RF Commissioning in Point 4

Hardware Commissioning:

• ACS RF System - Power Systems• ACS Cavities : Sector 4-5 • ACS Cavities : Sector 3-4• ADT Power and Feedback Systems Commissioning

Preparation for beam:

• RF Synchronization• Beam Controls - ACS and ADT• Diagnostics and other Facilities

Summary/Conclusions

E. CiapalaOn behalf of the AB-RF Group

LHC MAC June 08 – RF commissioning in Point 4 1

2

ACS/ADT racks(driver amplifiers,PLC controls, fast interlocks)

Beam 1

Beam 2

8 Dedicated Pick-ups BPMC @ Q7L, Q7R, Q9L, Q9R

The RF Systems Underground at Point 4

APW Wideband Monitors3 left/3 right of IP4

Cavity feedback racks in Faraday cages

SC Cavity Cryomodules ( each with 4 single cell cavities)

16 Klystrons400MHz, 300kW

IP4

ADT Transverse Damper kickers- 4 modules left/4 right of

IP4+ space for 2 more modules

(upgrade)LHC MAC June 08 - RF Commissioning in Point 4

3

ACS Power - Klystron Collector cooling modifications

Klystron ‘boilers’ modified: Bad water cooling of collector (SM18 klystron vacuum leak)Hypervapotron mode

• Requires homogenous water flowModification agreed with manufacturer:

• Dismantling in-situ in UX45, klystron in horizontal positionModification of all 16 klystrons & re-installation completed before start of

cavity testing November 2007.

A relatively straightforward operation

Overheating of collector

Klystrons in horizontal position in UX45 for modifications

Klystrons in normal vertical position in UX45

LHC MAC June 08 - RF Commissioning in Point 4

4

ACS Power Systems Commissioning

High voltage commissioning – No RF:

Power convertor tests (AB/PO) Controls, interlocks Operation: 10kV UX45 services, cooling (air, water) DCCT Klystron equipment, focus supplies Crowbar operation (with spark gap) Operation: 58kV Klystron modulator control crowbar (ext. trigger @ 62kV) Klystron heaters current settings

Completed for all four systems

power converter

HV switch

mod 1 mod 2 mod 3 mod 4 thyratron 4uF

kly

circ

cav

kly

circ

cav

kly

circ

cav

kly

circ

cav

short circuit

Group of four Klystrons fed by one Power Converter.

Common crowbar, one tetrode modulator per klystron.Housed in Four HV Bunkers

Modulator

Crowbar

HV Bunker

LHC MAC June 08 - RF Commissioning n Point 4

5

ACS Power Systems Commissioning - RF into Waveguide Short

1) Preliminary • RF interlocks, Klystron protection (Wattchers)• RF calibration (Power Meters, directional Couplers)• RF pre-amplifier levels• Circulator temperature control unit set-up

2) 300 kW RF power tests and calibration: Check DC Power, Collector Power, RF Power,

3) Measure klystron saturation curves and set up clamping

RF LOGBOOK: \\cern.ch\dfs\Departments\AB\Groups\RF\Machines\LHC\LowLevel\Commissioning\CavController\CavSettingUp\B1\CAV2B1

LHC MAC June 08 - RF Commissioning in Point 4

6

4.5 KRefrigerator

QUI

NRV

SC Cavities

Coupler cooling cct.

HP

MP

LP

WarmCompressor

Station

ColdBox

?

C (4.5 K; 3.0 bar)D (20 K; 1.3 bar)

Warm recovery line (≤300 K; ≤1.1 bar)

Safety System

Safety System

ACS Cavity Commissioning – Cryogenics for RF cavities

LHC MAC June 08 - RF Commissioning in Point 4

Cavityies He tanks & circuits are low pressure systems, <2 bar but fed from magnet QRL

Concern: Overpressure in D-Line on multiple magnet quench (<20 bar estimated)Rely on: Process control, auto blocking outlet valve, non-return valve (NRV) in D-Line.Safety study: (SC, AT-CR & AB-RF ) Analysis of all risk situations (~10): EDMS 880723 => Recommendations => 1.5/1.8/2.1 release valves/rupture discs, procedures.Warm Recovery Line (WRL) installed to recuperate static losses when D-Line closed, to avoid release valves opening. Late decision. Extra outlet dome on module, cryo lines, heaters etc.

