Future Irradiation Facilities at CERN Status report of the working group on future irradiation facilities at CERN Helmut Vincke on behalf of the Working Group SPSC meeting, September 4 th

Outline  Motivation  Working group, composition and mandate  Present/past CERN irradiation facilities  Radiation fields produced with 24 and 450 GeV/c protons  Evaluation of the requirements for irradiation facilities  Preliminary conclusions  Outlook 2

Irradiation facilities are the crucial tools to study Damage to electronics (e.g.: CNGS, LHC …) Material damage (e.g.: LHC collimators) Detector performance under radiation Reliability of simulation codes (benchmark test) Dosimetry calibrations … CERN’s high-energy high-intensity beams are fundamental to carry out these studies. Hence, future irradiation facilities at CERN may influence the plans for PS and/or SPS beam line layouts and scheduling Motivation

Working group Following the 6 th LHC radiation workshop Nov 2007: … and in view of several funding requests for irradiation facilities (White Paper, EU projects) Safety Commission: * Fabio Corsanego - SC/GS * Hans-Georg Menzel - SC/RP * Marco Silari - SC/RP * Ralf Trant - SC/GS * Helmut Vincke - SC/RP TS department: * Emmanuel Tsesmelis - TS/LEA * Thijs Wijnands - TS/LEA AT department: * Jeremie Bauche AT/MCS AB department: * Ralph Wolfgang Assmann - AB/ABP * Markus Brugger AB/ATB * Ilias Efthymiopoulos - AB/ATB * Roberto Losito - AB/ATB * Yves Thurel - AB/PO PH department: * Mar Capeans - PH/DT * Lucie Linssen - PH/DI (chair) * Michael Moll - PH/DT * Christoph Rembser - PH/ADE CERN-wide working group: 4

Mandate Essential elements of the mandate:  Collect requirements for future irradiation facilities at CERN (taking into account availability of facilities outside CERN).  Put these requirements in the context of presently available facilities/infrastructures at CERN.  Produce a report on the findings 5

Present/past CERN irradiation facilities See: 6

Present/past irradiation facilities (I)  Protons and mixed field irradiation  Up to protons/(cm 2 hr) on a 2*2 cm 2 surface  Up to neutrons/(cm 2 hr) on a 30*30 cm 2 surface (1 MeV equiv.)  Since 1992, up to 1500 irradiated samples per year  Mainly used by detector communities (trackers, electronics)  Drawback: parasitic operation (DIRAC), access via primary beam area, personnel exposure, limited space, limited rate PS East hall facility (in use) 7

Hadron beam Concrete shielding Detectors Copper target 1 m SPS, H6 beam line, 120 GeV/c Long copper target, various shielding geometries, well- defined mixed radiation fields Since 1992, 1-2 weeks per year Test/calibration of passive and active detectors (dosimetry), FLUKA benchmarking, beam loss monitor studies, … Drawback: limited dose rates, high muon background from TCC2 Present/past irradiation facilities (II) CERF facility (in use)

Present/past irradiation facilities (III)  137 Cs source irradiation over large surfaces, 740 GBq (in 1997), running the entire year  Combined with SPS West area beam (until 2004)  Clients: detector community, mainly muon detectors  Detector irradiation, and detector performance under harsh background conditions (photon source= background; particle beam= signal)  Shortfalls: need more intensity, need high-energy muon beam GIF facility (in use) 9

Test area Mixed field irradiation, high doses within reasonable time Clients: LHC accelerator groups, testing components and electronics Up to 25 experiments/year Sufficient space to test complete systems Shortfalls: o Parasitic, no reproducible radiation conditions o High residual dose rate in the area (access, safety) TCC2 target area (not used anymore) Present/past irradiation facilities (IV) 10

Present/past irradiation facilities (V) Used for LHC collimator studies and material tests in 2004 and 2006 Short and intense pulses at 450 GeV/c Up to 3.3  ppp (approx. 2 MJoule) Drawbacks: o Space too limited o Interference with CNGS operation and LHC fill o Area not ideal in terms RP aspects (production of radioactivity close to beam line elements) TT40 area (not used anymore) 11

