Injection and Dump System

W. Bartmann, M.J. Barnes, C. Bracco, E. Carlier, B. Goddard, V. Kain, M. Meddahi, V. Mertens, J. Uythoven, L. Drosdal

LHC Beam Operation Workshop

Outline LBDS:

2010/2011 performance TCDQ induced beam dumps and HW problems

Injection System: 2010/2011 performance MKI problems:

Flashover Erratic Vacuum Temperature

Other observations XPOC IQC Summary

Evian, 12/12/2011

LHC Beam Operation Workshop

2010 LBDS

Evian, 12/12/2011

Asynchronous beam dump, during energy scan without beam (due to spark on the outside of the gate turn-off GTO thyristor): 1 at 5 TeV 2 at 7 TeV

5 internal triggers: 1 due to BETS and 4 due to vacuum interlocks on the MKB for B2 (FALSE vacuum pressure reading)

1 Asynchronous beam dump with beam: Failure of a single power driver in one Trigger Fan-Out unit (TFO) LBDS self-

triggering of two generators for Beam 1: MKD C and D IPOC fault and XPOC fault

Subsequent retriggering of remaining 13 generators worked perfectly

2 beam dumps induced by TCDQ faults: timing event sent TCDQ and thresholds to 3.5 TeV setting (< 4 s at 450 GeV)

beam then was injected and dumped due to losses in point 6. beam 1 dumped due to a glitch in position readings (resolver read injection

values) at end of ramp (out of thresholds).

Evian 2010

LHC Beam Operation Workshop

2011 LBDS

Evian, 12/12/2011

No asynchronous beam dump 7 internal triggers with beam (BETS, PLC, vacuum pump off in

the dump line …) Internal triggers without beam due to:

TSU new firmware back to 2010 version PXI failures N.I. digitizer fuses replaced on all boards GTO switches

10 Beam dumps induced by TCDQ: Retraction TCSG/TCDQ SIS interlock (90 m b* ALPHA roman pots

setup, tight collimators settings) TCDQ at wrong position when injecting pilot (after previous test to check

TCDQ offset) SIS interlock on beam position at TCDQ during ramp and at flattop 2 energy interlocks at the beginning of the ramp (glitch in energy limit)

relaxed limits Position interlock at the end of the ramp (server problem)

BPMS interlock still reading wrong number of bunches, HW interlock based on another signal so we can leave with that

Mainly during ramp down, 2-3 h access required

LHC Beam Operation Workshop

Other problems with TCDQ

Evian, 12/12/2011

Problems with running TCDQ sequence, loading settings and thresholds generally solved repeating sequence and/or running ramp (in some cases the beam had to be dumped)

Mechanical offset: Measured on 10/03/2011 and compensated by adding:

B1: -0.25 mm for all settings B2: +0.5 mm at 3.5 TeV setting and +1 mm at 450 GeV

B2 TCDQ offset “Corrected” during TS previously defined settings non more valid TCDQ offset put back but in the wrong direction offset had to be re-measured (2 hours) new settings B2: -0.6 mm for all settings

10/03/2011 13/07/2011

LHC Beam Operation Workshop

2010 Injection System

Evian, 12/12/2011

Chamonix 2011

Abort Gap Keeper (AGK) prevented MKI from firing Train of 32 bunches dumped on upper TDI jaw showers to ALICE

Losses in ALICE in agreement with simulations (further benchmarking data from TDI grazing tests) ALICE ready for 288 bunches on TDI

LHCb, only grazing tests with TDI No indication of limits on

injected intensity: 288 bunches OK! BUT TDI must be correctly set up!!

LHC Beam Operation Workshop

MKI Flashover 18/04/2011

Evian, 12/12/2011

Injection of 2 × 36 bunches spaced by 2.2 ms Breakdown after ~2 ms All 36b of 2nd batch were kicked with 110-125% nominal MKI deflection

Beam was on LOWER TDI jaw and over-kicked, i.e. breakdown in second half of magnet (LHCb signals support this)

Nearly all p+ of the 36b impacted on the TDI/TCLIB (grazing) 11 magnets quenched

B1 1

2bB2

12b

B1 7

2bB2

72b

B1 7

2bB2

72b

B1 7

2bB2

72b

B1 is causing the vacuum pressure rise in the B2 kicker – this is not new

MKI HW vacuum interlock reduced from 5e-8 mbar to 2e-8 mbar

New SIS to prevent injection if MKI pressure >2e-9 mbar for 50 ns beam (temporary >2.5e-9 mbar for scrubbing with 25 ns beam)