Courtesy S. Claudet

7

ACS Cavity Commissioning – Cool-down and first tests Sector 4-5

C8.B1

C7.B1

C6.B1

C5.B1

C4.B2

C3.B2

C2.B2

C1.B2

400.55

400.60

400.65

400.70

400.75

400.80

400.85

400.90

400.95

401.00

0%

100%

•Pressure test 2.1 bar done all modules (incl. Sector 3-4) Mid 2007

•Start cooling 2 modules (sector 4-5) on Nov 20th 2007•Careful setting up of cryogenic processes and safety systems•2 modules cold on Nov 22nd - 24 hours to stabilize

• Low-Power tests, Generator connected to w/g transition piece, measure resonant frequency and Qext

•Check of Tuning Range on 8 cavities Sector 4-5 (frf = 400.790 MHz)

Check of Qext on variable couplers

0 10 20 30 40 50 60

10000

60000

110000

160000

210000

260000

LHC3 Q FACTOR 30.11.2007

CAV ACAV BCAV CCAV D

Coupler position in [mm]

Q f

acto

r

0 10 20 30 40 50 60

10000

60000

110000

160000

210000

260000

LHC2 Q FACTOR 30.11.2007

CAV ACAV BCAV CCAV DACS FREQ

Coupler position in [mm]

Q f

acto

r

LHC MAC June 08 - RF iCommissioning n Point 4

8

ACS – Low Level RF systems – Cavity Controllers in UX45 Faraday Cages

Cavity Controller

•One system per cavity (in 2 VME crates)•Located in two Faraday cages in the UX45 cavern•Control phase and amplitude of cavity voltage.

Take reference from AB-PO standard function generators interfaced via serial link into cavity contoller.

• Minimize disturbances from•HT ripples from Power Converters: 1 % HT ripple -> 8.4

degrees @ 400.8 MHz•Transient Beam loading•Keep demanded klystron power reasonable and avoid

saturation (300 kW max). •Largely digital implementation•Operates at the bunch rate (40 Msps)

Modules/Functions:

Tuner Loop: Keeps cavity at optimum tuning to minimize klystron power (Also ‘half detuning ‘ to keep the power flat across beam segments and gaps)RF Feedback Loop: Reduces the cavity impedance at the fundamental (by 20 linear for Q=20000, by 180 at Q = 180000). Precision of RF voltage, transient beam loading and longitudinal stability1-T Feedback: Adds factor 10 reduction on the revolution frequency side-bands. (Transient beam loading + longitudinal stability)Klystron Polar Loop: Compensates for the klystron gain/phase changes. (HT drifts and ripples, 50 Hz components and multiple).Set Point: Voltage & Phase control, Interface to the function generator, can also customize the voltage reference for each bunch, phase and amplitude. Conditioning: Automatic conditioning system integrated. with local synthesizer. Also used for open loop set-upLongitudinal damper: Damps the injection phase and momentum errors, batch by batch Acts on 400 MHz cavities. (Postponed)

Cavity Controllers installed in FC B for Sector 3-4 cavities

LHC MAC June 08 - RF Commissioning in Point 4

9

ACS Cavity Commissioning – Conditioning (Power Processing)

•Processing simultaneously cavity and power coupler, fast gain loop acting on vacuum activity•Use same strategy as for initial conditioning in SM18 test stand:

Initial pulsing with slow rise-fall envelope, increasing voltage, increasing pulse width then DC, at all coupler positions. Keep low vacuum set limits throughout.

