pep-ii rf system status and upgrades
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Vojtech Pacak, PEP-II MAC Review, January 18-20 2006
PEP-II RF System Statusand
Upgrades
By: Vojtech PacakKlystron Department
PEP-II Machine Advisory Committee ReviewJanuary 18-20 2006
Vojtech Pacak, PEP-II MAC Review, January 18-20 20062
Summary
1. RF system performance– Configuration inventory
2. Status of selected problems reported in Dec 2004 MAC meeting
3. RF aborts, run 5A/B– List of leading abort causes
4. Klystron status– Limitations and Spare klystrons
5. RF system upgrades– New HER stations 10 and 11
6. Conclusions
Vojtech Pacak, PEP-II MAC Review, January 18-20 20063
Cavity Parameter
HER LER
Jul 2004
Run 4
Oct 2005
PEAK
Run 5A
PredictedMaximum
Run 6
Jul 2004
Run 4
Oct 2005
PEAK
Run 5A
Predicted Maximum
Run 6
RF Voltage/Ring (MV) 16 13.4 18.5 3.8 4.5 5.5
Number of Klystrons 8 9 11 3 4 4
Number of Cavities 26 26 28 6 8 8
Gap Voltage/Cavity (kV) 615 515 661 633 562 687
Dissipated Power/Cavity (kW) 51 36 59 54 42 63
Beam Power/Cavity (kW) 215 242 285 289 2.64 372
Total RF Power/Cavity (kW) 266 278 344 343 306 435
Klystron Power (kW) 940 970 979 757 700 980
Beam Current (A) 1.55 1.74 2.2 2.45 2.94 4.0
1) RF System Configuration – Runs 4-5-6*
* Luminosity predictions assuming y, y* and n remain fixed.
Peak Lumin. (1033 cm-2sec-1) 9.213 10.025 15.1* 9.213 10.025 15.1*
Vojtech Pacak, PEP-II MAC Review, January 18-20 20064
2) Status of Selected Problems Reported in Dec 2004• Stuck/Slow Tuners
– Found a software bug causing the motor controllers to hung up. New software installed in SPEAR3. Software will be installed in PEPII.
• SCR Stacks– Problem of leaking hermetic oil seals of SCR’s fixed.– All phasing SCR’s work fine.– Crowbar SCR’s develop excessive leakage in certain manufacturing
lots. Investigated by SLAC and EUPEC .• HER 12-6 Cavity Arcs
– Was traced to arcing in the cavity monitor probe• A new probe installed in the auxiliary cavity probe location fixed the problem.
• HER 8-3 Cavity D Arcs– Still not understood why the cavity probe signal would increase with the
increase of cavity reflected power.– Occurrence increases with HER beam current.– Could be caused by arcing in the coupler box?
Vojtech Pacak, PEP-II MAC Review, January 18-20 20065
3) Run 5A Abort Statistics, 4/21/05-10/17/05
Average of 4.5 Aborts/Day(2.8 Aborts/Day without non-RF events)
Compared to 2.9/Day for Run 4
Courtesy: Dan Van Winkle
Station Faults
ler 232
her 69
HR21 68
LR43 57
LR42 55
HR81 50
HR25 45
HR83 41
HR22 37
HR41 33
HR26 28
LR45 23
HR23 20
LR44 16
HR85 15
Subsystem Faults
HER RF 337
LER RF 151
HER other 69
LER other 232
Last event Count Stations Description
09/05/2005 88 multiple Transverse instability (TFB)
10/10/2005 48 ler(40),her(8) didt with transverse
10/09/2005 41 multiple Klystron arc
10/08/2005 37 ler(28),her(9) didt no motion
10/04/2005 34 multiple Unknown
10/10/2005 31 ler(25),her(6) Longitudinal instability
09/09/2005 30 multiple HVPS dip or rise
09/19/2005 29 multiple Cavity 1 arc (RE reported)
10/05/2005 27 multiple Cavity 2 arc (RE reported)
10/01/2005 23 multiple Transformer/crowbar
09/01/2005 23 multiple Cavity 1 vacuum
08/15/2005 19 HR81(1),HR85(1),HR21(17) Cavity 1 arc
09/24/2005 19 multiple Slow or stuck tuners
10/07/2005 18 ler Longitudinal instability (LFB tuning)
08/05/2005 16 multiple Klystron sideband oscillation
08/14/2005 16 HR83(14),HR85(2) Cavity 4 arc (RE reported)
09/12/2005 14 multiple Timing issue (missing fiducial/ref dropout)
10/09/2005 13 multiple Cavity 2 vacuum
10/05/2005 12 multiple Difficult to Configure Station
06/30/2005 11 LR43(8),HR21(1),HR25(2) Network/IOC Issues
Vojtech Pacak, PEP-II MAC Review, January 18-20 20066
3) Run 5B Abort Statistics, 10/11/05-1/17/06
Average of 5.5 Aborts/Day(0.8 Aborts/Day without non-RF events)