Checked carefully TDI angular alignments in IR2 and IR8

TCLI openings TCLIB to 8.3 s New Fixed Display in CCC with MKI pressures Solenoids between MKI and Q4/A5 switched ON

ALICE Polarity

B1 left [mrad]

B1 right [mrad]

B2 left [mrad]

B2 right [mrad]

Old -70 -750 -190 -110New +86 -1035 -190 -110

LHC Beam Operation Workshop

MKI Vacuum Activity

Evian, 12/12/2011

To avoid possible vacuum/breakdown problems with the MKIs, solenoids:

ON during normal operation OFF during scrubbing provided pressure

does not become too high (respect SIS injection interlock)

In future, possible to include a interlock (under study)

Solenoid switched off

Intensity

EnergyVacuum in IR2 Energy

Intensity

Vacuum in IR8

Vacuum MKI Beam 1

Vacuum MKI Beam 2

M.J. Barnes

dtP

2E-9

2E-9

LHC Beam Operation Workshop

MKI Erratics on 28/7/2011

Evian, 12/12/2011

4.5µs

2µs

MSC erratic

Current in kicker magnet

0

5000

10000

15000

20000

25000

30000

35000

40000

45000

50000

55000

Appr

ox P

FN V

olta

ge

Sample Number

MKI2. 28 July 2011, 6:03:09 PM

7/28/2011 6:03:09 PM PFN1

7/28/2011 6:03:09 PM PFN2

7/28/2011 6:03:09 PM PFN3

7/28/2011 6:03:09 PM PFN4

Erratic turn-on of MKI2 MSC

16:30:43

18:03:09

Interlocks detected an MSC erratic and correctly triggered MS’s and DS’s of system (within 2µs), emptying PFN via both ends. Hence kicker-C pulsed for 6.5ms and 3 other kicker magnets pulsed for up to 4.5µs, emptying PFNs of energy. Circulating beam was not in IP2 and therefore not disturbed. Batch was extracted from SPS but saw no kick at MKI2 (current already back to zero in all magnets) and went straight into the TDI upper jaw.

Erratic of MKI2 MSC at 33kV during resonant charging – sending current to one of the four kicker magnets Interlocks did NOT detect erratic of MS3: hence no immediate action was taken to turn-on other thyratrons full 9 ms PFN pulse length to kicker C. Failure ~500µs into charging process: extraction from SPS correctly inhibited;Circulating beam was swept over aperture and grazed TDI (~17% of normal kick) for ~8-9µs 150-190 bunches

LHC Beam Operation Workshop

MKI Erratics on 28/7/2011

Evian, 12/12/2011

4.5µs

2µs

Current in kicker magnet

0

5000

10000

15000

20000

25000

30000

35000

40000

45000

50000

55000

Appr

ox P

FN V

olta

ge

Sample Number

MKI2. 28 July 2011, 6:03:09 PM

7/28/2011 6:03:09 PM PFN1

7/28/2011 6:03:09 PM PFN2

7/28/2011 6:03:09 PM PFN3

7/28/2011 6:03:09 PM PFN4

Erratic turn-on of MKI2 MSC

16:30:43

18:03:09

Interlocks detected an MSC erratic and correctly triggered MS’s and DS’s of system (within 2µs), emptying PFN via both ends. Hence kicker-C pulsed for 6.5ms and 3 other kicker magnets pulsed for up to 4.5µs, emptying PFNs of energy. Circulating beam was not in IP2 and therefore not disturbed. Batch was extracted from SPS but saw no kick at MKI2 (current already back to zero in all magnets) and went straight into the TDI upper jaw.

Erratic of MKI2 MSC at 33kV during resonant charging – sending current to one of the four kicker magnets Interlocks did NOT detect erratic of MS3: hence no immediate action was taken to turn-on other thyratrons full 9 ms PFN pulse length to kicker C. Failure ~500µs into charging process: extraction from SPS correctly inhibited;Circulating beam was swept over aperture and grazed TDI (~17% of normal kick) for ~8-9µs 150-190 bunches

Hardware problem faulty

components exchanged +

additional diagnostic + faster

detection electronics with

lower voltage threshold

MSC erratic

LHC Beam Operation Workshop

MKI Erratic Effects

Evian, 12/12/2011

173 bunches - 2.15e13 p+ lost (not dumped) 3 magnets quenched ALICE:

The values of BCM threshold for beam background were exceeded: 16:30 - 80 times 18:03 - 3559 times

9 /17 sub-detectors were affected during second erratic event All subsystems except Silicon Drift Detector (SDD) recovered using standard

procedures 20% of modules with good drift speed from injector on layer 3 and 60% on layer

4 (permanent effect)intensity and #bunches will still increase

(slightly) worse impact parameter possible

Up to a factor of 2-4 higher losses might occur in future years!OK for machine, but main concern is safety for ALICE/LHCb.

