Present and Future Effort in ACFA-FFIR group
Contents: Interaction Region, Support Tube, Collimation, BDS Simulation,
Final Focus System, Dump Line, SLEPT Project, Ground Motion, FEATHER, Nanometer BPM,
Laserwire, Polarimetry, Luminosity | IR ISSUES | Talks
| Minutes | Advanced R&D
Comments and suggestions are very welcome. (email@example.com)
- Optimization of IR-layout ( L*, innermost layer of VTX, crossing angle, extraction line, FEATHER, pair monitor ( Tohoku univ., minutes ) and background)
- Physics and detector
- First optimization was completed in 2000; B=2 and 3 Tesla, L*=2m, 4.3m.
- Recent background estimation; talk(pdf, 2.9MB) presented at LCWS04, 19 April,2004, and talk (pdf, 90KB) presented at the 6th ACFA-LC video conference, December 12, 2003, by T. Aso (Toyama National College of Maritime Technology).
- short history
- 2000, ANSYS calculations of the support tube in the JLC detector,
fabrication of support tube prototype was started.
- 2001, sensor,software improvement and measurements of vibration properties.
- 2002, fabrication of the 1/10 model (cantilever with 4 segmentions, flat and taper flanges)
- 2003, plan (test of the 1/10 model, optimization of the CFRP central tube thickness, etc. )
- 2004, plan
- measurement of oscillating amplitude with different phases at both ends,
- manufacturing of 1/10 model with realistic structures
photo:1/10 model ( 80mm outer diameter, 10mm thick, Al tube ),
- stiffness test of the model and study of a vibration isolation system.
- active feedback system at sub-nanometer level.
- Optimization of thickness of central connection tube, which shall be thinnest keeping stability of oscillation properties of the tube.
- Recent progress report can be found here : tube with taper flanges, flat flanges, and loads.
- Frequency response analysis
Possibility of shorter collimation: 1
- calculation of synchrotron radiations by SAD (new implementation in SAD) : 1, 2
- JLC scheme with muon attenuators ( presented at APPI03 by Ohgaki ) : 1
- estimation of muon background by MUCARLO in cooperation with Namito-san, short muon attenuator?
- understanding of TFO (Tail Folding Octupoles) -role quantitatively and optimization of the collimation system
- collimator design
- beam halo
- gas scattering ; brief review, NLC, 1, 2, 3 and Yamamura's master thesis, Tokyo univ., 2004.3 Japanese, pdf,8,4MB
- dark current ; 1, 2, 3, 4, 5, 6, 7
- longitudinal tail, to be collimated at pre-LINAC collimation.
- estimation of beam halo and dark current at LINAC; beam gas scattering, wake field etc; project, 1
- estimation of backgrounds at detectors; results of 1 , 2.
- synchrotron radiations from final doublet and others
- muons (collimators)
- neutrons (dump line) : 1, 2, 3
- pairs (IP), primary in VD and secondary in CDC
- energy loss along the beam line -- radiation loss
New Final Focus with large L*
- New optics interest : 1, 2, 3, 4, 5
- Optimization of L*; L*=3.5m (roadmap) or 4, 5m? (3.5/4.3m, 4.3m, chromaticity;1, 2, 3:ATF2 ) from physics/detector
- Assessment of effects due to errors in strength (Q , SEXT), positions ( Q, SEXT ) and rotations/longitudinal position ( Q , SEXT ) of each magnet at the FF system
- Beam stabilization ; study on feedback method with orbit corrections
- Estimation of momentum acceptance in terms of luminosity and background
Superconducting final doublet (large aperture with 7 mrad crossing)
- design: 1, 2, 3, 4, 5, 6, 7, 8
- Estimation of background at the dump line, specially synchrotron radiations generated by extractede beam in the final Q, by the BDS simulation
Permanent final doublet
- R&D issues
- method of varying the strength ( for Ebeam=45GeV ~ 250GeV) -- rotation of segmentations?