Conditioning time as expected. Quickly reached 2 MV/cavity (Nominal 5.5 MV/m) in pulsed mode

Then ~ 2weeks overall net time to get to CW operation at 300 kW

•Process handled by local DDS in cavity controller,

•Full remote control via network,

•Run all cavities simultaneously => time saving

Radiation measurements:

•Peak value: few mSv/h close to the cavities (8 cavities running)

Might get higher radiation above 2MV…

•No radiation measured nor in UX45 nor outside the RF zone

LHC MAC June 08 - RF Commissioning in Point 4

10LHC MAC June 08 - RF Commissioning in Point 4

ACS Cavity Controller Commissioning in UX45 – Cavities Cold

Some time taken to set up signal levels and calibrate signal distribution system

Test results matched those in SM18 tests on a single cavity:

Tuner Loop: good stability, ~ 1 step correction per second (25 Hz) as expected

RF feedback: Loop delay as expected 600 – 650 ns, Closed Loop response as expected: 700 kHz 2-sided BW

Q ~ 600, R reduced from 2.7 Mohm (Q=60000) to 27 kohm

Closed Loop, Cav 7 B1, Q=60000, O.L. gain ~ 100 Overall open loop freq responses & Group delay

11

ACS Cavity Controller Commissioning in UX45 – Cavities Cold

Klystron ‘Polar’ Loop: Performance as expected from SM18 tests & Matlab simulations. Adjusted response of the Klystron Loop (~15 us) with the RF

feedback loop ON (time response ~ 1 us)

HT Cav phase Cav Pwr Gain Cntrl TP Phase Cntrl TP57.6 kV -166.3 deg 0.52 dBm 207 mV 93 mV55.7 kV -166.3 deg 0.52 dBm 201 mV 137 mV53.7 kV -166.3 deg 0.52 dBm 193.3 mV 189 mV51.8 kV -166.3 deg 0.52 dBm 186 mV 242 mV49.9 kV -166.3 deg 0.52 dBm 184 mV -300 mV to +300 mV47.9 kV -166.3 deg 0.52 dBm 187 mV -242 mV46 kV -166.3 deg 0.52 dBm 189 mV

Polar Loop compensates klystron gain and phase shifts with varying HV (without loop 8.4 degree RF per percent HV)

Cav8 B1 PSD of Phase noise Vcav-Ref RF f/b ON and Klystron Loop Open/Closed (~10 dB reduction @600 Hz)

Cav8 B1 PSD of Phase noise Vcav-Ref, RF f/b Open/Closed (~47 dB reduction@600 Hz)

Only managed to completely set up 3 of the eight cavities before Sector 4-5 was warmed up, however progress made on procedures and software will

allow faster completion of other cavities

LHC MAC June 08 - RF Commissioning in Point 4

12

ACS RF Commissioning: Summary

Access system de-bugged. Two systems: main tunnel system and upper UX45 system.

Some delays due to co-activities on equipment in RF zone. Handling of 18kV reset on door forcing, etc..

RAMSES RP monitoring systems tested & validatedPeak value: few mSv/h close to the cavities (8 cavities

conditioning simultaneously)Can expect higher radiation above 2MV, conditioning before

installation (in SM18) was done to 3 MV (8 MV/m)No radiation measured in UX45 nor outside the RF zone

Cryogenics systemClose collaboration with AT-ACR in setting up (important)Availability and reliabilty good..Some initial cryo control issues, (He lost through safety valves

instead of through WRL)Excellent cryogenic regulations (level & pressure) in the modulesSo far no observation of magnet quenches on RF cavities

RF Summary Sector 4-5

5 weeks cold in 2007, then 7 weeks in 2008Low power tests on all 8 cavitiesConditioning to nominal field and full powerSet up of loops on three out of 8 cavities. Need ~ 2weeks to finish the other 5….

Power Tests since Sector 4-5 commissioning Test with all 4 power converters simultaneously

at full power Optimize HV ripple on power converter (600Hz) Test spare power converter Test spare HV cables (surface to tunnel)

RF Commissioning in Sector 3-4….Cryo instrumentation etc. starting nowLow power tests on all 8 cavities NEXT

WEEK…Conditioning to nominal field and full

powerSet up of loops on all 8 cavities.

