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Results from the 'S1-Global' cryomodule tests at KEK (8-cav. and DRFS operation). Shin MICHIZONO (KEK). Outline I. 8-cavity installation (S1 global) Total eight cavities are installed. Rather short time operation (for total 3 months, Mon. to Fri. from 1PM to 7PM.) No beam operation - PowerPoint PPT Presentation
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1
Results from the 'S1-Global' cryomodule tests at KEK
(8-cav. and DRFS operation)
Shin MICHIZONO (KEK)
LOLB-2 (June, 2011)
OutlineI. 8-cavity installation (S1 global) Total eight cavities are installed. Rather short time operation (for total 3 months, Mon. to Fri. from 1PM to 7PM.) No beam operation With circulators at individual input couplerDynamic detuning control with piezo Vector sum operation Quench analysisII. DRFS operation (aiming for ilc) One klystron drives two cavities. Total 2 klystrons are used. No beam operation Without circulators Dynamic detuning control with piezo Slow detuning control with piezoIII. Future plan
Related topics-Performance-Diagnostics-Piezo control(8cav. &DRFS)-Quench phenomena (8cav. &DRFS)-Rf overhead (8 cav. &DRFS)- Circulator-less (DRFS)
LOLB-2 (June, 2011)2
LOLB-2 (June, 2011)3
LOLB-2 (June, 2011)4
S1 Global LLRF for 8 cav. operation All the cavities are driven by 5 MW klystron.
5LOLB-2 (June, 2011)
Digital LLRF system using an FPGA board on cPCI. 10 16bit-ADCs are installed.
6
loaded-Q interlock Calculate the loaded Q from the decay of the rf signal The interlock works well and contributes to the lower heat load to the cryogenics.
RF off
RF offDoneLOLB-2 (June, 2011)
7
Real time detuning monitor
The real time detuning monitor is quite helpful to adjust the Piezo tuners.
LOLB-2 (June, 2011)
detuned
8
Results from the 'S1-Global' cryomodule tests at KEK
(8-cav. and DRFS operation)
Shin MICHIZONO (KEK)
LOLB-2 (June, 2011)
OutlineI. 8-cavity installation (S1 global) Total eight cavities are installed. Rather short time operation (for total 3 months, Mon. to Fri. from 1PM to 7PM.) No beam operation With circulators at individual input couplerDynamic detuning control with piezo Vector sum operation Quench analysisII. DRFS operation (aiming for ilc) One klystron drives two cavities. Total 2 klystrons are used. No beam operation Without circulators Dynamic detuning control with piezo Slow detuning control with piezoIII. Future plan
Related topics-Performance-Diagnostics-Piezo control(8cav. &DRFS)-Quench phenomena (8cav. &DRFS)-Rf overhead (8 cav. &DRFS)- Circulator-less (DRFS)
Stabilities at 26 MV/m operation
0.0067%rms ( in amplitude),16.5mdeg.rms(in phase) @690 ~ 1590us
By T. Matsumoto
9LOLB-2 (June, 2011)
RF stabilities during 2H operation
10LOLB-2 (June, 2011)
Vector sum amplitude and phase are kept constant during 2H operation.
