Design and Prototype Progress toward a Superconducting Crab Cavity Cryomodule for the APS Page: 3 of 3
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Proceedings of IPAC
locations along the waveguide in order to minimize the
heat load to the 2K cryostat. For the nominal case where
Bsmax=100 mT, a 0.26W heat load was found where the
majority was due to the static heat migrating along the
copper coating on the stainless steel waveguide (Fig. 5).
The vertical branch of the "Y" waveguide will be used
as a HOM damper as well as the operating mode power
coupler. In addition, both low-power  and high-power
 RF load designs have been investigated for LOM and
a 50K -
"*F Lry -3=-1nh
Figure 5: 1-D thermal design optimization with 10 micron
Cu coated S.S. waveguide, AlMg seal on Nb flange and a
50K heat station.
LOM+Y dampers, amplitude
- onCell+Y dampers, amplitude
2onCelDogbone+Y dampers, amplitude
- APS longitudinal impedance upper limit (200mA)
MF kf -pd tn 1 sn\'- r uts
MAFIA Wakefield-impedance calculation for 16 single-cell crab uits
2 3 4 5 6
8 9 10
Figure 6: Monopole impedance comparison for three type
single-cell damping structures.
Figure 7: The 5-cell cavity design under the study.
'10, Kyoto, Japan WEPEC079
A 5-cell crab cavity design operating at the "0" mode
will improve the cryomodule packing factor, cryogenic
efficiency and reduce the waveguide dampers (see Figure
7). Its feasibility and effect on the beam quality is
currently under investigation.
After systematic R&D, prototyping, simulations and
analytical studies of various designs, a final baseline crab
cavity design will be chosen by the end of 2010 in order
to fully integrate an engineered cryomodule for the SPX
project. The major design parameters have been derived
and given in Table 1.
Table 1: Main design parameters of SPX cryomodule.
Parameter Value Unit
Frequency 2.815488 GHz
Cavity Type elliptical
Fundamental Mode TM110-y-0 vertical kick
RtIQ including TTF 35.8 0
Crabbing Voltage Vt at Bs-100mT 0.53 MV
Peak Surface Bs Field/Vt 195.6 mTMV
Peak Surface Es FieldIVt 82 1/m
Geometry Factor 227.5 n)
Material Thickness 3 mm N
Cavity Iris Radius 25 mm
Cavity A ctive Gap Distance 53.24 mm
Operational 00 a>1.iE+09 n rat 2K
Cell Number 1
1H01 + FPC Couplers 3 "Y" WGs
LOM Coupler r1 mWGlstub
Te110-x Mode 3.56 GHz
Lorentz Farce Detune (cal. max.) 10.5 kHz! IMV)
Tuner Coarse Range, +1- 200 kHz
Tuner Fine Range, +1- v25 kHz
Tuner Fine Resolution 4 Hz, no pieco
Operational Crabbin decrabing Voltage 4 h
Module Number 2 W
Cavity Number per module 8
Oe xt, T10110-y-0 1.2E+06
Kystron Power per Cavity 5 kW
Microphonic Amp. Limit +!- 6a 100 Hz
Cavity Stiffener ay not need if using fast LLRF
50K Static Heat Load (FPCs+Shield) 27+180 W
50K Dynamic Heat Load (FPCs+ Shield) 76+108 W
2K Static Heat Load per Cavity 2.4 W
2K Dynamic Heat Load per Cavity 7 W
Magnetic Field due to ReIar 0.1 mT
Axial Magretric Shielding Factor '100
HOM Longitudinal Impedance Upper Limit <0.5 M0-GHz
monopole HOMs, Rs=V^2C2P)]
HOM Horizontal Impedance Upper Limit Rt <1.4 M flm
di ole x-HOMs
HOM Vertical Impedance Upper Limit Rv <7.9 Mfllm
 H. Wang et al., Proc. PAC 2009, paper WE5PFP059.
 A. Zholents et al., NIM A 425, 385 (1999).
 Private communication with Y-C. Chae ,Sept, 2007.
AdvComp/ACE3P, SLAC's ACES Suite.
 C. Hovater, et al., Proc. PAC 2007, p2481.
 J. Shi et al., Proc. EPAC 2008, paper MOPP155.
 F. Marhauser, et al., Proc. PAC 2009, paper
 B. Brajuskovic, et al., Proc. PAC 2007, paper
07 Accelerator Technology
T07 Superconducting RF
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Haipeng Wang, Guangfeng Cheng, Gianluigi Ciovati, James Henry, Peter Kneisel, Robert Rimmer, Gary Slack, Larry Turlington, Geoff waldschmidt, Alireza Nassiri. Design and Prototype Progress toward a Superconducting Crab Cavity Cryomodule for the APS, article, May 1, 2010; Newport News, Virginia. (digital.library.unt.edu/ark:/67531/metadc837204/m1/3/: accessed October 20, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.