LHC MAC June 08 - RF Commissioning in Point 4

Sector 3-4cavities cold & ready for RF ~ mid-Juneexpected commissioning time: ~ 6-8 weeks

Sector 4-5cavities cold & ready for RF ~ Julyexpected commissioning time: ~ 2-4 weeks

LHC MAC June 08 - RF Commissioning in Point 4 13

Sector 4-5 Sector 3-4

Hardware Commissioning Status

14

ADT Power Systems Commissioning

LHC MAC June 08 - RF Commissioning in Point 4

9 HV power converters

•Eight installed in SR4, one in 867 tests stand (for tests and as spare)

•One power converter (15kV, 14A dc) drives two power amplifiers, i.e. four tetrodes.

•All tested up to required power (12kV - 2 x 7A) B867, before being installed in SR4

•All tested with DC operational settings (12kV - 2 x 2.5A) in SR4 for several weeks, and with RF applied on the amplifiers

16 Power Amplifiers:

•Tested in B867 tests stand at full DC anode voltage of 12kV, 7A of DC current per amplifier and with 0 dBm signal source.

•Input circuit, amplitude and phase characteristics of all 16 amplifiers were stored in pictures and data files.

•Tests showed similarity of the characteristics of amplifiers with tetrodes of the same type.

15

ADT Power Installation/Commissioning - in Tunnel

LHC MAC June 08 - RF Commissioning in Point 4

•High voltage feeders to kickers (strip connectors) mounted to their supports in the tunnel.

•All kickers were aligned, baked out to (200 degC), and connected to the vacuum chambers

•Water cooling systems were tested (single amplifier and the whole system)

•RF tests were made on individual amplifiers, then with all the amplifiers together

Problems :• 1 HV resistor broken (water leak), repaired and re-

installed, no more fault• 2 HV capacitors burnt, repaired and re-installed.• 1 amplifier shown an over heat of the input socket (not

confirmed with a second test in our tests area, pt100 fault?)

•Still have to finish the RF heat run and the final measurements (planned by end-June)

Controls and Software

Front-end hardware:• PLCs for equipment control• VME Crates for LLRF systems and feedbacks

All front-end software based on FESA

Applications software:• LSA (Control room)• Applications for RF experts and system commissioning

Signal diagnostics accessible via OASIS:• Fast digitizers in Compact PCI crates• Embedded acquisition buffers in digital LLRF hardware

Slow Controls• PLC, FESA classes, specialist applications for power systems, Developed & tested• ACS & ADT slow control systems installed in UX45, tested and fully commissioned locally.• Remote control GUIs, based on Labview and AB/CO ‘Knobs’, operational and extensively used during commissioning.

LLRF controls (Cavity Controller, Beam Control, RF synchro)• Drivers for 30 different VME modules, based on rigorously defined memory map and functionality (streamlined design

environment built up)• Cavity Controller and Synchro front-end software operational; ‘Expert’ GUIs available• Beam Control front-end software implementation in progress

Interface with operational software• Parameter model and settings management defined in LSA; implementation in progress by AB/OP• Full remote control of cavity systems via LSA to be tested after Sector 3-4 commissioning (end June)

LSA operational applications and

setti ngs management

Expert applications LabVIEW/MATLAB

Front Ends PC/Linux/FESA

PLC supervision

Front Ends VME/LynxOS/FESA

RF Low-Level electronics

Front Ends cPCI/Linux/FESAAnalogue signals

acquisition

PLCs Schneider Unity

CMW Middleware

RF power and cavity equipment

Signal observation OASIS

ModbusTCP/IP

LHC MAC June 08 - RF Commissioning in Point 4 16

17

Remote control GUIs, based on Labview and AB/CO ‘Knobs’, operational and extensively used during commissioning.

