Transcript Radiation Monitoring in ALICE

Radiation Monitoring in ALICE
Andreas Morsch
ALICE Technical Board
27/4/2004
Outline
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Introduction
Radiation Monitoring at CERN
Technologies
ALICE requirements
Time Schedule
Introduction
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We need Radiation Monitoring for
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Mapping of radiation field, to check
accuracy of background simulations and
identify possible leaks
Long-term monitoring of integrated
radiation exposure
Online monitor for beam conditions and
possibility to request beam-abort
Post-mortem analysis of accidents
Radiation Monitoring at CERN
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Two Working Groups
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RADWG: Radiation Monitoring of the LHC
Machine
RADMON: LHC Experiment Radiation
Monitoring
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Chair: E. Tsesmelis
So far three full meetings (including one common
RADWG+RADMON meeting)
Last meeting 6/4/2004
http://lhc-expt-radmon.web.cern.ch/lhc-expt-radmon/
Radiation Monitoring at CERN
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CERN PH-TA1-SD Group
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Support and development in the field of Solid State
Detectors
Radiation Hardness Tests
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Significant amount of theoretical knowledge and practical
experience in radiation related effects and dosimetry (RD50
Collaboration)
Irradiation facility in the PS East Hall.
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Passive dosimetry
In collaboration with F. Ravotti (TS/LEA): active dosimetry,
development of online monitors for CMS
Proposal:
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Continue and extend dosimetry developments to serve all LHC
experiments.
TA1-SD Proposal
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Develop and characterize dosimeter boards with on-line
readout for and together with the LHC experiments
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Boards being as flexible as possible (dose/fluence range,
sensitivity, particle type, shape of board …) in order to
allow and optimal adoption to specific sub-detector
environments.
Output signal compatible to all Detector Control Systems
Provide the dosimeter boards and/or active dosimeters
to the experiments
Support the experiments in qualifying passive
dosimeters
What TA1-SD will not do
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Impose their radiation monitoring concepts on the
experiments
Integrate the dosimeters / dosimeter boards into
the experiments
Passive Dosimeters
LiF crystal
PAD (Alanine)
Dye films
RPL
HPD
Dose
Range
10 mGy to
100 Gy
1KGy to
100MGy
10Gy to 1MGy
1-250Gy
10KGy-1MGy
100mGy to
1MGy
10 KGy to
10MGy
Readout
technique
Heating; Light
emission
Light
absorption
EPR
Densitometer
UV (365nm);
Light emission
Pressure
measurement
Comment
standard
device
Thermal
neutron
measurement
Type of dosimeter
TLD
Very small
LiF Crystal
LiF Crystal
Dye Film
Dye Film
TLD
TLD
Alanine
Alanine
RPL
RPL
HPD
1.E-04
HPD
1.E-02
1.E+00
1.E+02
1.E+04
1.E+06
1.E+08
Dose [Gy]
Data: I.Floret (SC/RP – High level dosimetry
)
Active Radiation Monitors
RadFETs
Build-up of charge in MOSFETs SiO2 layer
(Ionizing Dose)
 (integrating measurement).
Optically Stimulated
Luminescence (OSL)
p-i-n diodes
Bulk damage in high r Si-base
(particle fluence)
 (integrating measurement).
Charge buildup in sensitive material detrapped by IR
stimulation (Ionizing Dose)
 (instantaneous measurement).
Ionization (DOSE)
Displacement in Silicon
(Particle Fluence)
Instantaneous Dose Rate
RADFET
OSL
Photo-diode
Pin-diode
Pin-diode
integrating
integrating,
erased by readout
integrating
integrating
instantaneous current
Operation
unbiased
dark
unbiased
~ 100V (reverse)
~100V (reverse)
Read-out
IDS=10-200mA
(~5s)
IR 800-1500nm
1mA (forward,
~200 ms)
~100V (reverse)
~100V (reverse)
Signal
VDS= 1-20V
Light 500-700nm
Forward bias
Leakage current
Induced current
Range
10mGy10KGy
10mGy – 100Gy
1012-1015 cm-2
1011-1014cm-2
Sensitivity
1-100 mV/Gy
Decreasing with
integrated dose
… depending on
photo sensor…
~150mV /
1012 n/cm2
~1mA /
1012 n/cm2
~1nA /
50mGy/s
has already
been used in
HEP
erasable, sensitivity
does not decrease,
can be adopted to
measure fast and
thermal neutrons,
used in satellites
COTS,
very low cost
has already been used
in HEP, high
sensitivity in low
fluence range
has already been used in
HEP;
beamdump trigger
signal needs T
correction, nonlinearity
New technology in
HEP, needs
development
Annealing not
well charact.,
signal needs T
correction
annealing difficult to
simulate, signal needs
T correction
- background current
increasing with lifetime
(irradiation)
~140 CHF
~200€
(non commercial)
~2€
~ 150 € (??)
(non commercial)
~ 150 € (??)
(non commercial)
Positive
Negative
Costs for one
mounted
device
(BCM activities)
Dosimeter Integration
RadFETs  TID [Gy] {g, HEP}
(1.6 mm)
(0.4 mm)
BPW34F
BPW34F/Pad  Fequivalent [cm-2] {HEP, nF}
OSLs  D [Gy] {g, HEP}
Pad
n-OSLth  Fth [cm-2] {nth}
Front-end
Front-end
Front-end
n-OSLF  FF [cm-2] {nF}
 We plan to put a very early prototype board into our irradiation facility this year
Other Projects
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LHCb
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Metal foil detector for RM of Si Tracker
low-mass, simple, cheap, any-size and
shape, ...
thickness < 1mm possible
TeVatron and HERA
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Large experience
Redundant measurements
Many technologies
Still evolving
ALICE Requirements
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Integrated dose / year
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0.1 mGy – 0.3 kGy
Hadron fluence 107 – 1011 cm-2 / year
Monitor beam condition with possible
request of beam abort
~20 positions inside and outside L3 at
different distance from beam pipe
Time Schedule (Experiments)
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- June 2004
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Experiments nominate contact persons
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For ALICE: Marc Tavlet, CF, AM
Until end 2004
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Experiments work together with Ch.
Joram on a document describing the
conceptual lay-out of the RM system
Discussion based on questionnaire
Questions to experiments
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Measurement for which purpose?
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Instantaneous dose rate measurement needed ?
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trigger on too high dose rate/flux needed? if so, in which time scale?
Measure which kind of information?
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(Beam dump?  Beam Condition Monitor Group)
Detector protection (e.g. switching off a sub-detector) ?
Test of radiation shielding?
Long term monitoring?
Analysis of beam accidents?
ionizing dose
displacement damage
thermal neutrons
Dose/Fluence range and sensitivity needed?
Active and/or passive devices ?
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readout cycle? / replacement cycle?
Questions to experiments
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Number of monitoring modules?
Environment of module?
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Space constrains?
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Radiation hard electronics on-board needed (OSL needed)?
Specific restrictions due to the individual experiments?
Which kind of signals can be accepted by the detector control system of the Experiment?
Deadlines
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Will we be able to repair/replace/upgrade them?
Readout:
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Maximum size of sensor module?
Distance between sensor and readout electronics (cable length)?
Lifetime of modules?
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Temperature and Temperature stability?
Decision about size of the module
Decision about number of cables
Decision about signal type
Installation deadline
Service/Maintenance after installation
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Which kind of service/maintenance is expected after installation?
Time Schedule (TA1)
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End 2004
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Mid 2005
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First prototype of integrated board and readout
system tested
Components of radiation monitoring board fixed
End of 2005
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Full prototype tested
Start of mass production