pep-ii rf system status and upgrades

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


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


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*


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?


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


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


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


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


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


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 12-1 Philips 6 Philips 6 Philips 6 SLAC 8 SLAC 8 SLAC 8 SLAC 8 SLAC 8



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


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


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


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.


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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