Progress of SC RF Cavity during the 2006-2007

Progress of SC RF CavityProgress of SC RF Cavityduring the 2006-2007during the 2006-2007

RF GroupRF Group

May 10, 2007May 10, 2007

The 5th IMAC of the BEPCII May 10, 2007The 5th IMAC of the BEPCII May 10, 2007

TopicsTopics

Final assembly of SC cavity module.Final assembly of SC cavity module. Module horizontal test and its performance.Module horizontal test and its performance. Tunnel installation and on-site alignment.Tunnel installation and on-site alignment. Machine commissioning Machine commissioning

for SR mode.for SR mode. for Physics mode.for Physics mode.

Puzzles of the vacuum I/L of the east modulePuzzles of the vacuum I/L of the east module ，， and whand where is the solution?ere is the solution?

Spare SC cavity module and key components developSpare SC cavity module and key components developmentment

The 5th IMAC of the BEPCII May 10, 2007The 5th IMAC of the BEPCII May 10, 2007Final Module Assembling from March to May Final Module Assembling from March to May 20062006 2006 Mar. 23~30, the IHEP #2 SCC module was assembled in the 2006 Mar. 23~30, the IHEP #2 SCC module was assembled in the

clean room of building 6. Prof. Mitsunobu came to IHEP and clean room of building 6. Prof. Mitsunobu came to IHEP and instruct us to perform this work, MELCO sent one S.V, Mr. Arakawa, instruct us to perform this work, MELCO sent one S.V, Mr. Arakawa, to witness the whole procedure and give us some suggestions in to witness the whole procedure and give us some suggestions in advance.advance.

2006 April. 26~May 3, the IHEP #1 SCC module was assembled. 2006 April. 26~May 3, the IHEP #1 SCC module was assembled. Prof. Furuya and Mitsunobu came to IHEP and instruct us, MELCO Prof. Furuya and Mitsunobu came to IHEP and instruct us, MELCO sent two S.V, Dr. Kijima and Mr. Okada, to witness this procedure.sent two S.V, Dr. Kijima and Mr. Okada, to witness this procedure.


2. Assemble the damper 2. Assemble the damper with the beam taperwith the beam taper

3. Mount the 3. Mount the damper on the damper on the cryostatcryostat

4. Mount the 4. Mount the coupler on the coupler on the cryostatcryostat

1. Cavities are ready for 1. Cavities are ready for final assembly in final assembly in building sixbuilding six

6. Some of participators6. Some of participators5. Pre-assemble 5. Pre-assemble doorknob on to the doorknob on to the coupler portcoupler port

The 5th IMAC of the BEPCII May 10, 2007The 5th IMAC of the BEPCII May 10, 2007Log for Horizontal Test from May to August Log for Horizontal Test from May to August 20062006 2006 May~ June, the horizontal test for the IHEP #2 SC module.2006 May~ June, the horizontal test for the IHEP #2 SC module.

Coupler aging at room temperature, instructed by Prof. Furuya.Coupler aging at room temperature, instructed by Prof. Furuya. To cool down SC module to 4.5K.To cool down SC module to 4.5K. Coupler aging at 4.5K.Coupler aging at 4.5K. 2006.06.26~30, we carried out final performance test under the instruction of Prof. Furuya, two 2006.06.26~30, we carried out final performance test under the instruction of Prof. Furuya, two

S.V, Ms. Kijima and Mr. Arakawa, came to IHEP to check our equipment and witness this procedS.V, Ms. Kijima and Mr. Arakawa, came to IHEP to check our equipment and witness this procedure.ure.

During the conditioning period of the cavity, a B.D happen at 1.5MV, B.D detector miss to take aDuring the conditioning period of the cavity, a B.D happen at 1.5MV, B.D detector miss to take an actionn action ，， the pressure of LHe vessel increases up to more than 1.3bar, and the spring valve wathe pressure of LHe vessel increases up to more than 1.3bar, and the spring valve was opened automatically and a amount of cooled helium gas leaked from pipe of the spring valve.s opened automatically and a amount of cooled helium gas leaked from pipe of the spring valve.

2006 July~ August, the horizontal test for the IHEP #1 SC module.2006 July~ August, the horizontal test for the IHEP #1 SC module. Coupler aging at room temperature by us.Coupler aging at room temperature by us. To cool down SC module to 4.5K.To cool down SC module to 4.5K. Coupler aging at 4.5K.Coupler aging at 4.5K. 2006.08.24~26, the final performance tested by us, one S.V, Mr. Okada, 2006.08.24~26, the final performance tested by us, one S.V, Mr. Okada,

came to IHEP to check our equipment and witness this procedure.came to IHEP to check our equipment and witness this procedure. During the cooling down period of the cavity, we forgot to close the by-During the cooling down period of the cavity, we forgot to close the by-

pass valve of the cooling helium gas for the coupler, the flow rate of the pass valve of the cooling helium gas for the coupler, the flow rate of the helium gas is extremely high and a great lot of cooled helium gas pass helium gas is extremely high and a great lot of cooled helium gas pass through the return line, and some ice was frozen around the coupler through the return line, and some ice was frozen around the coupler port.port.


