CEC Abstracts in PDF format (as of 7/3/07) - CEC-ICMC 2013

CEC 2007 - Abstracts
Friday, 07/20/07 Oral 9:15am -
10:45am
C4-B Superconducting RF Cavities and
Cryosystems - II
C4-B-01 ILC Cryogenic Systems Reference Design
T. Peterson, M. Geynisman, A. Klebaner, J.
Theilacker, Fermilab; V. Parma, L. Tavian, CERN.
A Global Design Effort began in 2005 to study a TeV scale electronpositron
linear accelerator based on superconducting radio-frequency
(RF) technology, called the International Linear Collider (ILC). In
early 2007, the design effort culminated in a reference design for the
ILC, closely based on the earlier TESLA design. The ILC will consist
of two 250 GeV linacs, which provide positron-electron collisions for
high energy physics research. The particle beams will be accelerated
to their final energy in superconducting niobium RF cavities operating
at 2 Kelvin. At a length of about 12 km each, the main linacs will be
the largest cryogenic systems in the ILC. Positron and electron
sources, damping rings, and beam delivery systems will also have a
large number and variety of other superconducting RF cavities and
magnets, which require cooling at liquid helium temperatures. Ten
large cryogenic plants with 2 Kelvin refrigeration are envisioned to
cool the main linac and the electron and positron sources. Three
smaller cryogenic plants will cool the damping rings and beam
delivery system components predominately at 4.5 K. This paper
describes the cryogenic systems concepts for the ILC.
C4-B-02 Installation and Commissioning of the
Superconducting RF Linac Cryomodules for the ERLP
A.R. Goulden, R. Bate, CCLRC Daresbury
Laboratory UK; R.K. Buckley, S.M. Pattalwar,
CCLRC Daresbury Labpratory UK.
An Energy Recovery Linac Prototype (ERLP) is currently being
constructed at Daresbury Laboratory (UK), to promote the necessary
skills in science & technology, particularly in photocathode electron
gun and Super Conducting RF, to enable the construction of a fourth
generation light source, based on energy recovery linacs-4GLS [1].
The ERLP uses two identical cryomodules, one as a booster cavity
accelerating the beam to 8.5 MeV, the other as a linac module in the
re-circulating loop with an energy gain of 24.5 MeV. Each module
consists of two nine cell cavities operating at a frequency of 1.3GHz
and a temperature of 2K. As there is no energy recovery in the booster
it requires a peak power of 53kW; whereas the linac module only
requires 8kW. The RF power is supplied by 4 IOTs. The maximum
heat load or the cooling power required in the Super Conducting RF
system is 180W at 2K and is achieved in two stages: a LN2 precooled
Linde TCF050 liquefier produces liquid helium at 4.5K,
followed by a 2K cold box consisting of a JT valve, recuperator and
an external room temperature vacuum pumping system.
This presentation reports the experience gained during, installation,
commissioning and the initial operation of the cryomodules.
C4-B-03 Initial Operating Experience for the ISAC-II
SC-Linac at TRIUMF
I. Sekachev, W. Andersson, R. Laxdal, G. Stanford,
TRIUMF.
A first stage of the heavy ion superconducting linac cryogenic system
comprising a 500W LHe refrigerator and distribution system has been
installed and started operation at TRIUMF. The early experience with
the cryogenic systems including data of the thermal loads and
refrigerator performance will be presented.
C4-B-04 Operation of the Superconducting Linac at the
Spallation Neutron Source.*
I. E. Campisi, F. Casagrande, M. Crofford, M.
Howell, Y. Kang, S. H. Kim, Z. Kursun, P. Ladd, D.
Stout, W. Strong, ORNL/SNS; M.S. Champion, FNAL.
At the Spallation Neutron Source, the first fully operational pulsed
superconducting linac has been active for about two years. During this
period, stable beam operation at 4.4 K has been achieved with beam
for repetition rates up to 15 Hz. Lower temperatures have been
occasionally attained to study conditions required to support full beam
power delivery, which requires 60 Hz RF and beam pulses of 1
millisecond. A large amount of data has been collected on the pulsed
behavior of cavities and cryomodules at various repetition rates and at
various temperatures. This experience will be of great value in
determining future optimizations of SNS as well in guiding in the
design and operation of future pulsed superconducting linacs.
This paper describes the details of the cryogenic system and RF
properties of the SNS superconducting linac.
*SNS is managed by UT-Battelle, LLC, under contract DE-AC05-
00OR22725 for the U.S. Department of Energy
C4-B-05 Cryogenic Infrastructure for Fermilab’s ILC
Vertical Cavity Test Facility
R. Carcagno, C. Ginsburg, Y. Huang, B. Norris, J.
Ozelis, T. Peterson, R. Rabehl, C. Sylvester, M. Wong,
Fermi National Accelerator Laboratory.
Fermilab is building a Vertical Cavity Test Facility (VCTF) to provide
for R&D and pre-production testing of bare 9-cell, 1.3 GHz
superconducting RF (SRF) cavities for the International Linear
Collider (ILC) program. This facility is located in the existing
Industrial Building 1 (IB1) where the Magnet Test Facility (MTF)
also resides. Helium and nitrogen cryogenics are shared between the
VCTF and MTF including the existing 1500W @ 4.5K helium
refrigerator with vacuum pumping for super-fluid operation (125 W
capacity at 2K).
The VCTF is being constructed in multiple phases. The first phase is
scheduled for completion in mid 2007, and includes modifications to
the IB1 cryogenic infrastructure to allow helium cooling to be directed
to either the VCTF or MTF as scheduling demands require. At this
stage, the VCTF consists of one Vertical Test Stand (VTS) cryostat
for the testing of one cavity in a 2 K helium bath.
Planning is underway to provide a total of three Vertical Test Stands
at VCTF, each capable of accommodating two cavities. Cryogenic
infrastructure improvements necessary to support these additional
VCTF test stands include a dedicated ambient temperature vacuum
pump, a new helium purification skid, and the addition of helium gas
storage.
This paper describes the system design and initial cryogenic operation
results for the first VCTF phase, and outlines future cryogenic
infrastructure upgrade plans for expanding to three Vertical Test
Stands.
C4-B-06 European XFEL-Linac Two-Phase Helium II
Flow Simulations
V. Gubarev, B. Petersen, D. Sellmann, DESY; Y.
Xiang, GSI.
The superconducting 1.3-GHz niobium cavities of the XFEL linear
accelerator will be cooled in a bath of liquid helium II at a
temperature of 2K. The liquid helium II supply of the 1.7-km long
linac is subdivided in sections of 150m length. In these sections a two
phase flow of helium II liquid and corresponding vapor occurs. A
stable stratified smooth helium flow has to be maintained for the RF
operation of the cavities, to avoid any microphonic effects. A
computer code has been developed to simulate the two phase flow in
the XFEL-linac. The flow characteristics at different cryogenic loads
and tube dimensions have been calculated. The results are shown and
the consequences for the design of the XFEL-cryomodules are
discussed.
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