Gradient
Amplitude stability
Phase stability
11
Results from the 'S1-Global' cryomodule tests at KEK
(8-cav. and DRFS operation)
Shin MICHIZONO (KEK)
LOLB-2 (June, 2011)
OutlineI. 8-cavity installation (S1 global) Total eight cavities are installed. Rather short time operation (for total 3 months, Mon. to Fri. from 1PM to 7PM.) No beam operation With circulators at individual input couplerDynamic detuning control with piezo Vector sum operation Quench analysisII. DRFS operation (aiming for ilc) One klystron drives two cavities. Total 2 klystrons are used. No beam operation Without circulators Dynamic detuning control with piezo Slow detuning control with piezoIII. Future plan
Related topics-Performance-Diagnostics-Piezo control(8cav. &DRFS)-Quench phenomena (8cav. &DRFS)-Rf overhead (8 cav. &DRFS)- Circulator-less (DRFS)
LOLB-2 (June, 2011)12
Dynamic detuning compensation with piezo
13LOLB-2 (June, 2011)
Piezo works well to compensate the dynamic detuning
Detuning change during 2H operation
14LOLB-2 (June, 2011)
DESY: 33Hz, FNAL:12~38Hz, KEK: 5~10Hz
quench
Rather stiff at A-1~4. (~1/4 compared with C-1~4)
FNALDESY
KEK KEK KEK KEK
Ql change during operation
15LOLB-2 (June, 2011)
Ql changes are also observed at KEK. This is still open question. (difficult to explain by only coupler lod)
FNALDESY
KEK KEK KEK KEK
16
Results from the 'S1-Global' cryomodule tests at KEK
(8-cav. and DRFS operation)
Shin MICHIZONO (KEK)
LOLB-2 (June, 2011)
OutlineI. 8-cavity installation (S1 global) Total eight cavities are installed. Rather short time operation (for total 3 months, Mon. to Fri. from 1PM to 7PM.) No beam operation With circulators at individual input couplerDynamic detuning control with piezo Vector sum operation Quench analysisII. DRFS operation (aiming for ilc) One klystron drives two cavities. Total 2 klystrons are used. No beam operation Without circulators Dynamic detuning control with piezo Slow detuning control with piezoIII. Future plan
Related topics-Performance-Diagnostics-Piezo control(8cav. &DRFS)-Quench phenomena (8cav. &DRFS)-Rf overhead (8 cav. &DRFS)- Circulator-less (DRFS)
Cavity equation
17
The cavity should satisfy the differential equation. In addition directivity (~20dB) of rf monitor-coupler should be concerned. -> The directivity can be corrected using this formula.
LOLB-2 (June, 2011)
Vሶ=−൬ω12− j∆ω൰V+2ω12Vfor Vcavሶ − j∆ωVcav =ω1/2Vdif Vdif = Vfor −Vref Vcavሶ − j∆ωVcav =ω1/2Vdif VcavRሶ +∆ωVcavI =ω1/2VdifR VcavIሶ −∆ωVcavR =ω1/2VdifI ω12 =
12 ddta�Va�2Vfor2 −Vref2
𝐐𝐥=𝛚𝟎൫𝐕𝐟𝐨𝐫𝟐 −𝐕𝐫𝐞𝐟𝟐 ൯𝐝𝐝𝐭a�𝐕a�𝟐
Quench phenomena
18LOLB-2 (June, 2011)
Loaded Qs are calculated from cavity differential equation. Only the end of rf pulse shows the quench.
Rather stiff at A-1~4. (~1/4 compared with C-1~4)
Quench phenomena (2)
19LOLB-2 (June, 2011)
Detuning change at C-4 affects the VS leading to C-1 Quench
20
Results from the 'S1-Global' cryomodule tests at KEK
(8-cav. and DRFS operation)
Shin MICHIZONO (KEK)
LOLB-2 (June, 2011)
OutlineI. 8-cavity installation (S1 global) Total eight cavities are installed. Rather short time operation (for total 3 months, Mon. to Fri. from 1PM to 7PM.) No beam operation With circulators at individual input couplerDynamic detuning control with piezo Vector sum operation Quench analysisII. DRFS operation (aiming for ilc) One klystron drives two cavities. Total 2 klystrons are used. No beam operation Without circulators Dynamic detuning control with piezo Slow detuning control with piezoIII. Future plan
Related topics-Performance-Diagnostics-Piezo control(8cav. &DRFS)-Quench phenomena (8cav. &DRFS)-Rf overhead (8 cav. &DRFS)- Circulator-less (DRFS)
LOLB-2 (June, 2011)21
LOLB-2 (June, 2011)22
LOLB-2 (June, 2011)23
LOLB-2 (June, 2011)24
Schematic of the DRFS at S1-global
DRFS #1
DRFS #2
MA modulator
LOLB-2 (June, 2011)25
DRFS klystron and WG system with module
Feb.8 :
LOLB-2 (June, 2011)26
DRFS klystron and WG system
Feb.8 :
Phase shifter
Phase shifter
Some photos
27
DRFS #1
DRFS #2
Modulator on the ground
LOLB-2 (June, 2011)
Some photos (2)
28
DRFS #1
Phase shifter
MA modulator
LOLB-2 (June, 2011)
HLRF and LLRF
29LOLB-2 (June, 2011)
Magic-T and WG system LLRF rack is located just downstream of cryomodule-> radiation dose will be measured.