ACS HV controls, klystron & cavity, Local conditioning DDS control

Web based ACS overall status

Labview applications

Software Applications

LHC MAC June 08 - RF Commissioning in Point 4

18

LLRF - RF Fast Timing and Synchronization

Synchronization of the SPS-LHC RF bunch into bucket transferGeneration of beam synchronous signals: 40 MHz bunch clocks, revolution frequencies, 40 MHz 7TeV reference

injection pulsesTransmission of timing & clocks to the users: BI, BT and Experiments, from SR4 via fibre linksFine-rephasing of the two rings before physics

Locking each ring on a low-noise fixed-frequency synthesizer.

System Comprises 5 VTUs, 3 generators, 30 Fibre optics Tx/Rx Pairs.

Recent Successful Dry-Run test with all users and OP group, including basic software.

DDS1 DDS2F RF Prog 1 F RF Prog 2

WB

sw

itch

WB

sw

itch

Inj. F rev

F injRing 1

Ring 2

Ring 1

Ring 2

Pha

se s

hifte

r

1/(7 h) divider

1/h Divider

RF IN

OUT

1/h DividerRF IN

OUT

SyncOUT

RF IN

Sync

Bucket nbr.

Shi

fted

F in

j to

SP

S

Del

aye

d F

c to

SP

S

SP

S e

xtr.

war

ning

Inj. Pulse generator

RF IN

OUT

Inje

ctio

n pu

lse

Injection VETO

Sync

Ring 1

Ring 2

Ring 2

Ring 1

Next

Shut

Open

Inj. Phase

WB Demux

Inj.

Rin

g 1

Inj.

Rin

g 2

Fiber optic links to AB/BT

Fiber optic links to/from SPS FC

Ring 2

Ring 1

F rev prog1

F rev prog2

Fiber optic links to UX45

VTU

DUAL FREQ PRGM

BUCKET SELECTOR

INJ PULSE GENE

VTUVTU

Programmable delay in the bucket selector selects the LHC bucket for transfer

Module generates pulses sent to the injection kickers

Divider adjusts the relative position of Beam 2 wrt Beam 1

LHC MAC June 08 - RF Commissioning in Point 4

19

ACS (RF System) Beam Control Systems

One system per ring, located on the surface (SR4)Generates Master RF @ 400.8 MHz (VCXO output), phase is adjusted continuously. Update at 11 kHz revolution frequency

Three loops for each beam:Phase Loop locks the Cavity-Sum voltage (8 cav/beam) onto the Beam PU signal in order to minimize the RF phase noise. The loop is switched ON at first injection.Synchro Loop locks the VCXO output on a Frequency-Program DDS. The DDS output frequency is the injection frequency during filling and follows the B field during acceleration. The loop is ON before injection and remains ON all the time in normal operation (until re-phasing before physics when the DDS is replaced by a Synthesizer)Radial Loop to keep the beam centered during acceleration ramp. Can use for commissioning in place of Synchro loop.

R1

Low-levelLoops

Processor

Radial PUFront-end

VCXO

Phase Discri

F RF Prog 1

Radial loop

Phase loop

Synchro loop

DDS1 DDS2

Sync

F1

,P1

F2

,P2

F1 F2

1/h divider

Master F rev

To Ring 1 Cavity Controllers (fibers)

Dual Frequency Program and

Rephasor FPGA

Function Gen. Function Gen.

F RF Prog 2

DUAL FREQUENCY

PRGM

Master F RF

Beam 1

Rad. PU

Beam/Vt phase

RF/Fprog phase

F out

Ra

d P

os.

Fiber Optic TX

BEAM CONTROL

LOOPS MODULE

Radial steering with radial loop

Coarse F1

LF switch

Phase Discri

7 TeV synthesizer

Phase shifter

180 deg hybrid

a b

BEAM POS

MODULE

FPGA

AD

C

SYNCHROMODULE

Ib RF Summing Network

Vt

Phase PU

AD

C

CORDIC (+ AGC?)

Bunch/RF phase

CORDIC (+ AGC?)

