radiation monitoring technologies for the lhc
DESCRIPTION
Radiation Monitoring Technologies for the LHC. Active Radiation Monitors RadFETs; OSLs; p-i-n diodes; Passive Radiation Monitors. Federico Ravotti (TS-LEA-CMS) Maurice Glaser (PH-TA1-SD). Active Radiation Monitors. RadFETs. - PowerPoint PPT PresentationTRANSCRIPT
Radiation Monitoring Technologies for the LHC
Federico Ravotti (TS-LEA-CMS)
Maurice Glaser (PH-TA1-SD)
— Active Radiation Active Radiation MonitorsMonitors
RadFETs; OSLs; p-i-n diodes;
— Passive Radiation Passive Radiation MonitorsMonitors
F.Ravotti LHC Exp. RadMon Working Group 06/04/2004 2
Active Radiation Monitors RadFETs
p-i-n diodesBuild-up of charge in MOSFETs SiO2
layer (Ionizing Dose) (integrating measurement).
Charge buildup in sensitive material detrapped by IR stimulation (Ionizing Dose) (instantaneous measurement).
Bulk damage in high Si-base (particle fluence) (integrating measurement).
Optically StimulatedLuminescence (OSL)
F.Ravotti LHC Exp. RadMon Working Group 06/04/2004 3
RadFETs General(1) e-/h+ pair generation;
(2) e-/h+ pair recombination;
(3) e- (~psec) / h+ (~sec)
transport;
(4) hole trapping;
(5) Interface state delayed
buildup.
Build-up of charge in SiO2
increase of the p-MOS Threshold
Voltage integrated Dose
Measurement
Sthreshold ~ 1 cGy; S decreasing
over
Sub-linearResponses
responses
for different
tox
F.Ravotti LHC Exp. RadMon Working Group 06/04/2004 4
RadFETs Details
Vth= (particle type, energy, incidence angle, ..);
Vth= (packaging) in neutron field.
Care has to be taken in the choice of the proper
calibration & packaging for a neutron/HEP enriched
radiation environment!
1. MOS exposed in “zero bias” mode;
(2-wires only readout, bigger dynamic range)
2. Long-distance readout of Vth after IDS bias (seconds time-scale);
3. Operation at MTC: if T ~ constant, correction it is not needed;
4. Good reproducibility of the results producer selection.
F.Ravotti LHC Exp. RadMon Working Group 06/04/2004 5
RadFETs at CERN
-ray calibrations (“zero bias” mode) from producers & measured
at CERNBare die chips ~ 1-2 mm2
dimension !
F.Ravotti LHC Exp. RadMon Working Group 06/04/2004 6
RadFETs Instabilities
1. “Read-time” instability (“Drift-up”) during readout,
small error (< 5 %) avoided by fixing the readout
protocol.
Devices have to be selected on the basis of their
annealing behaviors Isochronal Annealing
2. Trapped charge annealing
prompt time-scale (i.e.
hours), can induce big errors
especially at LDR (> 20 %
in a few hrs).
3. Interface states generation
delayed time-scale (i.e.
years), can strongly affect
the devices long-time
behaviour.
F.Ravotti LHC Exp. RadMon Working Group 06/04/2004 7
RadFETs Isochrones
• Scaling annealing t
annealing T;
• Annealing periods at
increasing T;
• Charge annealing is oxide
(i.e. manufacture) dependent;
• Simple and quick way to
identify not suitable
behaviours;
• Informations about charge
spectrum in SiO2.
Regular
behaviours
Not suitable
behaviours
Data from CERN & CEM2 -
Montpellier
F.Ravotti LHC Exp. RadMon Working Group 06/04/2004 8
OSLs General(collaboration between CERN and CEM(collaboration between CERN and CEM22 – Montpellier University) – Montpellier University)
(1) e-/h+ pair generation and trapping;
(2) Infrared stimulation (800-1500
nm);
(3) Visible emission (500-700 nm)
Dose; After L.Dusseau
Material used at CERN: SrS doped
Sthreshold = 100 Gy;
S dependent on readout electronics.
Linear response
(< 100 Gy)
The readout completely
reset the sensitive
material !