S1 Global 3rd stage (DRFS) ( 1 ) Digital system is located in the tunnel Fast interlock (and Arc detectors, VSWR meter) are located on the ground. cPCIs are used for the monitor and also they are the backup digital system.
30LOLB-2 (June, 2011)
31
Field regulation with uTCA
LOLB-2 (June, 2011)
cERL like uTCA FPGA system was installed. An FPGA board have 4 16-bit ADCs and 4 16-bit DACs. Two cavity-pickups, klystron output, reflection are observed. The system was located in the tunnel.
RF distribution at DRFS
One klystron drives two cavities. Circulator-less system.Same (amplitude and phase) reflection signals go to the dummy load.(blue line) Un-balanced reflection signals move to the klystron. (red line) -> careful operation is required to protect the klystron.
Phase-shifters are introduced to evaluate the system. (not to be used at ilc-DRFS)
32LOLB-2 (June, 2011)
Circulator-less system Elimination of circulators are proposed at DRFS. The study to eliminate the circulators were partly carried out at STF-1. However, there was a big circulator between cavities and a klystron. This is the first time to eliminate all the circulators.
Cavity input
Normalized by klystron output
Cavity input exists even after RF off
With circulators Without circulators
| Vf |
| Vf |
Vf a
mpl
itude
rat
io (
%)
Vf a
mpl
itude
rat
io (
%)
33LOLB-2 (June, 2011)
Results at STF-1
34
Results from the 'S1-Global' cryomodule tests at KEK
(8-cav. and DRFS operation)
Shin MICHIZONO (KEK)
LOLB-2 (June, 2011)
OutlineI. 8-cavity installation (S1 global) Total eight cavities are installed. Rather short time operation (for total 3 months, Mon. to Fri. from 1PM to 7PM.) No beam operation With circulators at individual input couplerDynamic detuning control with piezo Vector sum operation Quench analysisII. DRFS operation (aiming for ilc) One klystron drives two cavities. Total 2 klystrons are used. No beam operation Without circulators Dynamic detuning control with piezo Slow detuning control with piezoIII. Future plan
Related topics-Performance-Diagnostics-Piezo control(8cav. &DRFS)-Quench phenomena (8cav. &DRFS)-Rf overhead (8 cav. &DRFS)- Circulator-less (DRFS)
Cavity equation
35
The cavity should satisfy the differential equation. In addition directivity (~20dB) of rf monitor-coupler should be concerned. -> The directivity can be corrected using this formula.
LOLB-2 (June, 2011)
Vሶ=−൬ω12− j∆ω൰V+2ω12Vfor Vcavሶ − j∆ωVcav =ω1/2Vdif Vdif = Vfor −Vref Vcavሶ − j∆ωVcav =ω1/2Vdif VcavRሶ +∆ωVcavI =ω1/2VdifR VcavIሶ −∆ωVcavR =ω1/2VdifI ω12 =
12 ddta�Va�2Vfor2 −Vref2
𝐐𝐥=𝛚𝟎൫𝐕𝐟𝐨𝐫𝟐 −𝐕𝐫𝐞𝐟𝟐 ൯𝐝𝐝𝐭a�𝐕a�𝟐
Diagnostics (Ql evaluation)
36
The simple Ql estimation from decay curve does not work when the rf input exist after rf switched off. The calculated Ql values agree well between filling and decay. Although simple Ql calculation is useful for interlock, this is not sufficient for diagnostics.