New facility (2008) at the CNGS area (in use)  Exposure to mixed high-energy radiation fields, well-known field thanks to extensive FLUKA simulations  With full (1.2 km long) installation of services, allowing for complete systems tests (crates), SEU testing  Dose rates : o CNGS : 1 to 150 Gy per week o ARC-DS : 1 to 200 Gy per year  Drawbacks: Parasitic to CNGS, access conditions, long access tunnel, safety Present/past irradiation facilities (VI) 12

First thoughts concerning a future mixed field irradiation facility 13 For high-energy experiments in mixed radiation fields either the PS (24 GeV/c) or the SPS (450 GeV/c) beam could be used. In order to understand the advantages and the disadvantages of the two, the secondary radiation fields emerging from a beam-on-target situation has to be simulated carefully.

Simulation of radiation fields produced with 24 GeV/c and 450 GeV/c protons 14

Simulation (I) Simulation of irradiation fields using hypothetical “CERF++ facility “geometry and 24 GeV/c and 450 GeV/c proton beams Copper target 7 cm diam, 50 cm length 15

Simulation (II) 15 µSv/h Contours: 15 µSv/h 450 GeV/c 24 GeV/c Dose rate mapping at beam height µSv/h protons/spill protons/spill Outside downstream Outside lateral Inside downstream Inside lateral Reference locations 16

Simulation (III) With a factor 10 incoming particle rate difference, particle spectra at 24 and 450 GeV/c in the lateral and back-scattered positions look very similar Main difference: forward muon spectrum “Outside downstream” 17

Safety issues related to outgoing muon fluences First estimates (collimated beam assumed). Required Concrete shielding length= 2.6*Iron shielding length To be compliant with proton facility requirements we need 1.1E12 protons per spill (16.8s)  2.4E14 protons per hour To stay at a level of 2.5 uSv/h (non designated area, non-permanent access) we need: ~ 100 m of additional iron for 450 GeV/c ~ 5 m of additional iron for 24 GeV/c Simulation (IV)

Fluence comparison: LHC vs. Irradiation facility 19

Fluence comparison: LHC vs. Irradiation facility (I) Radiation field seen at the irradiation facility at position “inside lateral” (E. Feldbaumer et al. ) Fluences in the LHC tunnel (C. Fynbo, G. Stevenson, CERN, 2001) 20 LHC accelerator Very similar shape of the two spectra

Fluence comparison: LHC vs. Irradiation facility (II) 24 GeV/c 450 GeV/c Radiation field seen at the irradiation facility at position “outside lateral” (E. Feldbaumer et al. ) Particle fluence spectra for the LHCb counting barracks (C.Theis, et al.) 21 LHC accessible area Very similar shape of the spectra

Fluence comparison: LHC vs. Irradiation facility (III) Charged hadrons seen at the irradiation facility at position “inside downstream” (E. Feldbaumer et al. ) Radiation close to the innermost CMS detector layers surrounding the interaction point. (N. Mokhov) 22 LHC experiment, inner tracker Very similar shape of the two spectra

Requirements Questionnaire Requirements questionnaire 23

Requirements Questionnaire  Web-based enquiry launched to a very wide community  Enquiry addresses 5 main irradiation categories:  Pure gamma  GIF++ (gamma irradiation combined with particle test beam)  Proton  Mixed field (neutron-dominated)  High-energy high-Z ion  Questions asked on: particle energy, fluence, total dose, spill-type, irradiation surface, object dimensions, required annual access, year of operation, required peripheral infrastructure… 24

Feedback  In total 134 forms filled: 25

Feedback Proton feedback 26

Proton Facility -- Who answered ?  In total 51 forms filled:  Feedback for proton facility dominated by Inner Tracker communities of the experiments 27  Type of equipment  44% Detector and detector components  26% Material tests  12% Accelerator components  9% Radiation monitors and dosimeters

