Introduction to Irradiation Facilities 1. Challenges at LHC and Why we need Irradiation Facilities (Mar CAPEANS) 2. PH Department Proton and Neutron Facilities (IRRAD, B.157) (M.GLASER) 3. PH Department Gamma Irradiation Facility (GIF, B.190) (R. FORTIN) September 24, 20081PH-DT Science-Techno Tea

LHC Detectors’ Technological Challenges September 24, 2008PH-DT Science-Techno Tea2  Interactions  10 9 interactions  Selection of ~100 events/s  Multiplicity  Every 25 ns about 1000 tracks cross and leave a print on the LHC detectors  Unprecedented Radiation levels  Interactions  10 9 interactions  Selection of ~100 events/s  Multiplicity  Every 25 ns about 1000 tracks cross and leave a print on the LHC detectors  Unprecedented Radiation levels

Radiation levels September 24, 2008PH-DT Science-Techno Tea3  Estimates:  Simulation of number and momentum spectra of particles arriving to detectors at LHC reference luminosities (and machine-induced backgrounds).  Get radiation dose maps, particle fluxes and energy spectra (photons, neutrons, charged particles).  With magnets on:  They affect the low momentum particles which may loop and hit some of the detectors many times.  With detector materials (location and quantity) as close as possible to reality.  Note that radiation simulation may be wrong by some factors and long-term effects may not be fully predictable. Simulated radiation dose (Gy/s) map in CMS P.Bhat, A.Singh, N.Mokhov Expected particle spectra in ATLAS Si-detector A.Vasilescu, G.Lindstrom

Radiation field in LHC detectors (photons, charged particles, neutrons) September 24, 2008PH-DT Science-Techno Tea4 Dose (Gy/year) Charged Hadrons (cm 2 /year) Neutrons (cm 2 /year) Pixel system Calorimeters Muon system Table of Doses in orders of magnitude Different energy range for different particles Numbers vary depending on radial and Z positions wrt to IP

Radiation Hard Components September 24, 2008PH-DT Science-Techno Tea5  We need to test the resistance to radiation of every detector and of every detector component:  Detector/sensor performance  Materials  On-detector electronics  Powering and data links  Fluids (gas, cooling)  Radiation damage mechanisms and their effect differ for sensors, electronics, materials, optical fibres, etc. Inside a detector volume, we need to perform irradiation tests with different particles and energies.

Radiation effects (Silicon sensors) September 24, 2008PH-DT Science-Techno Tea6  Add Safety factors (x2, x5…)  Radiation Hardness Tests  Expose detectors and components to very large particle rates to attain large doses in a very accelerated manner  Typical test lasts between days and weeks (time needed to achieve target dose)  Detector is powered and monitored; performance is tested before/after irradiation  Add Safety factors (x2, x5…)  Radiation Hardness Tests  Expose detectors and components to very large particle rates to attain large doses in a very accelerated manner  Typical test lasts between days and weeks (time needed to achieve target dose)  Detector is powered and monitored; performance is tested before/after irradiation Detector technology dependences: For silicon, bulk radiation damage results from non-ionizing energy loss (NIEL) displacements, so total neutral and charged particle fluence is normalized to flux of particles of fixed type and energy needed to produce the same amount of displacement damage, conventionally 1 MeV neutrons (1 MeV n/cm 2 /year) Scaling with the NIEL is considered reliable for most materials and particles IMP. > This is not the whole story!

Radiation effects (Gas detectors) September 24, 2008PH-DT Science-Techno Tea7  Add Safety factors (x2, x5…)  Radiation Hardness Tests  Expose detectors and components to very large particle rates to attain large doses in a accelerated manner  Good tests are done as slow as possible (months) and irradiating areas as large as possible  Detector performance is monitored during irradiation  Add Safety factors (x2, x5…)  Radiation Hardness Tests  Expose detectors and components to very large particle rates to attain large doses in a accelerated manner  Good tests are done as slow as possible (months) and irradiating areas as large as possible  Detector performance is monitored during irradiation Detector technology dependences: For gas detectors, we consider amount of charge deposited on electrodes due to avalanches (C/cm per unit time) as the relevant magnitude IMP. > This is not the whole story!

Gas detectors in the LHC September 24, 2008PH-DT Science-Techno Tea8 C/cm Accumulated charge per LHC year in C/cm 1 LHC year = 10 7 sec Different safety factors Calculated for detectors operating at nominal conditions

TRT Aging Test September 24, 2008PH-DT Science-Techno Tea9 OK TRT in LHCLab Test Particle rateCharged: 5x10 5 cm 2 /s Neutron: 3x10 6 cm 2 /s Photon: 10 7 cm 2 /s 200 MHz X-rays (1 cm spot) Gas Gain2 x 10 4 Ionization Current Density (  A/cm) 0.11 Acceleration factorx10 Collected charge per LHC year (C/cm)1 2003, T.Akesson et al

Irradiation Facilities September 24, 2008PH-DT Science-Techno Tea10  A Facility should provide:  Broad range of (energies and) intensities of the beam  Monitoring of flux and dose  Fast and uncomplicated experimental setup  Transparent operating procedure  User friendly data acquisition system Facility with reproducible conditions, available to a large number of users and with user support/services Specialized infrastructure for a small number of expert users VS

Irradiation Facilities at CERN September 24, 2008PH-DT Science-Techno Tea11 FacilityParticleMajority of UsersStatusShortfalls IRRADProtons and mixed field Silicon (tracking) detectors Electronics In use Upgrade being studied Parasitic to DIRAC Limited rate and space Exposure of personnel GIFPhotons (+particle beam) LHC Muon detectorsIn use Upgrade proposed (2010) No particle beam Limited rate Old, shutdown in 2009 CERFMixed field (  +,p,K + ) Dosimetry, FLUKA benchmarking, beam monitors Used 1-2 weeks/yearLimited dose rates TCC2Mixed fieldLHC accelerator components and electronics Off (used )Parasitic Residual dose (safety, access) TT40Short & intense pulses LHC collimator studiesUsed in 2004 and 2006Space, safety Interference LHC & CNGS Maurice Richard Next, urgent steps: adapt facilities to current R&D needs Check discrepancies between LHC predictions and reality Particle rates at SLHC ~ 10 x LHC (new technologies, longer tests, more users, etc.)

Key Messages September 24, 2008PH-DT Science-Techno Tea12  Testing the effect of radiation on detector systems is fundamental for their correct design and operation, and specially for evaluating their lifetime in the experiments. This is a field of activities on its own!  Radiation dose maps are simulated. We need to add to same safety factors.  Damage in sensors (Si surface/bulk, gas detectors, etc), on- and off- detector electronics, etc. is due to different processes and depend on energy type and energy. Therefore, we need a spectra of particles and energies available.  Irradiation facilities should be user-friendly. Specially they must have a well characterized particle spectra to permit comparative studies.