1. Vertical Test System and T-mapping/X-ray-mapping at KEK-STF
Y. Yamamoto, H. Hayano, E. Kako, S. Noguchi, H. Sakai, M. Satoh, T. Shishido, K. Umemori, K. Watanabe (KEK, Japan)
Commissioning Test
TUPPO 038]
AES#001 cavity was used, which was on loan from FNAL.
Pinpoint attachment
at suspicious spot
Successful!
Summary
Abstract
The new vertical test facility was completed at STF and it is routinely used without any trouble. The commissioning test for the system check was successful by using the AES#001 cavity. The T-mapping and X-ray-mapping system was completed and the heating location at the quenching was perfectly detected. There was a correlation between the heating location and the X-ray emission site, when the cavity has a heavy field emission. In the near future, a new DAQ system using EPICS will be introduced, which is under developing.
Suspicious spots
A new vertical test facility was built in KEK-STF (Superconducting rf Test Facility) and in operation since July/2008. After the commissioning tests using AES#001 cavity which was on loan from FNAL, vertical test was routinely started for S1-Global project at KEK-STF. At the same time, a new T-mapping system was introduced for the identification of the heating location at the thermal quenching, which has 352 carbon resistors and is capable of more certainly identifying that, compared to the original T-mapping system. Recently, a new X-ray-mapping system is also completed.
Suspicious spots at #3 cell
Vertical Test System at STF
T-mapping/X-ray mapping System & Results
Content
Feature
Cryostat
4m height, φ520mm, 10W (static loss)
Pumping system
Rotary pump (4,000ℓ/min) x 2,
Mechanical booster pump (15,000ℓ/min) x 2
Radiation Shielding
16cm thickness, Iron plate, Movable/Fixed type
High Power RF Amplifier
Max. 400W, Min. 100W, 1240~1310MHz, Stability: 3%
Cavity Hanger Stand
3m height, Setting for 4 cavities
Data Acquisition System
LabVIEW (present), EPICS (future)
Content
Feature
T-mapping
352 carbon resistors (Allen-Bradley, 50 and 100Ω)
X-ray-mapping
142 PIN diodes (HAMAMATSU, S )
Sampling time
0.1sec
Data logger
MX100/MW100 (YOKOGAWA)
PXI2501/4071/6225 (National Instruments)
DAQ system
EPICS (future)
MHI#5
MHI#9
1st power mode
Equator of #2 cell π
7π/9
5π/9 π
8π/9
3π/9
6π/9
4π/9
Summary of T-mapping result at STF
cavity
# of V.T.
Eacc, max [MV/m]
heating mode
cause of limitation for π mode
heating pass-band modes
radiation level
@Eacc, max[μSv/h]
AES#001
2nd
15.7 #3
found defect
6, 8π/9
464
3rd
21.8
#5 &
>1000
MHI#5
1st
27.3 #5
defect or contamination
#1 &
19.7 #8
4, 8π/9
#1 &
143
27.1
5, 7π/9
6π/9
303
MHI#6
25.7 #7
field emission
4th
19.6 #9
multipacting
(?)
5th
22.1 ?
cable breakdown
56000
MHI#7
16.5 #1
3220
MHI#8
16.0 #2
4, 8π/9
6π/9
268
MHI#9
25.0
(#2)
4π/9
8π/9
>99000
T-mapping
X-ray-mapping
2nd power mode
Equator of #9 cell