Detectors must be off during injection! M.Lechman

LHC Beam Operation Workshop

0

0.5

1

1.5

2

2.5

3

3.5

4

85 90 95 100 105 110 115 120 125 130 135 140 145

Indu

ctan

ce (μ

H)

Average of Magnet Input Face and Output Face Temperature During Cool down (˚C)

33 cells * 101nH/cell

106˚C

Magnet in vacuum tank; tank at atmospheric pressure; no bake-out jacket.

MKI Temperature Interlock

Evian, 12/12/2011

Ferrite Heating Measurements in Clean Room:Curie point of ferrite corresponds to 106 ˚C measured on ground plates

M.J. Barnes

y = 7.39E-10x + 2.04E-07R² = 9.98E-01

y = 3.79E-09x + 3.25E-07R² = 1.00E+00

6.00E-07

6.10E-07

6.20E-07

6.30E-07

6.40E-07

6.50E-07

6.60E-07

6.70E-07

6.80E-07

6.90E-07

7.00E-07

7.10E-07

2.580E-07

2.600E-07

2.620E-07

2.640E-07

2.660E-07

2.680E-07

2.700E-07

2.720E-07

2.740E-07

2.760E-07

2.780E-07

2.800E-0775 77.5

80 82.5

85 87.5

90 92.5

95 97.5

100

50%

Del

ay (s

)

TMR

Volta

ge R

ise T

ime

(s)

Magnet Inductance Scale Value (%)

Predicted 5% to 95% rise-time versus magnet Inductance

RISE_TIMEC(V(MagOut)*50kV/250,1.25k,23.75kV)

XVALUE_AT_YV(V(MagOut)*50k/250,12.5k)-XVALUE_AT_YV(V(MagIn)*50k/250,12.5k)

Magnet inductance decreases with reducing ferrite permeability magnet strength decrease Rise-time decreases with reducing inductance and/or capacitance Delay decreases with reducing inductance and/or capacitance

Softstart measure rise-time indirect measurement of inductance (temperature)

During Xmas stop: new diagnostic to measure delay (more sensitive)

LHC Beam Operation Workshop

MKI Temperature Interlock

Evian, 12/12/2011

y = -1.325E-05x + 7.069E-01R² = 1.501E-02

y = -7.324E-05x + 7.041E-01R² = 7.792E-01

y = -2.065E-05x + 6.970E-01R² = 3.514E-01

y = -3.563E-05x + 7.004E-01R² = 8.375E-01

y = -2.828E-04x + 7.153E-01R² = 6.809E-01

0.695

0.696

0.697

0.698

0.699

0.7

0.701

0.702

0.703

0.704

0.705

0.706

0.707

0.708

0.709

20.00 25.00 30.00 35.00 40.00 45.00 50.00 55.00 60.00 65.00 70.00Ri

se T

ime

(µs)

MKI8 Measured Temperature (˚C)

MKI.UA87.IPOC.?B2:T_RISETIME (October 2011)

MKI.UA87.IPOC.AB2:T_RISETIME

MKI.UA87.IPOC.BB2:T_RISETIME

MKI.UA87.IPOC.CB2:T_RISETIME

MKI.UA87.IPOC.DB2:T_RISETIME

SIS interlock presently 62 ˚C (originally 55 ˚C ) cannot be further increased !MKI Temperature is < 68 ˚C and lags real temperature (ferrite thermal capacity) Softstart: OK injection

not Ok wait for MKI cooling

M.J. Barnes

Capacitance Inductance

LHC Beam Operation Workshop

Other Problems Related to Injection System

Evian, 12/12/2011

UFOs at MKI several beam dumps at the beginning of the run (T. Baer’s talk) Problems with kicker delay (ions run) Beam on TDI (32 and 144 bunches) due to operational error (AGK inhibited MKI

from pulsing as it should) Vacuum pressure increase at TDI in IR2 and IR8 when at parking position (±20

mm) High background in ALICE (shielding?) new parking position ±55 mm (B. Salvant’s talk)

TDI.4L2 controls problem: required setting different from

measured motor position Noise in the measurement of jaw

positions gap opening outside limits TDI.4L2 gap interlocks changed by 100mm to avoid interlocks due to drift of the position reading triggered by electromagnetic noise

Wrong settings of injection protection collimators (TCDI, TCLI and TDI): Association with “bad” beam process (during MD) Solution: injection protection collimators on an independent beam process

S. Redaelli

LHC Beam Operation Workshop

XPOC

Evian, 12/12/2011

Encountered problems Data missing (BLM, BCT, BSRA, Vacuum) Wrong filling patterns and faults on MKB waveforms

new release and filters to reduce noise due to high bunch intensities (not completely solved)

Problems with inject and dump (late BLM data) new BIS interface card installed

Acknowledgment logic: EIC-MPS can reset errors in Context and BLM modules LBDS-EXPERT can reset all modules. No evident reason to change it in 2012!

