1. Work
In January 2007, we installed 5 chambers in a straight Field Free region of PEP-II Low Energy Ring (LER). Closest bend at ~18 meters upstream:
1 stainless steel chamber that allows to measure the Secondary Electron Yield SEY of material exposed to the beam environment
4 TiN/Al chambers of which 2 with Rectangular Grooves and 2 with plain flat surface
Recently in July, we corrected for a misalignment of the chambers (that was leading to previous misleading results..)
Next, some recent results from the groove chamber tests
M. Pivi, SLAC - Sep, 2007
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2. Groove chambers tests
M. Pivi, SLAC - Sep, 2007
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3. Design - Groove Extrusions - SLAC
FAN EVENTUALLY HITS “BOTTOM” OF SLOT FOR FULL SR STRIKE
LIGHT PASSES THRU SLOTS BETW FINS
BECAUSE FAN IS “THICKER” THAN FIN
FIN TIPS= I.D. OF CHAM
FAN HITS HERE FIRST
VIEW IS ROTATED 90 CCW FROM ACTUAL FAN ORIENTATION
Goal: build Rectangular Groove chambers by Al extrusion, TiN coat and install in Straight Section PEP-II LER for tests
p.4
M. Pivi, SLAC - Sep, 2007
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4. Installation in PEP-II LER: Groove chambers
PEP-II LER straight section
e+ 
Connecting Flange
Flat chamber
Groove chamber
Electron detectors
Arc bend B1 magnet upstream
M. Pivi, SLAC - Sep, 2007
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5. After alignment: compare e- current signals
M. Pivi, SLAC - Aug, 2007
electron signal in Groove TiN-chambers « Flat TiN-chambers and Stainless steel chamber.
M. Pivi, SLAC - Sep, 2007
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6. Summary on Groove tests
Rectangular Groove chambers in STRAIGHT sections.
Correct a misalignment of the chambers. July 11, 07.
Successfully measured electron signal in Groove chambers much lower than Flat (no-groove) chamber and Stainless Steel chamber
Simulations campaign ongoing to estimate chambers SEY
Rectangular groove chambers are a possible electron cloud mitigation technique for ILC DR STRAIGHT sections.
Simulations show that the electron cloud is an issue for magnetic field regions of the ILC Damping Ring: wigglers, dipoles, quadrupoles.
The characterization of mitigation techniques in MAGNETS is ongoing at various laboratories: CERN, KEK, Cornell and SLAC.
M. Pivi, SLAC - Sep, 2007
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7. Thanks! K. Ohmi, S. Kato, K. Oide, Y. Suetsugu,
To contributors and collaborators:
R. Kirby, L. Wang, F. Le Pimpec, T. Raubenheimer, J. Seeman, U. Wienands, M. Sullivan,
K. Ohmi, S. Kato, K. Oide, Y. Suetsugu,
D. Arnett, G. Collet, R. Kirby, N. Kurita, T. Markiewicz, B. Mckee, M. Morrison, G. Stupakov, N. Phinney, A. Kulikov, F-J Decker (SLAC), M. Palmer, D. Rubin, D. Rice, L. Schachter, J. Codner, E. Tanke, J. Crittenden (Cornell), J. Gao (HIPEP), A. Markovic et al. (Rostock Univ.), M. Zisman, S. De Santis, C. Celata, M. Furman, J.L. Vay, S. De Santis (LBNL), S. Kato, K. Oide, K. Ohmi, Y. Suetsugu (KEK), F. Willeke, R. Wanzenberg (DESY), J.M. Laurent, A. Rossi, E. Benedetto, F. Zimmermann, G. Rumolo, J.M. Jimenez, J-P. Delahaye (CERN), A. Wolski (Cockroft Uniiv.), B. Macek (LANL), C. Vaccarezza, S. Guiducci, R. Cimino, P. Raimondi (Frascati), O. Malyshev et many other colleagues…
August 6, 2007
M. Pivi, SLAC - Sep, 2007
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