Compared to 2.9/Day for Run 4Courtesy: Dan Van Winkle
Station Faults
her 272
ler 162
LR44 36
HR26 21
HR22 5
HR21 3
HR83 2
HR81 2
HR85 1
HR41 1
LR43 1
LR42 1
Subsystem Faults
HER RF 35
LER RF 38
HER other 272
LER other 162
Last event Count Stations Description
01/11/2006 243 her Radiation with/without Transverse
01/10/2006 140 ler(138),her(2) didt with transverse
01/06/2006 26 LR44 Drive Glitch
01/01/2006 15 ler(13),her(2) didt no motion
11/30/2005 12 HR26 Klystron Output RE
01/02/2006 11 ler(1),her(10) Power dip (Region 8 or 4)
12/26/2005 8 multiple Unknown
01/06/2006 6 ler(1),her(5) Longitudinal instability
12/19/2005 5 LR43(1),ler(4) Pilot error
01/11/2006 5 LR44 Clock module problem
12/18/2005 4 ler Beam Loss leading to Loss of Control
01/09/2006 4 LR44 Slow or stuck tuners
12/27/2005 3 her Site Power Dip
12/03/2005 3 HR26 Tuner readback Fault
12/21/2005 3 HR26 Cavity Water Flow
12/06/2005 3 ler(1),her(2) Other with Y Transverse Motion
11/28/2005 3 HR22 Klystron sideband oscillation
12/06/2005 2 her Other with X Transverse Motion
12/19/2005 2 HR26 High forward Power (beam loading)
12/25/2005 2 HR85(1),HR21(1) Klystron vacuum
Vojtech Pacak, PEP-II MAC Review, January 18-20 20067
3) Leading RF caused aborts – run 5A/B
• Cav1(2) arcs, Cav1(2) vacuum, 75,36 counts– Majority (~80%) in HER 8-1 and HER 12-1.These trips have been observed for many years.
Cav1 is the first the beam enters after the beam pipe arcs. The deposit of out gassing debris from the arcs into these cavities are believed to be the probable cause.
• Typically the operating voltage of these cavities is reduced to limit arcing
• Klystron Arc, 41 counts– About 50% of reported aborts happened during testing, (Philips #7,LER 4-3), or during the HV
processing of the klystron, (Philips #8,HER 12-6).– Observed arcing in Philips #7, (LER4-3).
• klystron voltage set < 73 kV
• HVPS dips or rise, 30 counts– Few milliseconds voltage reduction or rise leads to klystron oscillations. Affected HER 4-1
and LER 4-2• HVPS re-phased
• Drive glitch, LER 4-4, 26 counts• Station LLRF power supply has been changed. Problem may be fixed, but need more confirmation.
• Klystron output RE, HER 12-6, 12 count• Corrected by adjusting circulator coil current.
• Power dips, 11 counts– HV reduction in all RF stations in the region. Mostly region 8, also observed in region 4.
• Ongoing investigation
Vojtech Pacak, PEP-II MAC Review, January 18-20 20068
4) Klystron Issues
Output power limitation on 4 klystrons:• HER 4-1 (Philips #2)
– Klystron saturation in Philips #2, power limited at ~ 850 kW• Adjusted klystron focus magnetic field, output match, circulator bias and waveguide length – no
improvement!• HER 12-1 (Philips #6)
– Klystron saturation in Philips #6, power limited at ~ 750 kW– Evidence of multipacting
• HER 12-2 (SLAC #6)– Sideband oscillations 15 MHz, power limited at ~850 kW
• Tuning of the circulator may mitigate the problem• LER 4-5 (Philips #3)
– Klystron saturation in Philips #3, power limited at ~850 kW, sideband oscillation 3 MHz
Hours of Operation:• HER 12-5, HER 4-1, HER 12-3, LER 4-5
– Klystrons Philips #’s 1, 2, 3 and SLAC #1 near or exceeding 50,000 filament hours
Spare Klystron Status• Currently Philips #5 is the only spare until SLAC #8 is tested
– It has deformed collector body and is power limited to ~ 600 kW
• Only after installation of the new SLAC klystrons there will be more Philips tubes as spares
Vojtech Pacak, PEP-II MAC Review, January 18-20 20069
4) Klystron Manufacturing Schedule
Klystron Start bake Scheduled Test
Complete
Comment
SLAC #8 completed 3/6/06 Replace Philips #6, HER 12-1
SLAC #7 completed 4/11/06 Replace Philips #1, HER 12-5
SLAC #9 2/23/06 5/17/06 Replace Philips #2, HER 4-1
SLAC #10 4/5/06 6/23/06 New installation, HER 12-4
Philips #4 n/a 8/1/06 Rebuilt at CPI, new installation HER 4-6
