Radiation monitoring: what do we have and what do we need?

1. Radiation monitoring: what do we have and what do we need? M. Calviani, M. Brugger, P. Peronnard, J. Saraiva, G. Spiezia (EN/STI) R2E/Availability Workshop October 2014

2. Summary • Use of the monitoring system • Brief summary of Run I experience • RadMon development • Injectors monitoring • Requirements from users • What would be needed for Run II M. Calviani: Radiation monitoring - R2E/Availability Workshop

3. What do we use the monitoring for • Measurement of radiation levels in the machines: • High energy hadron fluence (HEH) • Total ionizing dose (TID) • Understanding of the radiation field in the tunnel and shielded areas and support for simulation extrapolation • Important service to equipment groups for failure analysis • Input/requirement for equipment design M. Calviani: Radiation monitoring - R2E/Availability Workshop

4. What would happen if don’t have it • Cannot correlate equipment failure with radiation levels  risk of changing equipment w/o solving the problem • Cannot anticipate need for equipment upgrades – rad-tolerant • Cannot study radiation impact of changing operational parameters • Cannot dissociate the possible radiation source • Limited info on eventual radiation quantity responsible for degradation (TID, NIEL, HEH) M. Calviani: Radiation monitoring - R2E/Availability Workshop

5. Types of detectors employed M. Calviani: Radiation monitoring - R2E/Availability Workshop

6. LHC RadMon coverage • LHC • Critical areas (UJ, RR, US, UX, RE, UA) • DS and start of ARC • LSS • Experiments M. Calviani: Radiation monitoring - R2E/Availability Workshop

7. RadMon locations in DS/ARC • DS/ARC (from cell 7 to 20) • RadMon are placed below the interconnect between the last MB/MQ of a given cell • Equipment below MB/MQ! cell i cell i+1 MQ MB MB MB Tunnel equipment (QPS, CRYO, BLM or EPC) cell i+1 cell i MB MB MB MB MQ • Dedicated LHC-MD  extraction of an operative ratio between BLM dose and expected HEH from RadMons = ~1 SEU count/mGy M. Calviani: Radiation monitoring - R2E/Availability Workshop

8. Experience from Run I (1/5) • Nice summary of Run I observation is available here • Radiation levels summarized with the use of different types of detectors (RadMons, BLMs, FGCs, etc.) M. Calviani: Radiation monitoring - R2E/Availability Workshop

9. Experience from Run I (2/5) • Lesson: • Important to follow-up machine operational parameters (TCL/RR) M. Calviani: Radiation monitoring - R2E/Availability Workshop

10. Experience from Run I (3/5) • Lessons: • BLM analysis fundamental for the DS/ARC • When BLM/RadMon available, good agreement between them Point 4 M. Calviani: Radiation monitoring - R2E/Availability Workshop

11. Experience from Run I (4/5) • Very important to follow-up radiation monitoring following operational variations • Sometimes just scaling is risky... Predictions 2012 Observations end 2012 Decreased: TCL closed Increased: tight collimators Increased: higher cum. lumi M. Calviani: Radiation monitoring - R2E/Availability Workshop

12. Experience from Run I (5/5) • We should not forget the p-Pb and Pb-Pb runs • Due to the Bound-Free Pair Production (BFPP), even for short runs, radiation levels can be up to 5 times those of a “standard” pp run • DS cells most affected ~3 days ~7 months M. Calviani: Radiation monitoring - R2E/Availability Workshop

13. Open points in view of Run II • 25 ns operation uncertainties: • Evolution of beam-gas levels during 25 ns operation still to be fully clarified • During Chamonix 2012 it was stated that pressure will not increase more than 2x with respect to 50 ns • However – experience showed that pressure variation depends strongly on real operational parameters Still an open point M. Calviani: Radiation monitoring - R2E/Availability Workshop

14. Open points in view of Run II • LHC Point 4 and Point 6 • UX45: radiation levels in 2012 higher than expected from 2011  triggered TE/CRG relocation activities • How the situation will evolve with 25ns operation? • UX65: still calm, as no special equipment might increase the beam-gas interaction • Monitoring has been improved M. Calviani: Radiation monitoring - R2E/Availability Workshop

