PH-DT Science-Techno Tea1

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, 2008

PH-DT Science-Techno Tea2

LHC Detectors’ Technological Challenges

September 24, 2008

Interactions 109 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

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Radiation levels

September 24, 2008

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 CMSP.Bhat, A.Singh, N.Mokhov

Expected particle spectra in ATLAS Si-detector

A.Vasilescu, G.Lindstrom

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Radiation field in LHC detectors(photons, charged particles, neutrons)

September 24, 2008

Dose(Gy/year)

Charged Hadrons (cm2/year)

Neutrons(cm2/year)

Pixel system 105 1014 1013

Calorimeters 10 1012 1013

Muon system 10-2 108 1010

Table of Doses in orders of magnitudeDifferent energy range for different

particlesNumbers vary depending on radial

and Z positions wrt to IP

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Radiation Hard Components

September 24, 2008

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.

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Radiation effects (Silicon sensors)

September 24, 2008

PH-DT Science-Techno Tea

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/cm2/year)

• Scaling with the NIEL is considered reliable for most materials and particles

IMP. > This is not the whole story!

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Radiation effects (Gas detectors)

September 24, 2008

PH-DT Science-Techno Tea

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!

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Gas detectors in the LHC

September 24, 2008PH-DT Science-Techno Tea

0 0.2 0.4 0.6 0.8 1 1.2

ATLAS TRT

LHCb GEM

ATLAS MDT

"LHCb OT Straws"

LHCb MWPC

CMS CSC

ALICE TPC

C/cm

Accumulated charge per LHC year in C/cm• 1 LHC year = 107 sec• Different safety factors• Calculated for detectors operating at nominal conditions

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TRT Aging Test

September 24, 2008

OK

TRT in LHC Lab TestParticle rate Charged: 5x105

cm2/sNeutron: 3x106 cm2/sPhoton: 107 cm2/s

200 MHz X-rays(1 cm spot)

Gas Gain 2 x 104 2 x 104

Ionization Current Density (mA/cm)

0.1 1

Acceleration factor x10Collected charge per LHC year (C/cm)

12003, T.Akesson et al

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Irradiation Facilities

September 24, 2008PH-DT Science-Techno Tea

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

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Irradiation Facilities at CERN

September 24, 2008PH-DT Science-Techno Tea

Facility

Particle Majority of Users Status Shortfalls

IRRAD Protons and mixed field

Silicon (tracking) detectorsElectronics

In useUpgrade being studied

Parasitic to DIRACLimited rate and spaceExposure of personnel

GIF Photons (+particle beam)

LHC Muon detectors In useUpgrade proposed (2010)

No particle beamLimited rateOld, shutdown in 2009

CERF Mixed field(p+,p,K+)

Dosimetry, FLUKA benchmarking, beam monitors

Used 1-2 weeks/year Limited dose rates

TCC2 Mixed field LHC accelerator components and electronics

Off (used 1998-2004)

ParasiticResidual dose (safety, access)

TT40 Short & intense pulses

LHC collimator studies Used in 2004 and 2006

Space, safetyInterference 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.)

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Key Messages

September 24, 2008

PH-DT Science-Techno Tea

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.