LOLB-2 (June, 2011)
Ql at filling
Cav1
Cav2
Ql at decay
Ql from decay
37
Results from the 'S1-Global' cryomodule tests at KEK
(8-cav. and DRFS operation)
Shin MICHIZONO (KEK)
LOLB-2 (June, 2011)
OutlineI. 8-cavity installation (S1 global) Total eight cavities are installed. Rather short time operation (for total 3 months, Mon. to Fri. from 1PM to 7PM.) No beam operation With circulators at individual input couplerDynamic detuning control with piezo Vector sum operation Quench analysisII. DRFS operation (aiming for ilc) One klystron drives two cavities. Total 2 klystrons are used. No beam operation Without circulators Dynamic detuning control with piezo Slow detuning control with piezoIII. Future plan
Related topics-Performance-Diagnostics-Piezo control(8cav. &DRFS)-Quench phenomena (8cav. &DRFS)-Rf overhead (8 cav. &DRFS)- Circulator-less (DRFS)
Typical operation of VS control
Under the low reflection condition, VSWR is ~1.1.
38LOLB-2 (June, 2011)
Pf
Pb to kly.
Detuning and Ql under typical operation
Loaded Qs calculated simple time decay are not correct.
39LOLB-2 (June, 2011)
Cav. C-1
Cav. C-2
Red:Ql by decay
Blue: Ql by cavity eq.
Un-matched operation with VS control(different detuning)
Reflection to the klystron is ~25kW (max VSWR=3) Vector sum is still regulated. (0.04%rms, 0.06deg.rms)
40 LOLB-2 (June, 2011)
Pf
Pb to kly.
f1>f2
Un-matched operation (detuning and Ql)
Although Qls by decay show low-value, Qls based on cavity equation show reasonable values.
41LOLB-2 (June, 2011)
Cav. C-1
Cav. C-2
Red:Ql by decay
Blue: Ql by cavity eq.
Un-matched operation with VS control(different waveguide-length)
42 LOLB-2 (June, 2011)
Reflection to the klystron is ~20kW (max VSWR=2.8) Vector sum is still regulated. (0.015%rms,0.07deg.rms)
Pf
Pb to kly.f1~f2
Un-matched operation (detuning and Ql)
Ql by decay: ~4e6 Ql by cavity equation: ~2.5e6 43
LOLB-2 (June, 2011)
Cav. C-1
Cav. C-2
44
Results from the 'S1-Global' cryomodule tests at KEK
(8-cav. and DRFS operation)
Shin MICHIZONO (KEK)
LOLB-2 (June, 2011)
OutlineI. 8-cavity installation (S1 global) Total eight cavities are installed. Rather short time operation (for total 3 months, Mon. to Fri. from 1PM to 7PM.) No beam operation With circulators at individual input couplerDynamic detuning control with piezo Vector sum operation Quench analysisII. DRFS operation (aiming for ilc) One klystron drives two cavities. Total 2 klystrons are used. No beam operation Without circulators Dynamic detuning control with piezo Slow detuning control with piezoIII. Future plan
Related topics-Performance-Diagnostics-Piezo control(8cav. &DRFS)-Quench phenomena (8cav. &DRFS)-Rf overhead (8 cav. &DRFS)- Circulator-less (DRFS)
Adaptive detuning correction via EPICS
DC piezo bias is controlled every ~2 min. for detuning correction. The detuning after filling were kept constant
45LOLB-2 (June, 2011)
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
0 50 100 150 200 250
Piez
o co
ntro
l offs
et [V
]
time [min.]
detune control
control off
Even these simple (and slow) detuning correction looks promising to compensate the long-time detuning fluctuation (microphonics).