Horizontal TestHorizontal Test

1. Dummy tank test for 1. Dummy tank test for cryogenic system cryogenic system commissioningcommissioning

3. Clean up the ceramic 3. Clean up the ceramic windows of the windows of the couplercoupler

4. Added a compensating 4. Added a compensating spring to detune the spring to detune the frequency frequency

5. Coupler frozen by a huge 5. Coupler frozen by a huge amount of cold helium amount of cold helium gasgas

6. the coupling of coupler 6. the coupling of coupler changes from under to changes from under to over matchingover matching

2. Move the cavity 2. Move the cavity module to horizontal module to horizontal test roomtest room

The 5th IMAC of the BEPCII May 10, 2007The 5th IMAC of the BEPCII May 10, 2007SSpecificationpecification

/Condition/Condition

IHEP-#1IHEP-#1

(West module)(West module)

IHEP-#2IHEP-#2

(East module)(East module)

MeasureMeasurementment D Dateate 2006/06/302006/06/30 2006/08/262006/08/26

FrequencyFrequency

/Vertical test/Vertical test

@[email protected]

//[MHz][MHz]

499.344499.344 499.176499.176

FrequencyFrequency

/Horizontal test/Horizontal test

@Room Temp.@Room Temp.

//[MHz][MHz]

49499.1779.177 498.498.900900

FrequencyFrequency

/Horizontal test/Horizontal test

@[email protected]

//[MHz][MHz]

499.499.977977

(high than target value)(high than target value)

499.499.700700

FrequencyFrequency On-tuning /On-tuning /[MHz][MHz] 499.8499.8 499.8499.8

Tuning sensitivityTuning sensitivity 139kHz /100kg139kHz /100kg 123kHz /100kg123kHz /100kg

Spring constantSpring constant 0.38mm /100kg0.38mm /100kg 0.36mm /100kg0.36mm /100kg

Vc max [MV]Vc max [MV] 2.02.0 /MV /MV 2.02.0

/2.3 @/2.3 @20020077/0/044//26)26)

2.02.0

/2.1 @/2.1 @20020077/0/044//2626

Field limitationField limitation not limitednot limited ThermalThermal B.D B.D

QQ00 @2MV@2MV 00..55E+09E+09 0.990.99E+09E+09 0.0.5555E+09E+09

Qext (Coupler port)Qext (Coupler port) 1.9E+051.9E+05 1.1.99E+E+0505 2.12.1E+E+0505

Static loss Static loss [[WW]] 35 ?35 ? 27.227.2 2929


Horizontal test performance of the IHEP-#1 Horizontal test performance of the IHEP-#1 SCCSCC


Horizontal test performance of the IHEP-#2 Horizontal test performance of the IHEP-#2 SCCSCC


Shrinking length of the beam pipe during cooling down of the Shrinking length of the beam pipe during cooling down of the cavity modulecavity module

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1. SBP of IHEP #1 SC cavity1. SBP of IHEP #1 SC cavity

2. LBP of IHEP #1 SC cavity2. LBP of IHEP #1 SC cavity

3. SBP of IHEP #2 SC cavity3. SBP of IHEP #2 SC cavity

4. LBP of IHEP #1 SC cavity4. LBP of IHEP #1 SC cavity


Tunnel installation from August to Nov. 2006Tunnel installation from August to Nov. 2006

Cryogenic group run the dummy load at the site of the tunnel, Cryogenic group run the dummy load at the site of the tunnel, to test the LHe and LN2 transfer line and cryogenic system.to test the LHe and LN2 transfer line and cryogenic system.

Measure the itself alignment data of the SC cavity module at Measure the itself alignment data of the SC cavity module at off-line.off-line.

Move Cavity module to the beam line. Move Cavity module to the beam line. Adjust and align the cavity on to the beam lineAdjust and align the cavity on to the beam line Connect cavity with the neighboring beam chamber by RF-Connect cavity with the neighboring beam chamber by RF-

shielded bellow in a local clean booth. shielded bellow in a local clean booth. Prepare and connect cooling water system for HOM damper and Prepare and connect cooling water system for HOM damper and

high power coupler.high power coupler. Prepare and mount temperature sensor, pressure sensor and Prepare and mount temperature sensor, pressure sensor and

flow meter for each SC module.flow meter for each SC module.