Vt/RF phase

Phase Difference

and Averaging

BEAM PHASE

MODULE

AD

C

Cavities

Analog I/Q demod

Analog I/Q demod

Master FrfMaster Frf

AD

C

AD

C

Delay adjust

Function Gen.

fsync

fphase

Injection frequency, injection phase and stable phase will be adjusted by observing these two signals

A function sets the RF frequency on the injection plateau and through the ramp

The VCXO generates the RF sent to the Cavity Controllers

This synthesizer replaces the frequency program during physics

Critical Modules: Status -•Beam Phase - in final

development•Dual frequency program

– firmware testing•Beam Position –

firmware testing

System Test - with VCXO, Beam Control

loops, Synchro modules undergoing measurements in Lab.

LHC MAC June 08 - RF Commissioning in Point 4

20LHC MAC June 08 - RF Commissioning in Point 4

Q9

ADC

FPGA

...

...

SERDES

...

...

Q7

ADC

SERDES

SERDES

SERDES

SERDES

FPGA

Xilinx Altera

Q

I

fc = 40 MHz

fc = 40 MHz

ADC

ADCQ

I

fc = 40 MHz

fc = 40 MHz

DAC

ADC

FPGA

SERDES

ADC

SERDES

SERDES

SERDES

SERDES

FPGA

Xilinx Altera

Q

I

fc = 40 MHz

fc = 40 MHz

ADC

ADCQ

I

fc = 40 MHz

fc = 40 MHz

DAC

ΔxQ7

ΔxQ7

ΔxQ9

ΔxQ9

Δx

Δx

400.8 MHz

180º

180º

Coaxial Transmission LinesAndrew HELIAX

7/8" Dielectric Foam

length ~ 650mlength ~ 450m

Macom H-92-2000 MHz

Comb Filter400.8 MHz

Beam position VME moduleProduces normalized beam position digitally at 40 MHzSeries hardware completedFirmware developmentf

Signal processing VME moduleDSPU (“Damper Loop”)Produces vector sum of two PU signalsProvides notch filter at n * Frev, individual tof compensation for each module, loop gain adjust (via op DAC)Based on ACS 1T-FB moduleProto tested, series hardware being assembles, then firmwareSEC

commission in A3

commission in A4

ADT Signal Processing Systems (SR4 Surface)

400MHz BP filters

Gbit SerDes link

21

OptionalNot applicable

System Item Hard-ware

Firm-ware

Drivers FESA Expert App.SW

Comments

Cavity Controller RF Modulator/Klystron polar loopCavity Controller Switch/protection moduleCavity Controller RF feedbackCavity Controller Setpoint moduleCavity Controller Clock generationCavity Controller Clock distributionCavity Controller Analogue demodulatorCavity Controller 1 turn feedback Not essential for startupCavity Controller Conditioning DDSCavity Controller Tuner RF Front endCavity Controller Tuner ControlADT Low level Transverse feedback Minimum functionalityADT Low level ADT radial position acquisition Minimum functionalityAll Crate management module Needed as soon as possibleRF Synchro Trigger unitRF Synchro Injection pulse generatorRF Synchro Dual wideband switchRF Synchro Dual wideband demuxRF Synchro 400 MHz phase shifter Minimum functionalityRF Synchro Optical Tx analog Passive (no control)RF Synchro Optical Rx analog Passive (no control)RF Synchro Optical Tx digital Passive (no control)RF Synchro Optical Rx digital Passive (no control)RF Synchro Synchro Loop (Phase Synchro) Identical to SPS moduleBeam control Frequency Program DDS Similar to conditioning DDSBeam control VCXOBeam control Beam phase measurementBeam control Beam position measurementBeam control Low level loops DSPBeam control LL Loops InterfaceBeam control Beam parameters DSP Postponed 2009Beam control Longitudinal feedback Postponed 2009ACS/ADT Interlock timestamping Not essentialACS Power PLC controlsACS High-level logic & interface to LSAADT Power PLC controlsADT Signal distribution switching RabbitADT High-level logic & interface to LSAACS Automatic conditioning systemBeam Obs Signal distribution switching RabbitBeam Obs Peak detector Minimum functionalityBeam Obs Detected signals (100MS/s) Minimum functionalityBeam Obs Injection MR (8GS/s) Minimum functionalityBeam Obs Bunch length measurement (8GS/s) Minimum functionalitySPS Rephasing Test MD June 2008SPS Ions acceleration Postponed 2009

