Instrumentation and Toolsfor LIU and HL-LHC

B. Mikulecwith the invaluable input from

many colleagues from ABP, OP, RF and BI

HL-LHC/LIU Day 15th of October 2015

Introduction

• Well adapted beam instrumentation is a key element for the assessment and delivery of the requested LIU/HL-LHC beams.

• This presentation will point out discrepancies between the wish list per machine and what is foreseen within the LIU and consolidation projects. Ongoing work that seems to be under control will not be mentioned.

My apologies already at this point that it is not possible with this presentation to give adequate credit for the huge work effort within BI and other involved equipment groups and services!

Instrumentation for Linac 3

• Direct transverse emittance meter after accelerating tanks missing• Reconsider quad scans in ITH/ETL lines; requires manpower and time investment

for studies and application (fellow or technical student?)

• Study might lead to new specifications for profile monitors • Lacking precise beam current measurements to fine-tune transmission; new

request for Faraday Cup in ITF line; ABP preparing specifications • Resolution of LBS not sufficient for ions (energy spread measurement

needed after debuncher to set up long. parameters in stand-alone mode)• Study of new spectrometer line has been stopped

• Miss pickups in transfer lines; ABP to provide specifications and BI to investigate feasibility of installing pickups in ITH and ETL lines

• Increase resolution for the SEM grid in ITL and/or ITM; layout change requests being finalised by ABP

Remark: These are new requests resulting from the last analysis of the Linac 3 performance. To be evaluated.

Instrumentation for LEIR

• Transverse Schottky measurement to be made operational: need BI support (new solution for ELENA will be implemented) and software. To be installed during 2017.

• IPM: Work ongoing to transform ‘expert’ transverse profile measurements to routine operational measurements

Instrumentation for PSB

Beam instrumentation needs well covered by LIU plus consolidation.

Main concern: Will the instruments fulfill the specifications? For most of the novel injection instrumentation (H0/H- current monitor,

stripping foil current monitor, diamond BLM etc.) the Half-Sector-Test should be able to answer this question

Turn-by-turn orbit measurement system: 3 pickups with new electronics to be evaluated before the end of the year to confirm system exchange during EYETS

Flat BLMs to be evaluated for the ring; hopefully cabling (and thus installation) can be implemented during the EYETS

New Fast Wire Scanner: One prototype is planned to be installed during the EYETS

• Tune pickup (1 per ring) has to be upgraded for low-intensity beams (in particular needed during commissioning of Linac 4 beam after connection); very recent request being looked into by BE-BI and EN-MME (EYETS tight, but possible).

Instrumentation for PS

Complete set of instrumentation will be available if all instruments will be compliant with the specifications (new slow&fast BLMs, new injection devices, new injection profile monitors plus already existing devices).

• Beam Gas Ionisation (BGI) monitor based on pixel readout for horizontal plane to be installed during June TS 2016 (eventually without the magnet). New instrument!

• Signal should be sufficient for beam profile, but maybe not for the few-turn average bunch-by-bunch. Gas injection foreseen, but not compatible with ion operation (will therefore not be installed)

• Detector for vertical plane might come only after EYETS (tbc)• Comparison with wire scanner for absolute emittance values, but absolute values are

anyway not needed for emittance blow-up monitoring• Fast Wire Scanner:

• Would be important to evaluate prior to LS2, needs to be confirmed if installation during YETS 2017/18 possible (priority given to PSB due to more stringent space restrictions)

• Some remaining inconsistencies/open issues with measurements/calibration; still differences between 10/15 m/s wire movement speed or between IN and OUT scans for current wire scanners

• Bunch-by-bunch measurement will only be available with fixed 40 MHz clock, but would need different frequencies for valid characterisation before extraction

Instrumentation for SPS (1)

No solution for reliable bunch-by-bunch transverse beam measurement at flat top for 288 LIU bunches (important e.g. for electron cloud)! No full transverse qualification of LHC beams possible before LHC injection.• Wire Scanners: Evaluation of installed wire scanner prototype; review

locations (+vertical and horizontal measurement in parallel; final list of scanners being discussed); install diamond detectors in // to PMs; optical fibres to replace long cables. BUT: won’t solve problem of max. intensity at flat top

• BSRT to be made operational only for measurement at flat top (FESA class, calibration etc.); bunch-by-bunch with gating possible (not enough time for all bunches). Should change location (very high hor. dispersion), electronics redesigned and software to be written, installation of parallel system (slit + intensified PM) would be very nice…

• BGI: Would be very interesting to have it working! Multiple measurements along the cycle possible. Open issues: Understand/solve radiation issues (camera), commissioning and integration (LSS5)

Instrumentation for SPS (2)

• BLMs: • Faster BLMs at certain critical locations (turn-by-turn losses

compared to 20 ms integration time; injection losses etc.); general upgrade only during LS3; specifications and locations to be agreed upon; critical locations for partial installation before LS3 to be defined

• Diamond BLMs for extraction losses, at scrapers (deduce qualitative transverse bunch-by-bunch information) and other dedicated positions for continuous loss measurement to be made operational maybe profit from Fast BCT readout development

• BLMs requested by BE-OP for TT10; budget not assured.