Philips #8 n/a 9/15/06 Rebuilt at CPI, replace Philips #3, LER 4-5
SLAC #11 9/17/06 11/16/06 Replace Philips #7, LER 4-3
SLAC #12 11/6/06 1/15/07 Replace Marconi #1, LER 4-4
Courtesy: Chris Pearson, KLY
Vojtech Pacak, PEP-II MAC Review, January 18-20 200610
4) Klystron Replacement Schedule
Station Q2 2005 Q3 2005 Q4 2005 Q1 2006 Q2 2006 Q3 2006 Q4 2006 >Q1 2007
LER 4-2 Marconi 4 Marconi 4 Marconi 4 Marconi 4 Marconi 4 Marconi 4 Marconi 4 Marconi 4
LER 4-3 Philips 5 Philips 7 Philips 7 Philips 7 Philips 7 Philips 7 Philips 7 SLAC 11
LER 4-4 Marconi 1 Marconi 1 Marconi 1 Marconi 1 Marconi 1 Marconi 1 Marconi 1 SLAC 12
LER 4-5 Philips 3 Philips 3 Philips 3 Philips 3 Philips 3 Philips 3 Philips 8 Philips 8
HER 4-1 Philips 2 Philips 2 Philips 2 Philips 2 SLAC 9 SLAC 9 SLAC 9 SLAC 9
HER 4-6 N/A N/A N/A N/A N/A Philips 4 Philips 4 Philips 4
HER 8-1 SLAC 5 SLAC 5 SLAC 5 SLAC 5 SLAC 5 SLAC 5 SLAC 5 SLAC 5
HER 8-3 SLAC 3 SLAC 3 SLAC 3 SLAC 3 SLAC 3 SLAC 3 SLAC 3 SLAC 3
HER 8-5 SLAC 4 SLAC 4 SLAC 4 SLAC 4 SLAC 4 SLAC 4 SLAC 4 SLAC 4
HER 12-1 Philips 6 Philips 6 Philips 6 SLAC 8 SLAC 8 SLAC 8 SLAC 8 SLAC 8
HER 12-2 SLAC 6 SLAC 6 SLAC 6 SLAC 6 SLAC 6 SLAC 6 SLAC 6 SLAC 6
HER 12-3 SLAC 1 SLAC 1 SLAC 1 SLAC 1 SLAC 1 SLAC 1 SLAC 1 SLAC 1
HER 12-4 N/A N/A N/A N/A N/A SLAC 10 SLAC 10 SLAC 10
HER 12-5 Philips 1 Philips 1 Philips 1 Philips 1 SLAC 7 SLAC 7 SLAC 7 SLAC 7
HER 12-6 Philips 8 Philips 5 SLAC 2 SLAC 2 SLAC 2 SLAC 2 SLAC 2 SLAC 2
Power Limited
Installation
Shutdowns
Run 5A Run 5B Run 6
SLAC Tubes
NOW
Vojtech Pacak, PEP-II MAC Review, January 18-20 200611
5) PEP-II RF Station Installation
HER Presently
Oct 2006 LER Presently
Oct 2006
4-1 2 2 4-2 2 2
4-6 n/a 2 4-3 2 2
8-1 4 4 4-4 2 2
8-3 4 4 4-5 2 2
8-5 4 4
12-1 2 2
12-2 2 2
12-3 4 2
12-4 n/a 2
12-5 2 2
12-6 2 2
Install2006
shutdown
Total Kly/Cav 9/26 11/28 4/8 4/8
Vojtech Pacak, PEP-II MAC Review, January 18-20 200612
5) RF Stations Upgrades• Two New RF stations
– HER10, new station 12-4, split 12-3. shutdown 2006– HER11, new station 4-6. shutdown 2006
• Manufacturing/Delivery - major parts– Resonators.
• Manufacturing under process at ACCEL– Expected delivery end of May 2006– Assembly and testing at SLAC May – July 2006
– Klystrons.• SLAC #10 and Philips #4
– Expected delivery May – August 2006
– Circulators.• On site
– Waveguides, Loads.• Partially Ordered
– Expected delivery end of May 2006
– HVPS and SCR’s stacks.• Ordered
– Expected delivery March 2006
Vojtech Pacak, PEP-II MAC Review, January 18-20 200613
6) Conclusions
For Run 5:
• RF system works in general reliably this run!• RF abort rate averaged 3/day, compared to 2.9/day for Run 4.• Currently 3 power limited klystrons in the HER, 1 in LER.• ~55% of all RF aborts caused by:
– Klystron arcs in LER 4-3 and HER 12-6.• 4-3 operates with limited voltage, replaced klystron in 12-6
– Arcing or vacuum trips of cavity #1/2 in HER 8-1 and 12-1 stations.• Lower cavity voltage when arcing may cause the problem
– HVPS. • Ongoing investigation of SCR’s failures and region power dips
• 3 new SLAC tubes plus 2 repaired Philips klystrons by mid of 2006.• Improved situation with spare klystrons.
• Starting in March, new klystron delivery in every ~ 5 weeks.
For Run 6:• Two new HER RF stations, #10-(HR12-3 split) and #11-(2-cavity HR4-6).• Up to 3 more new/repaired klystrons ready for installation in LER.
Vojtech Pacak, PEP-II MAC Review, January 18-20 200614
Acknowledgements
• To all members of the PEP-II RF Systems Taskforce from the following SLAC departments:– ARD-A LFB Systems– ESD LLRF and Software Systems– Klystron High Power RF and TFB Systems– PCD HVPS Systems
• Specific thanks to Heinz Schwartz, Alan Hill, Chris Pearson, Dan Van Winkle and Marc Larrus for their input to this presentation.
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