Proton Facility: Beam parameter requirements 28  Beam parameters required  Machine Community prefers 450 GeV/c and Experiment Community prefers 24 GeV/c.  The majority of the users prefer the slow (fixed target type) extraction  Collimator studies definitely require 450 GeV/c, fast extraction (CNGS type)  HiRaDMaT slides  Required maximum integrated proton fluence:  2 x10 16 p/cm 2 (94% require this or less); to be achieved in ~1 week  1.1E12 protons per 16.8s

Proton Facility: other requirements Annual beam time requirements: Collective annual requirements are compatible with one single facility. 29  Size of sample:  67% <10cm, <10kg  16% <1m, <25kg  16% >1m, >25kg  Beam size required  88% < 10cm x 10cm  8% < 25cm x 25cm  4% < 1 m x 1 m

Feedback Mixed field feedback 30

Mixed field irradiation -- Who answered ?  In total 36 forms filled CERN: mainly LHC related topics CERF: beside LHC topics also dosimetry topics for accelerators, aircraft and space applications 31

Primary beam parameters required  Preferred momentum of primary beam:  Both, 24 and 450 GeV/c is satisfying the users  Fast or slow beam extraction:  The majority of the users prefer the slow extraction 32

Radiation field conditions required (I)  Field type required (  percentage >100% due to multiple choice) :  Neutron field perpendicular to target: 83%  Field at different angles behind shielding: 42%  High dose radiation fields: 33%  Muon field: 14% note: these clients are asking for other particles as well  no “explicit/exclusive” request for muons  Others: 14% Comments: 1. Muon field is only provided by 450 GeV/c facility 2. LHC like environment was desired very often as source field 33  Annual beam time requirements:  Collective annual requirements are compatible with one single facility.

Radiation field conditions required (II)  Maximum integrated neutron fluence/ fluence rate:  2*10 16 n/cm 2  n/(cm 2 s)  Maximum dose and dose rate:  10 7 Gy  10 Gy/s 34 Size of irradiation field: Smaller than 25 x 25 cm 2 72% Smaller than 1 x 1 m 2 25% Strong correlation between available dose/fluence rate and desired irradiation surface: Close to target: high fluence/dose rate but small area with constant beam conditions

First dose/n-fluence estimates, 24 GeV/c mixed field Beam intensity of 1E11 GeV/c per 16.8 s and an continuous operation of 1 week (3.6E15 protons) Beam intensity of 1.1E12 GeV/c per 16.8 s and an continuous operation of 1 week (4E16 protons) * * An intensity of 1.1E12 protons/16.8 s requires a reinforcement of the conceptual CERF++ shielding design by 1 m of concrete in order to remain compliant with given RP constraints 35 A significant number of the dose/fluence requirements cannot be achieved in a reasonable time

Summary of inconsistency between user requirements and CERF++ irradiation parameters The final comparison is based on a beam intensity of 1.1E12 24GeV/c per 16.8 s and a continuous irradiation of 1 week. Institute / Department of the requestor Area required for irradiation in cm x cm Ratio between user requirements and CERF++ Experiment total dose / fluence dose rate / fluence lowerupperlowerupper SCIPP UC Santa Cruz10 x 10ok20 ok ATLAS PH CMT10 x 10ok 10 ok CMS PH ULB25 x 25ok50 ok ATLAS, LHCb, RD50 PH DT210 x 10ok10 ok306 PH ESE10 x 10 ok10 ok SLHC PH ESE100 x 100 ok ok LHC AB PO100 x 100ok LHC (LHC60A-08V) AB PO25 x 25 ok 1.53 LHC (FGC + 6U small electronics card) PH UAT> 100 x 100 requirements fulfilled for 1m x 1m (factor= 0.5) ATLAS 36

Feedback Heavy ion feedback 37

Heavy ion feedback  12 replies received  4 from CERN, 8 from outside institutes  The use of ions for irradiation studies is justified, as their radiation effects on materials are quite different from those induced by e.g. protons. “Conclusion”: If the availability of ions can be added at low cost to the plans for one of the future CERN irradiation facilities, they should definitely be included. 38

Feedback Photon feedback 39

The questionnaire offers two options: Pure photons: Strong gamma source for irradiation GIF++: Strong gamma source for irradiation over very large areas plus a simultaneous particle beam ANSWERS TO THE QUESTIONNAIRE Number of answers for Gamma irradiation: 35 Pure photons: 28 GIF++: 7, representing many users (LHC experiments) Photon feedback