Not yet startedIn progressCompleted

LLRF Systems – Electronics Modules and Software Development Status

LHC MAC June 08 - RF Commissioning in Point 4

22

APWs and Diagnostics

Two Wideband Longitudinal Monitors per beam• One per beam to surface SR4, beam control system• One to local racks on cryo side of RUX45 tunnel - observation• Multiplexers and CPCi acquisition crates in place in UX45.• ‘Mountain range’ display & bunch length/profile measurements

Software development in progress :

Essential diagnostics for beam commissioning!

LHC MAC June 08 - RF Commissioning in Point 4

Attenuator hardware

PU construction

Installed in tunnel

Triggering acquisition @ 8 Gs/sPeak detection 250Ms/s

23

Conclusions – Remaining Commissioning and Beam Preparation

Hardware Commissioning - Status and Remaining work

• ADT and ACS power systems fully set up, with all required facilities in place. Heat run of damper power systems to be done.• Sector 4-5 cavities conditioned to nominal voltage and power. Cavity controller loops set up on 3

cavities. 5 cavities still to complete, as soon as sector is cold• Sector 3-4 cavites; He tests (starting now) Low Power measurements, Conditioning and cavity

controller set-up as soon as possible• Check of function generators and software to complete (“vertical slice”)

Preparation for Beam

•RF synchro in place – clocks and timing now going to all users•ACS Beam control systems in advanced state but some items critical.•ADT electronics in test.•Software for beam control also critical, but basic functionality will be available for this run •Procedures for beam commissioning well defined.•Longitudinal Diagnostics in good shape to commission and study first beams….

LHC MAC June 08 - RF Commissioning in Point 4

LHC MAC June 08 - RF Commissioning in Point 4 24

Additional slides

LHC MAC June 08 - RF Commissioning at Point 4 25

A1, First Turn Pilot: Inject pilot and center first turn with RF OFFAdjust front end gains to see PU signals, Label bucketsPrepare injection frequency and bunch timing, injection timing, beam dump,

experiment clocks, cavity initial phasing

Beam Commissioning – ACS 400 MHz RF system

A2 Capture and Circulating Pilot at Injection energy.Commission phase loop and synchro loop. RF ON/OFfCaptureCheck cavity phasingAdjust relative positions of the 2 rings for collisions in IPs (cogging)

A3 to A11, Increasing Intensity to Collision on Flat TopPrecise measurements of lifetime, longitudinal profile Set up radial loopSet up multi-bunch injection, Commission the Filling Pattern maskSet up multi-batch injection, Commission the changing filling pattern mask, & update

in phase loopRamping, with function generators and software facilities, fine tuning of rampOptimization of the RF voltage on the flat topRephasing each ring to the 7 TeV Synthesizer (see diagram slide 15)Fine adjustment of collision point (OP and EXP)

LHC MAC June 08 - RF Commissioning in Point 4 26

A4, [450 GeV] Commissioning Damper Loop Measure de-coherence time with damper offMeasure open loop transfer function (mainly at ~low frequency)Make necessary adjustments (gain, phase, delay), Close damper loopScan gain, phase, delay and measure damping time and stability limitsMeasure beam lifetime as function of damper gainScan injection kicker pulse by moving bunch.