Piezo output to change from 0Hz to -50Hz
Detuning correction
LOLB-2 (June, 2011)46
RF waveform and detuning
47
Results from the 'S1-Global' cryomodule tests at KEK
(8-cav. and DRFS operation)
Shin MICHIZONO (KEK)
LOLB-2 (June, 2011)
OutlineI. 8-cavity installation (S1 global) Total eight cavities are installed. Rather short time operation (for total 3 months, Mon. to Fri. from 1PM to 7PM.) No beam operation With circulators at individual input couplerDynamic detuning control with piezo Vector sum operation Quench analysisII. DRFS operation (aiming for ilc) One klystron drives two cavities. Total 2 klystrons are used. No beam operation Without circulators Dynamic detuning control with piezo Slow detuning control with piezoIII. Future plan
Related topics-Performance-Diagnostics-Piezo control(8cav. &DRFS)-Quench phenomena (8cav. &DRFS)-Rf overhead (8 cav. &DRFS)- Circulator-less (DRFS)
LOLB-2 (June, 2011)48
RF overhead @flat-top
4%
Minimum 3% rf overhead is necessary.
If we allow 50Hz detuning, 7% overhead is required .
10% overhead necessary.
11%
Average power
Variation inside pulse
Long term stability (microphonics)
49LOLB-2 (June, 2011)
A-2
A-3
No piezo controlNo piezo control
Microphonics are about 3~5Hz rms. Since KEK cavities are stiff enough, the effect of adaptive piezo control is not clear.
Adaptive control
50
Results from the 'S1-Global' cryomodule tests at KEK
(8-cav. and DRFS operation)
Shin MICHIZONO (KEK)
LOLB-2 (June, 2011)
OutlineI. 8-cavity installation (S1 global) Total eight cavities are installed. Rather short time operation (for total 3 months, Mon. to Fri. from 1PM to 7PM.) No beam operation With circulators at individual input couplerDynamic detuning control with piezo Vector sum operation Quench analysisII. DRFS operation (aiming for ilc) One klystron drives two cavities. Total 2 klystrons are used. No beam operation Without circulators Dynamic detuning control with piezo Slow detuning control with piezoIII. Future plan
Related topics-Performance-Diagnostics-Piezo control(8cav. &DRFS)-Quench phenomena (8cav. &DRFS)-Rf overhead (8 cav. &DRFS)- Circulator-less (DRFS)
LOLB-2 (June, 2011)51
Future plan at STF Quantum beam project: with beam from Jan.2012. STF-2 project: with beam from April 2013.
LOLB-2 (June, 2011)52
Future planQuantum beam STF Phase2
Pulse length 1ms 0.9ms
Repetition rate 5Hz 5Hz
Bunch Spacing 6.15ns (162.5MHz) 369.27ns (2.708MHz)
Number of bunch/pulse 162500 2437
Bunch charge 62pC 3.2nC
Total charge /pulse 10,000nC 7,798nC
Beam current 10mA 8.7mA
Bunch length 12ps(Laser, FWHM) 10ps(Laser, FWHM)
Max. beam energy 40MeV 21.5MeV
Beam power 2.0kW (40MeV beam) 0.8kW (21.5MeV beam)
• RF gun cavity and input coupler were fabricated by FNAL. (DESY-FNAL-KEK collaboration)
• FNAL delivered gun cavity and input coupler in November 2009.
• RF process up to 1.7MW in 2010.
• More high power process (3.5MW) and beam extraction in 2011.
DESY-FNAL design RF gun,FNAL fabrication.
input coupler
Photocathode insertion
Photocathode RF gun for beam supply to Cryomodules
Photocathode RF-gun in STF
gun cavity
cavity
photocathode chamber
input coupler
Solenoid magnet
53LOLB-2 (June, 2011)
Two 9-cell cavities : 15.2MV/m operation
Capture Module
Cavities: MHI-012, MHI-013
Similar Structure to ILC Cryomodule, except the length
54LOLB-2 (June, 2011)
LOLB-2 (June, 2011)55
Thank you for your attention