less
  • No abstract prepared.