GROOVE CHAMBERS EXPERIMENT

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SLAC test chambers installation
GROOVE CHAMBERS EXPERIMENT
SEY TEST STATION
SEY stainless steel chamber Station can be used
to expose samples to PEP-II beam environment and
then measure the Secondary Electron Yield (SEY)
in lab setup (transport in Ultra-High Vacuum
load-lock) Grooved (or Fin) and Flat chambers
installed to measure performance in PEP-II beam
environment
M. Pivi, SLAC - Sep, 2007
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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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Groove chambers tests
M. Pivi, SLAC - Sep, 2007
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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
M. Pivi, SLAC - Sep, 2007
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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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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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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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Thanks! 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