ILC: Vertical Test Stand and its Upgrade Plan C'M' Ginsburg for the extended VTS Group C' Brown, R'

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ILC Vertical Test Stand and its Upgrade Plan
C.M. Ginsburg for the extended VTS Group C.
Brown, R. Carcagno, M. Champion, N. Dhanaraj,
C.M. Ginsburg, C. Grenoble, Y. Huang, A. Lunin,
W.-D. Moeller, A. Mukherjee, R. Nehring, B.
Norris, D. Orris, J. Ozelis, T. Peterson, V.
Poloubotko, T. Powers, O. Prokofiev, R. Rabehl,
I. Rakhno, C. Reid, D.A. Sergatskov,
C. Sylvester, M. Wong, C. Worel, A. YuanAll
Fermilab except (TJNAF) and (DESY)
A vertical cavity test facility (VCTF), for CW RF
vertical testing of bare ILC 1.3 GHz
superconducting RF cavities has been built at
Fermilabs Industrial Building 1 in FY06-FY07.
The VCTF is used to measure the performance of
cavities, both as a study of their production and
processing and as an acceptance test prior to
insertion in a cryomodule. One Vertical Test
Stand (VTS) is now operational.
Cryostat

• Vertical Cavity Test Facility (VCTF)
• One Vertical Test Stand (VTS) in Industrial
  Building 1 (IB1)
• Single, bare 1.3 GHz 9-cell Tesla-style cavities
• Measure Q vs. T (Tmin1.5 K)
• Measure Q vs. Eacc at 2 K
• RF design parameter 250 W (CW) max power at
  cavity
• Qgt5x109 and Eacclt35 MV/m
• or generally Pd (1.04 x 10-3) Eacc2/Q
  lt 250 W
• Use existing IB1 cryogenic capacity 125 W at 2 K
• 250 W for short periods without excessive helium
  bath temperature increase
• Magnetically shielded cryostat
• Ambient field in IB1 pit measured consistent with
  Earths field 0.5 G
• External (room-temperature) Amumetal (80 Ni
  alloy) and internal Cryoperm 10 magnetic shield,
  designed to attenuate field to lt0.01 G at cavity
• Radiation shielding to maintain Controlled Area
  status in IB1
• lt 5 mrem in an hour immediately outside the
  shielding
• lt0.25 mrem/hr in normal working areas

vacuum vessel f42
Cryostat design
Radiation shielding
16 ft
He vessel f28
SRF cavity
VTS cryostat top plate

• First high-power single-cell cavity test July 24,
  2007
• Large-grain niobium cavity borrowed from JLab
• Tesla-style shape (straight end tubes)
• Quench at 27 MV/m accompanied by field emission
• Good cavity performance, comparable to
  performance at JLab
• First try at sending an evacuated cavity from
  JLab to Fermilab
• Important for cavity and process qualification

• First 9-cell test September 7, 2007
• AES01 cavity
• Tested at JLab for AES vendor qualification
• Borrowed for VCTF commissioning
• Tesla-style shape, normal endgroup
• Mediocre cavity performance, comparable to
  performance at JLab
• Quench at 16 MV/m, no field emission
• Second try at sending an evacuated cavity from
  JLab to Fermilab
• Important for cavity and process qualification
  needs work

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ILC Vertical Test Stand and its Upgrade Plan
C.M. Ginsburg for the extended VTS Group C.
Brown, R. Carcagno, M. Champion, N. Dhanaraj,
C.M. Ginsburg, C. Grenoble, Y. Huang, A. Lunin,
W.-D. Moeller, A. Mukherjee, R. Nehring, B.
Norris, D. Orris, J. Ozelis, T. Peterson, V.
Poloubotko, T. Powers, O. Prokofiev, R. Rabehl,
I. Rakhno, C. Reid, D.A. Sergatskov,
C. Sylvester, M. Wong, C. Worel, A. YuanAll
Fermilab except (TJNAF) and (DESY)
For FY08, the VCTF capability will be expanded to
accommodate RD diagnostic instrumentation, and
to begin participation in the global GDE/RD task
for cavity performance (S0) tests, both of which
require extending the test facility capability
and increasing cavity throughput.
Black current/under construction Red proposed
upgrade

• Increase cavity test throughput
• Current throughput estimate 48 cavity tests/year
  
• Increase throughput to gt200 cavity tests/year by
  FY10 (dependent on funding)
• Proposed upgrades
• Improve cryogenic system reliability (FY08)
• Reduce interference with magnet test program
  (FY08)
• Two more cryostats and staging area (FY09)

existing cryostat radiation shield
VTS cryogenic system upgrade
VTS 2 3 upgrade
AES01 cell 7

• Cavity diagnostics FY08
• 9-cell thermometry development
• Diagnostic instrumentation
• Variable input coupler, x-ray detectors, etc.
• RD through FY08
• GDE/S0 tests (with cavity surface processing at
  JLab and Argonne)
• Cavity vendor qualification (9-cells and
  single-cells)
• Test other types of cavities
• Single-spoke cavities for HINS
• Hydroformed cavities from DESY, etc.

• Fast thermometry - hot spot detection
• Cernox RTD (resistive thermometry device) sensors
  
• 10 kHz sampling rate
• Flexible placement, depending on test
  requirements
• Well tested and reliable system
• Used to pinpoint quench in AES01 cell 7

R

• 9-cell thermometry - hot spot detection
• System requirements
• Measure temperature rise, in a comprehensive
  pattern around each of the 9 cells, all 9 cells
  at once
• Fast installation
• Use for every 9 cell test
• Design
• For single-cell prototype - see N. Dhanaraj et
  al. poster
• G10 boards, kapton printed circuit
• Kapton loop provides spring to hold diodes
  against surface
• Diode sensors 1mm x 1mm sense area
• Diodes allow multiplexing without active
  multiplexer
• 960 diodes per cell 60 cards x 16 diodes/card
• 8640 diodes for a 9-cell cavity

z

• Variable RF input coupler
• Keeps cavity critically coupled
• Facilitates mode measurements useful for cavity
  diagnostics
• Mounts to standard input coupler port
• Movement range DR15 mm (2E9 . Qext . 4E10)