- tolerances of various errors for the design: strength
- recent progress report can be found here (pdf), which was presented at the ISG11, December 16-19, 2003, by T. Mihara (Kyoto university).
Conventional final doublet
- Design for the optics of L*=3.5m or 4.3m
- Design of extraction line : 1, 2, 3, 4, 5, 6, 7, 8, SQ: 9, 10, 11, 12, 13
- Dump design: water dump ( 1 , 2 ) , beamstrahlung photons
- Optimization of optics ( the second IP through the beam dump ); two dumps and single dump
- Design of magnets considering neutron background
- Estimation of neutron background from a single or two dumps for beamstrahlung photons and electron(positron) beam
- Interface to SAD and CAIN for a unified program routine : SLEPT
- Effect of missing quad-movers and BPMs
- Various BNS damping and low &beta optics
- Assessment of Ground motion effect on main linac and BDS ; studies of 1, 2, 3 .
- Manual(PDF,732KB), K.Kubo, K.L.F.Bane, T.O.Raubenheimer and K.A.Thompson, Phase space simulation program for main linacs of future linear colliders, NLC-Note 14, May 1995.
- Correction Strategy ( PDF, 46KB), html(Japanese) ) , K.Yokoya, written in Japanese, 5 March 2003.
- Requirements for movers at LINAC
( JLC site study group : home page (access control) )
- Poster presented at the ITRP meeting (KEK) ; gif, 951KB
- Preliminary results of KEK GM measurements, talk (pdf,52.9MB) presented at the ISG10, June 17-20 2003, by T.Tauchi.
- Measurements; KEK, Konoike-Tsukuba, F-net etc.
- Preliminary Results (PDF, 2.3MB) presented at the ISG video meeting, 8 May, 2003, by T.Tauchi, K.Fujii, T.Matsuda, H.Yamaoka and N.Uchida.
- Uchida's master thesis, Tsukuba univ., 2003.2, Japanese, pdf
- Measurements at TRISTAN ring, KEK
- GM models
Brief review of GM model and talk(PDF, 2.5MB)
Fast feedback system:FEATHER
- Simulation by using CAIN -- evaluation of feedback performance
- Performance with beam blow up for 7 mrad crossing and L*=3.5m
- Design of the fast feedback system (simple, delayed, improved models, etc.)
- Construction of prototype system (Kicker, BPM etc. ) at the ATF extraction line for beam test
- Schedule, 2004-2007
- Link to FONT
Nanometer BPM ; collaboration with SLAC, LLNL and UK groups
Laserwire ; collaboration with UK, DESY and SLAC groups
- Laser Based Beam Diagnostics at the ATF
- Beam profile measurement
- Beam energy distribution measurement at the 2nd IP of the GLC extraction line.
- Upstream Compton polarimetry; before collisions at sources, DR, LINAC etc.
- Downstream Compton polarimetry after collisions at the dump/extraction line.
- Polarimetry; Important role of polarized positron beams for future linear collider, ( full file of pdf and tif ), T. Hirose (Tokyo Metropolitan), presented at LCWS95, proceedings of "Workshop on Physics and Experiments with Linear Colliders (LCWS95)", edited by A, Miyamoto et.al., 8-12 September 1995,Morioka-Appi, Iwate, Japan, World Scientific, p.748-755.
- Physics events; WW scattering
- Depolarization during collisions
- ref 1) Depolarization due to beam-beam interaction in electron-positron Linear Colliders, Kaoru Yokoya, Pisin Chen. SLAC-PUB-4692, Sep 1988
- ref 2) Spin depolarization due to beam-beam interaction in NLC, Kathleen A. Thompson. SLAC-PUB-8716, Jan 2001.
- Luminosity measurement as a function of the center-of-mass energy
- Energy spread before collisions and beamstrahlung effects as well as initial state radiation
- Bhabha scattering; acollinear angle
- Luminosity monitor (forward calorimeter) and active mask: first study results
- Beamstrahlung monitor: studies of 1, 2, 3