User communities and applications Applications:  Pure photons –Radiation hardness tests of materials, small prototype detectors and electronic components. –Radiation monitors and dosimeters performance tests  GIF++ Focuses on the characterization and understanding the long-term behavior of large particle detectors. Test of detector reliability (measure particle signal) under harsh background (photon) radiation conditions. 41 User Communities: LHC experiments; mostly muon detectors AB and AT department SC (Radioprotection, Safety & Environment)

Towards Implementation of a GIF++ facility  User requirements are summarized in a dedicated document: “The GIF++ Gamma Irradiation Facility at CERN”  The document has been discussed and agreed with the users on 19/8/08  Some specifications of the new facility: Photon source: 137 Cs, 10 times stronger than former GIF source Particle beam: Muon beam at ~100 GeV/c, about 10 4 particles per spill, beam size: 10 x10 cm 2. Area size: ~ 10m x 7.5m x 3 m. The facility should be operational from 2010 for min. 5 years 42

Feedback and status Fast extraction, thermal shock tests 43

Towards implementation HiRadMat Facility In order to guarantee a safe operation of the LHC, critical beam line equipment has to be able to withstand a high-intensity, high-energy pulsed beam impact (e.g.: LHC collimators). Hence, a dedicated test facility is needed. 44   HiRadMat: high power, short duration beam impacts at 450GeV or 177GeV/n  Uses the existing SPS  LHC injection beam to create high power, short duration beam impacts at 450GeV or 177GeV/n!  Status of the implementation work  HiRadMat is included in the phase 2 collimation project (White Paper, 2008)  Dedicated working group was founded to implement the facility in the TT60 area.  AB and SC/RP are involved.  Collaboration with various outside institutes are already established

Preliminary conclusions and outlook 45

WG conclusions In view of the various demands, requirements and constraints, the working group sees the following optimized scheme for future facilities (in arbitrary order): 1. Facility for “pulsed proton” irradiations at the SPS (beg. 2010)  HiRatMat (work is already ongoing) 2. A GIF++ facility at the SPS (2010)  Specification document ready 3.A combination of proton and mixed-field facility (which can be placed behind each other in the same beam line). 46

WG conclusions 3 (cont.) About the combined proton and mixed-field facility: 2 possible options : A.PS East hall (24 GeV/c) + cost-effective solution +- number of protons marginally sufficient (to be checked further) -  requires the finishing and dismounting of DIRAC experiment!!! - PS reliability? PS lifetime? B.SPS North Area (400 or 450 GeV/c) + Required number of protons can be reached in well-shielded location - More expensive, need to fulfill shielding requirements 4.If the availability of ions can be added at low cost to the plans for one of the future CERN irradiation facilities, they should definitely be included. 47

Next steps of the WG  Work on implementation plans  Propose designs with their cost estimates  Full radiation protection studies and safety plans for proposed facilities  Write full report  Work on financing models and seek approval  The working group foresees to make another presentation in about 4-6 months from now, with a description of implementation options for the required irradiation facilities 48

END

Primary proton intensity estimates 50

Primary proton intensities Availability of primary protons from PS and SPS depends on many other clients. Rough estimate: Scenario 1: Proton flux at an PS East Area beam line, using East- C cycle Scenario 2: Proton flux at a EHN1 North Area beam line, using slow extraction Basis assumptions:  150 days of beam time per year at 100% efficiency  40-period super-cycle, including 3 CNGS cycles, and LHC pilot cycle, a fixed target cycle with long flat-top (9.6 s extraction) and an MD cycle 51

Primary proton intensities Scenario 1 PS:  3 East-C cycles, 2.5*10 11 ppp =>~2*10 17 protons per year (factor 2 can be gained if extracted at 20 GeV) Scenario 2 SPS EHN1:  2.4*10 13 protons per extraction, to be shared among north area targets and beam lines. Assume 10% available for irradiation =>~6.5*10 17 protons per year 52