Tunnel installationTunnel installation

Alignment Data for East & West SCC Module

1. Transverse direction (X_Y-axes)

SCC No.SBP Gate Valve Position LBP Gate Valve Position

XHorizontal

YVertical

XHorizontal

YVertical

East SCC -0.05 +3.7 +2.5 +1.1

West SCC +0.7 -1.2 -2.3 -1.1

2. Longitudinal direction (Z-axes)

SCC No.SBP beam pipe/mm

Cryostat/mm

LBP beam pipe/mm

Total length/mm

Length error/mm

Design 822 1427 1236 3485 0.0

East SCC --- --- --- 3489.2 4.2

West SCC 824.3 1428 1234.7 3487 2


1. West SC module in positron beam 1. West SC module in positron beam lineline

5. Chiller for the coupler5. Chiller for the coupler

3. A local clean booth used 3. A local clean booth used for cavity tunnel for cavity tunnel installationinstallation

2. East SC module in electron beam 2. East SC module in electron beam lineline

4. Monitors array of temperature, 4. Monitors array of temperature, pressure and flow meter for pressure and flow meter for cavitycavity

6. Cavity vacuum gauge 6. Cavity vacuum gauge controllercontroller


Machine CommissioningMachine Commissioning During beginning commissioning, RF During beginning commissioning, RF

trip happen frequently during several trip happen frequently during several days, the signal is recorded by a days, the signal is recorded by a scope as right. Final we found that it scope as right. Final we found that it is due to the instability of amplitude is due to the instability of amplitude feedback loop, the loop damping is feedback loop, the loop damping is not sufficient, by adjusting the loop not sufficient, by adjusting the loop damping knob, we settle down this damping knob, we settle down this problem.problem.

Accelerating Accelerating VoltageVoltage

Reflected Reflected PowerPower

Incident PowerIncident Power

Beam Current Beam Current DensityDensity

Once time, the east cavity vacuum Once time, the east cavity vacuum goes bad, even applying a low goes bad, even applying a low cavity voltage, vacuum I/L happens cavity voltage, vacuum I/L happens frequently, we decide to aging the frequently, we decide to aging the cavity to degas the cell surface. cavity to degas the cell surface. Final a breakdown occurs, by a Final a breakdown occurs, by a mass analyzer, we found a great of mass analyzer, we found a great of hydrogen released, and cavity hydrogen released, and cavity recovered from this breakdown.recovered from this breakdown.


Commissioning cont’...Commissioning cont’... During a routine cavity conditioning During a routine cavity conditioning

on Jan. 30 2006, a breakdown on Jan. 30 2006, a breakdown occurred for east module, since the occurred for east module, since the B.D detector miss to cut off RF power, B.D detector miss to cut off RF power, the pressure of LHe vessel rises up, the pressure of LHe vessel rises up, the electric safety valve was opened. the electric safety valve was opened. After taking this action, but the After taking this action, but the electric valve didn’t close after a short electric valve didn’t close after a short time, the rotation shaft of the valve time, the rotation shaft of the valve was frozen and couldn’t be closed by was frozen and couldn’t be closed by operator, we use a heater to warm up operator, we use a heater to warm up the frozen shaft, and close the electric the frozen shaft, and close the electric valve.valve.


Difficulties...Difficulties... 2006 Nov. 12~2007 Feb. 5, the BEPCII start to commissioning to clean up 2006 Nov. 12~2007 Feb. 5, the BEPCII start to commissioning to clean up

the vacuum chamber by beam, only the east cavity module used in SR the vacuum chamber by beam, only the east cavity module used in SR commissioning.commissioning.

Nov. 18, 2006, first time the beam caught by RF bucket and Nov. 18, 2006, first time the beam caught by RF bucket and accumulate in storage ring.accumulate in storage ring.

Dec. 13, 2006, the max beam current reach to 90mA at 2.5GeV in SR Dec. 13, 2006, the max beam current reach to 90mA at 2.5GeV in SR operation.operation.

From Jan 22~26 ,2007, Prof. Furuya visited IHEP, the BEPCII From Jan 22~26 ,2007, Prof. Furuya visited IHEP, the BEPCII accumulated beam current up to 178mA at 2.5GeV in SR mode on accumulated beam current up to 178mA at 2.5GeV in SR mode on 23rd Jan., while a accelerating voltage of 1.3MV applied to accelerate 23rd Jan., while a accelerating voltage of 1.3MV applied to accelerate the beam by the east accelerating module.the beam by the east accelerating module.


Difficulties cont’...Difficulties cont’... From 2007 Feb. 8 to now, the BEPCII start to commissioning in From 2007 Feb. 8 to now, the BEPCII start to commissioning in

colliding mode.colliding mode. For positron storage ring (West SC module), the beam current For positron storage ring (West SC module), the beam current

increased smoothly, up to now, it can accumulated beam current of increased smoothly, up to now, it can accumulated beam current of 150mA stably.150mA stably.