Remark: Specifications for each requested system or for modifications being prepared by OP for engineering checks.

Instrumentation for LHC (1)

No solution for reliable bunch-by-bunch transverse beam measurement for the full beam and along the cycle! • Wire Scanner (WS): For HL-LHC new wire scanners with max. 20 m/s will

be installed higher resolution, but will only yield an average emittance value. Intensity threshold increased by factor 20, but would need collimation to avoid quench.

• BSRT: Calibrated with low-intensity WS measurement; large correction factors due to diffraction. Sequential scan over filled bunches takes long (~5 b/s; plan to install new cameras and R/O system to achieve almost 100 b/s), measuring on ramp below 2 TeV impossible, but currently only bunch-by-bunch measurement device for full beam, including at flat top; R&D of interferometer at FT to overcome resolution limitations

• BGV: Currently only on beam2 and half of the detector; LHC-b readout electronics to be commissioned this year; bunch-by-bunch measurement within minutes possible, also during ramp; depending on admissible gas pressure

• BGI: Only used for ions; issues with lifetime of camera

Instrumentation for LHC (2)

• Tails: With WS only for a few bunches at injection; halo monitors planned for HL-LHC (prototype of coronograph (BSRT blinding out core of bunch) maybe installed next year; gas jet monitor or other solutions to be evaluated)

• Maybe some of these options could also be applied for measurements at SPS top energy, but certainly won’t be available for LS2.

• Better pickup resolution needed for HL-LHC around collimators (alignment) and insertion regions (precise beta-star control) new electronics (DOROS; orbit and turn-by-turn). Need to combine with consolidation specifications and MD needs (e.g. for bunch-by-bunch position measurement)

• Pickup calibration reproducibility of ~1% needed for HL-LHC in the IRs (challenging beta* control); discussions started to define actions

• Bunch-by-bunch tune measurements: some improvement potential

• Data logging for bunch-by-bunch data might become an issue (e.g. head-tail, instability monitor and damper)

Tools: Automatic Beam Quality ChecksMachine Transverse Longitudinal

Linac3/4, LEIR, PSB - -

PS - Few last turns will be logged and can be analysed offline in case of need (but not enough time between bunch rotation and extraction to reject beam)

SPS Orbit at flat top drifting over days – should constant monitoring tool be put in place?

Beam Quality Monitor (BQM) satisfactory

SPS OP is working on SPS-QC, an extensive quality control program that should check during injection e.g. steering, phase, energy error, bunch length, transmission etc.; similar approach also for extraction

LHC BQM upgraded and satisfactory

Automatic quality checks with IQC at injection (trajectories, losses, phase errors, filling scheme correspondence etc.); punctual manual checks with WS (144b) + continuous BSRT scansObservation box is being prepared for transverse damper based on turn-by-turn bunch position, and could also be used for longitudinal observations (select either one bunch over many turns or a few turns for certain bunches); very useful for MDs and instability studies. Status report at LMC Oct. 14th 2015.

Transverse Beam Quality Tracking along LHC Injector Chain

• Automatic beam quality monitor for the transverse plane not existing yet.• Working group ‘Monitoring LHC beam quality from injectors’ has put

in place additional information in the LHC supertable for the injectors to at least track the evolution of transverse emittances, bunch intensity and tail population

• https://acc-stats.web.cern.ch/acc-stats/#lhc/injectors• Procedure in place in all injectors to manually initiate wire scanner

measurements before each LHC fill• Plot with brightness evolution for PSB, PS and SPS generated

automatically (see next slide); other plots of interest will follow

Brightness Evolution Plot for LHC p Injectors

Implementation of plots sorted by ‘beam types’ still to be done; will provide comparable brightness figures throughout all machine per LHC beam type.

TO BE UPDATED….

Conclusions (1)

• BI team is putting a huge effort in providing adequate beam instrumentation for LIU/HL-LHC – no time to acknowledge adequately in this presentation.

• Some requests from Linac 3 not yet included in Upgrade/Consolidation.• Other machines upstream of SPS well covered by upgrade/consolidation

projects for beam instrumentation (performance checks outstanding).• SPS+LHC: Bunch-by-bunch transverse measurements for full

operational beams (including tails) is a clear concern. • Wish to increase SPS BLM coverage. Under discussion.• Specifications for new instruments, FESA classes or requested

modifications not always available. Should be reviewed in the various LIU projects and by HL-LHC between the BI coordinators and BE-OP+BE-ABP.

Conclusions (2)

• With the ever-increasing performance of the beam instrumentation the request for and implementation of automatic quality checks will grow.

• Data logging might become an issue with the increased number of bunch-by-bunch measurements need to include online data reduction mechanisms?

• Sometimes also OP manpower missing to provide more ‘fancy’ applications that are needed once new BI systems have shown to work and/or to explore the full power of certain beam instruments.

• Support/Consolidation for already existing instrumentation has to be kept high/assured, as it’s the basis for good beam operation, also for the phase after the upgrades.