Beam Commissioning – ADT Transverse systems

Phase A1 and A2 First turn and circulating beam (1 to 156 bunches Single batch)Observation of beam at damper pick-ups Q7, Q9 and delay equalization:Verification of signal levels (sum signals, calibrate using orbit system)Delay equalization of damper pick-up signals from Q7 and Q9 (in SR4)Kick calibration:-Excite transverse oscillations (phase A2) in order to check available damper kick strength

A3, [450 GeV commissioning] - passiveCommissioning RF front-end (beam position module) of damper and check optics:Verify RF signals from RFLLCommission analog front-endCommission digitization and frev tagging of bunchCheck phase advance Q7->Q9->damper (both beams and planes) Verify beta functions.

A6, A7 RampCheck abort gap cleaning, test parameters & methodsCheck machine protection, BLM triggering fors low intensity bunch and the damper in anti-

damping. At 7 TeV, Again :

Measure open loop transfer function.Make necessary adjustments (gain, phase, delay), Close loop

Measure open and closed loop transfer functions

27LHC MAC June 08 - RF Commissioning in Point 4

RF feedback alone

Coast at 7 TeV/c with 16 MV, 2.5 eVs (fs0=23 Hz).

Blow-up rate below the 24 h synchrotron radiation damping time.1 ps rms white noise just compensates synchrotron radiation damping. We measure 2.4 10-2 ps rms from DC to frev =11250 Hz .

Crossing the 50 Hz line during ramp: During ~ 1 min, 50 Hz falls inside fs band. Dangerous

0.2 % rms emittance increase If amplitude of 50 Hz line is increased by 10 linear, we get 27 % emittance increase with bunch centre reduced in population

Circulating beam at 450 GeV/c with 8 MV, 0.7 eVs (fs0=63 Hz).

50 Hz line multiples do not hit the populated synchrotron frequency band -> no significant effect observed in simulations1 ps rms white noise now gives 0.1 % loss after 1 hour.

(Further improvement with Klystron Polar Loop)

RF Noise – additional slide from previous MAC

28LHC MAC June 08 - RF Commissioning in Point 4

Class/ Case

Risk Situation Heat load Mass flow

Pressure reached (bar)

Derogation

1a) Static losses D line blocked, no wrl

150 W 17 g/s 1.8 with SVs (4x2mm dia. needed)

Tank cold - 1.8 bar max

1b-1) D line overpressure, non-return valve failure (open) 5 magnet quench

2 Kg/s 1.8 with SVs

(4x23mm. needed

Exceptional - 1.8 bar max.

1b-2) D line overpressure, non-return valve failure (open) 25 magnet quench

10 Kg/s 2.1 with RDs

(4x36mm needed)

Exceptional - 2.1 bar max.

1b-3) D Line overpressure warm, non-return 5% leakage 25 magnet quench 20 bar

10 kg/s 2.1 with RDs

(4x34 mm needed)

Exceptional – 2.1 bar max

1c-1) C line blocked open (cold) 350 g/s 1.8 with SVs (4x10mm needed)

Tank cold – 1.8 bar max

1c-2) C line blocked open (warm) - 2 x 1.5 bar SVs per module

80 g/s 1.5 with special SVs (2x24mm needed)

1.5 bar max - Safe.

1d) Insulation vacuum break 11.4 kW 1.27 Kg/s

1.8 with SVs (4x18mm needed)

Exceptional - 1.8 bar max Opening of cryostat discs (P<1.5 bar)

1e) Sustained RF quench 150 kW 2.9 Kg/s

2.1 with RDs (4x48mm needed)

Exceptional & worst case - 2.1 bar max.

1f) Beam vacuum break (50 mm aperture – 350g/s air indrawn)

147 kW 2.8 Kg/s

2.1 with RDs (4x48mm needed)

Exceptional - 2.1 bar max.

2a) Beam vacuum break (100 mm aperture)

480 kW (HL limited

by tank surface area)

9.2 Kg/s

12 bar (Pressure due to

50 mm piping)

Exceptional & exceeds press test, even with opening of RDs. Risk of rupture He tank & opening of cryostat discs (P<1.5 bar).

Risk Analysis for SC Cavity He Tanks