LHC Beam Operation Workshop

IQC

Evian, 12/12/2011

New features: Injection oscillations max/rms vs bunch number; Playback: actual or of the date reference thresholds

LHC Beam Operation Workshop

IQC

Evian, 12/12/2011

New features: Injection oscillations max/rms vs bunch number; Playback: actual or of the date reference thresholds

Problems: Injection of 144 bunches not seen by the IQC and the injection

sequencer danger of overinjection (server communication problem?)

Missing MKI data and BCT from TL

Acknowledgment and Improvements: Phase error integration Limits at TL BPM (MD to define them) easier steering Clear warning level at critical BLMs depending on number of bunches

injected (i.e. MSI ≥ 5% with 12 bunches steering needed ) Injection oscillations interlock still maskable in 2012?

LHC Beam Operation Workshop

Summary 1/2

Evian, 12/12/2011

Equipment Problems in 2011 Applied Solution 2012 Operation

LBDS Internal triggers Electronics, faulty components exchanged

Ok, new power supplies. Testing time during machine checkout for new HW/SW/FW

No async. dump Ok

TCDQ Load thresholds/settings, energy limits and position interlocks

Repeat sequence Ok, b* interlock +new potentiometer electronic more precise position reading

Mechanical Offset Compensation with beam based alignment

Ok

MKI Flashover

SIS interlock to inhibit injection in case of vacuum exceeding thresholds

Ok if injection protection collimators correctly set up and detectors off during injection

Erratic Faulty components replaced + diagnostic + faster electronics with lower voltage threshold

Ok if injection protection collimators correctly set up and detectors off during injection

Temperature SIS at 62°C + softstart to measure rise-time (inductance)

Ok if T does not increase further since close to Curie limit.New diagnostic to measure delay

Vacuum HW interlock + MKI cond.+ e-cloud solenoids

Ok but waiting time between injections, conditioning (25 ns more critical)

LHC Beam Operation Workshop

Summary 2/2

Evian, 12/12/2011

Equipment Problems in 2011 Applied Solution 2012 Operation

TDI Angular offset Compensation with beam based alignment

Ok

Vacuum and ALICE background

Parking position to ±55mm

Ok

Controls (LVDT noise) Relaxed gap interlock Ok, if noise not worse

TDI/TCLI/TCDI Association to “bad” beam process wrong position

Not Ok, Separate beam process needed

XPOC Missing data, faults New release, filters, cards….

Ok, stronger filters + BI data collection improvements (directly into PM system)

IQC Missing data, injection not detected

New release Ok but needs to become clearer (closer to operation, easier steering). Risk of 144 bunches overinjeciton must be eliminated

Ready for 2012 operation but: Dedicate enough time w/wo beam to properly test components (new electronics, SW, FW....) and set up (collimators, IQC references for steering...) Respect safety instructions (Experiments off during injection, MKI vacuum and temperature interlocks)

Safe operation and reduce downtime!!!

Backup

LHC Beam Operation Workshop

TCDQ Upgrade (LS1)

Evian, 12/12/2011

Upgrades for IR6 dump protection TCDQ upgrade for robustness: graded Carbon Composite (1.4g/cc and

1.65 g/cc), absorber length 6m -> 9m (1 more module) TCDQ controls: collimation stepping motor system and low-level (to be

decided) New improved TCDQ bellows TCSG with BPM buttons Additional TCLA – to be decided after FLUKA studies Phase advance MKD-TCDQ exactly 90° to reduce # of escaping particles

rematch the optics (R. Bruce’s talk)

T. Kramer

LHC Beam Operation Workshop

Two More Erratics…….

Evian, 12/12/2011

16:30:43Two more erratics happened during softstart on 30/07/2011

Hardware problem Actions:

• Replaced MS3– damaged current regulator on bias board • Remote current monitoring added• New G1 trigger cards installed• Damaged thyratron switch replaced• Fiber optic read-back to better monitor thyratron and bias-board G1 current ??

Diagnostics added

Power supply and crate for MS3 heater/reservoir replaced.

Trigger units for MS3 replaced.