For electron storage ring (East SC module), the beam current For electron storage ring (East SC module), the beam current increased slowly, the vacuum I/L occurred frequently. increased slowly, the vacuum I/L occurred frequently.

Since the condition of the vacuum of east module went bad Since the condition of the vacuum of east module went bad gradually, we decided to warm up both SC cavity during the gradually, we decided to warm up both SC cavity during the period of spring holiday, from Feb. 20 to 22, the cavities warmed period of spring holiday, from Feb. 20 to 22, the cavities warmed up to max 88K and keep several hours to degas condensed gas.up to max 88K and keep several hours to degas condensed gas.

In order to find the reason that the vacuum went bad quickly In order to find the reason that the vacuum went bad quickly during injection, on mar. 23, 2007, the BEPCII changed to S.R run during injection, on mar. 23, 2007, the BEPCII changed to S.R run mode temporary, the beam current of 100mA can be accumulated mode temporary, the beam current of 100mA can be accumulated by the east module, while the west module is offset from resonant by the east module, while the west module is offset from resonant frequency, no vacuum I/L happen.frequency, no vacuum I/L happen.


1. East SC module in positron beam 1. East SC module in positron beam line (injected beam 80~100mA)line (injected beam 80~100mA)

2. West SC module in electron beam 2. West SC module in electron beam line (injected beam 50~150mA)line (injected beam 50~150mA)

We recorded the mass analyzer signal during injection and We recorded the mass analyzer signal during injection and operation period of both module, the period is from 22nd to 23nd operation period of both module, the period is from 22nd to 23nd April, 2007.April, 2007.


1. Mass analyzer signal during 1. Mass analyzer signal during warming up east SC module up warming up east SC module up to 100Kto 100K

2. Mass analyzer signal during 2. Mass analyzer signal during warming up west SC module up warming up west SC module up to 100Kto 100K

Again from 2007 April 24 to 26, we warmed up both cavity to 100K Again from 2007 April 24 to 26, we warmed up both cavity to 100K to release condensed gas on cavity surface, also mass analyzer to release condensed gas on cavity surface, also mass analyzer signal were recorded.signal were recorded.


Budget for Spare ModuleBudget for Spare Module

ItemItem AmountAmount /RMB Yuan/RMB Yuan

Nb cell (material, fabrication and test device)Nb cell (material, fabrication and test device) 1 piece1 piece 3’122’0003’122’000

Coupler (including aging bench)Coupler (including aging bench) 1 piece1 piece 2’390’0002’390’000

HOM damperHOM damper 1 set (SBP & LBP HOM damper)1 set (SBP & LBP HOM damper) 1’600’0001’600’000

Vacuum components (Gate valve, ion pump and Vacuum components (Gate valve, ion pump and etc.)etc.)

1 set1 set 1’291’0001’291’000

Clean room (including assembly tools)Clean room (including assembly tools) 1 set1 set 460’000460’000

Cryostat (including sensor, valve and etc.)Cryostat (including sensor, valve and etc.) 1 set1 set 3’150’0003’150’000

Other components (Tuner, heater and etc.)Other components (Tuner, heater and etc.) 1 set1 set 267’000267’000

Spare budgetSpare budget 600’000600’000

TotalTotal 12’880’00012’880’000

*** This project already got the permission of government, and it will be *** This project already got the permission of government, and it will be performed from 2007 to 2009.performed from 2007 to 2009.


AcknowledgementAcknowledgement During the past year, several time, Prof. Furuya, Mitsunobu and During the past year, several time, Prof. Furuya, Mitsunobu and

Akai visited IHEP to instruct us in module assembling, horizontal Akai visited IHEP to instruct us in module assembling, horizontal test and final success RF commissioning. Supervisors from MELCO test and final success RF commissioning. Supervisors from MELCO help us check our equipments and tools, and deliver necessary help us check our equipments and tools, and deliver necessary technique document to us. and thanks Prof. Kurokawa for his technique document to us. and thanks Prof. Kurokawa for his concern on SC cavity.concern on SC cavity.

Now the spare SC module already started up, we wish KEK can Now the spare SC module already started up, we wish KEK can supported us as before, RF group of KEKB, SSRF and BEPCII should supported us as before, RF group of KEKB, SSRF and BEPCII should be collaborated very tightly in future SRF technology development, be collaborated very tightly in future SRF technology development, especially in the aspects of niobium cavity fabrication and test, especially in the aspects of niobium cavity fabrication and test, high power coupler research and HOM damper construction.high power coupler research and HOM damper construction.

Documents

Progress of SC RF Cavity during the 2006-2007