15. RadMons developments • During LS1 more than 100 RadMons have been installed in machines • 450 in total • Injectors, target area, experimental areas.. • LHC: ARC P1-2-5-8 + relocations for R2E • RadMon v5 • LHC • RadMon v6 • Experimental areas (n_TOF, AD) • Injection lines M. Calviani: Radiation monitoring - R2E/Availability Workshop

16. RadMons development • Features of v6: • Remote configurability • Self-diagnostic • Radiation resistance 3 times higher • New sensors • Advantages with respect to v5: • Resolution improved by a factor of 10 • Reduced number of tunnel access to change settings • Longer life-time M. Calviani: Radiation monitoring - R2E/Availability Workshop

17. RadMons development • Overall resolution improvement – factor of 3 to 10 • TID limit 3x times larger M. Calviani: Radiation monitoring - R2E/Availability Workshop

18. BatMon – versatile instrument • Where versatile installation is required • E.g. PLC failures in LHC Point 4 and 6 requiring urgent checks • Validation of the relocation strategy • Measure R-factor in critical area via voltage change • Measurement requests for machine studies M. Calviani: Radiation monitoring - R2E/Availability Workshop

19. Injector’s radiation monitoring • R2E up to 2012 concentrated on the LHC, in order to mitigate radiation effects for Run 1 • However issues are present in the injector chain as well, simply “less visible” • In order to guarantee machine availability also in the future, it’s important to dedicate resources on it as well • Info available at http://r2e-injectors.web.cern.ch/ M. Calviani: Radiation monitoring - R2E/Availability Workshop

20. Issues with present radiation monitoring • BLMs(ACEM – Aluminum Cathode Electron Multipliers) • Saturation in critical areas, of no use for loss distribution • Not calibrated to dose • Ongoing campaign to install LHC-type BLMs in PSB (not PS)  important to be able to evaluate cumulative dose • SPS ionisation chambers – low granularity (1 every 32 meters) • HLD (not online system) • Radiation Surveys • Depends on activation, cannot directly relate to rad levels for equipment M. Calviani: Radiation monitoring - R2E/Availability Workshop

21. PSB example (RS vs. HLD) M. Calviani: Radiation monitoring - R2E/Availability Workshop

22. PS example (RS vs. HLD) M. Calviani: Radiation monitoring - R2E/Availability Workshop

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25. Injector monitoring - future • Requirements: • Appropriate BLM coverage with sufficient granularity in PS/PSB/SPS • RadMon installation extension • Passive dosimetry • Important to follow-up this measurements and improve analysis speed M. Calviani: Radiation monitoring - R2E/Availability Workshop

26. Requirements from users • A weekly report was published during 2011/2012, providing radiation levels in critical areas • Service to users in support of the RadWG M. Calviani: Radiation monitoring - R2E/Availability Workshop

27. Requirements from users • However: • It was a manual system, requiring full support from the MCWG team • Difficult for users to understand levels if equipment away from the detector location  interpretation/extrapolation from MCWG team needed • Loss scenarios can modify radiation levels distributions • Investment should be made to try to automatize it! M. Calviani: Radiation monitoring - R2E/Availability Workshop

28. Requirements from users • An attempt of realizing an online system was performed in collaboration with EN/ICE LHC R2E Dashboard • Complex to maintain, since as of now data requires manual manipulation Dedicated support of EN/ICE requested to revise the system M. Calviani: Radiation monitoring - R2E/Availability Workshop

29. What will be needed for Run II • Reactivation of the MCWG analysis team • Dedicated support from the BLM team to provide cumulated doses on a weekly basis • RadMon team to continue support the detectors • Continue keep track of the detectors inventory (Layout DB?) • Support of the groups for fast reporting on equipment failures • Continue improving on radiation monitoring in the injectors M. Calviani: Radiation monitoring - R2E/Availability Workshop

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31. Fundamental to follow-up on these, at the moment done manually! M. Calviani: Radiation monitoring - R2E/Availability Workshop

32. Conclusions • Monitoring is and will be an important aspects of the R2E (and Availability) activities • In the LHC and in the Injector chain • It is now required as a service rather than studies • Powerful instrument that allow providing a service to equipment owners in understanding radiation-related failures M. Calviani: Radiation monitoring - R2E/Availability Workshop