24 GeV/c protons (IRRAD1)
F.Ravotti LHC Exp. RadMon Working Group 06/04/2004 9
OSLs Details1. Radiation independent response (X, , p, , e, ..);
2. OSL materials characterized with off-line measurements (test
bench);
3. Readout process takes 10-15 seconds;
4. Very low fading at room temperature (to be verified);
5. Pure OSL does not suffer radiation damage;6. n-OSL tested for the first time:
first campaign with 5 mm2
samples performed in 2
different neutron
environments.
OSL Test benchOSL Test bench
F.Ravotti LHC Exp. RadMon Working Group 06/04/2004 10
Neutron-Sensitive OSLs 1
1. The pure OSL material is sensitive to
the Ionizing radiation only;
2. The n-OSLs show a 20-times
increased sensitivity.
3. Boron doping affects fading
behaviour ?
OSLs with enhanced neutron-
sensitivity:
10B(n,)7Li Thermal
neutrons
1H(n,p)1H Fast neutronsOSL
pureOSL+BOSL+P
EOSL+PE+
B
F.Ravotti LHC Exp. RadMon Working Group 06/04/2004 11
Neutron-Sensitive OSLs 2
CERN OSL
Ljubljana OSL
Therm
al
Fast
1 %
99 %
89 % CERN-
PS
IRRAD2
Facility
(FLUKA)Ljubljana
Reactor
- Activation
measurements
-
87 % 13 %
3 % 97 %
11 %
F.Ravotti LHC Exp. RadMon Working Group 06/04/2004 12
OSL on-line approaches
The sensor works
in HEP
environment
(CERN PS-IRRAD1)
1. OSLs deposed on GaAsP
photodiodes
2. Optical-Fiber system
OSL material + Radhard electronics
= RADHARD INTEGRATED SENSOR
OSL
Designed for
SpaceIntl. Space Station,
CUBESAT / PROBA2
(50 mGy – 100
Gy)
3 cm x 1.5 cm
OSLs at the edge of a long
optical fiber LED/PD not
damaged by radiations.
OSL
pure
OSL+B
OSL+Paraffi
n
Support for off-line
readout
F.Ravotti LHC Exp. RadMon Working Group 06/04/2004 13
p-i-n diodes General
(1) Displacement damage in high Si-
base;
Macroscopic Effects:
(2) Resistivity increase (forward bias);
(3) Leakage current increase (reverse
bias); Forward bias operationForward bias operation::
A. Fast current pulse (~ms), VF on-line readout over long-distances (2-
wires);
B. Sensitivity =(w ):
w =1.2 mm S ~ 1 mV / 108 cm-2 ; range = 108 ÷ 1012 cm-2 (eq)
w = 0.3 mm S ~ 1.5 mV / 1010 cm-2; range = 1012 ÷ 1014 cm-2 (eq)
C. Commercial diodes BPW34F characterized in 2003.
F.Ravotti LHC Exp. RadMon Working Group 06/04/2004 14
BPW34F Osram diodes
(1)High-fluence measurements:
- Linear behaviour (eq):
1.0x1012 ÷ 4.0x1014 cm-2
- Sensitivity (eq):
1.5 mV / 1010 cm-2
(2)Strong T dependence:
Tc = -5 %·ºC-1;
(3)Thermal annealing:
< 10 % in the first 14 days.Max T over irradiations: ± 0.83
ºC
Response Curve
(CERN-PS IRRAD1 & IRRAD2
facilities)
(preliminary)
F.Ravotti LHC Exp. RadMon Working Group 06/04/2004 15
“Pad” structures
After M.Moll
Off-line measurements
after
annealing (4 min 80 ºC)
Reverse bias operationReverse bias operation::(see next presentations)(see next presentations)
1. ST, Italy “Pad structure” of
0.25 cm2 for bulk damage
studies;
2. Off-line characterization;
3. Very wide fluence range;
4. Complex Annealing behaviour;Possible “on-line”
implementation for high-
sensitivity fluence
measurements
F.Ravotti LHC Exp. RadMon Working Group 06/04/2004 16
Passive Radiation Monitors Polymer-Alanine (PAD) & Radio-
Photo Luminescent (RPL) Dosimeters:
• Formation of stable free radicals/color
center
after irradiation;
• Readout by
CERN SC/RP (“TIS”);
• Well known dosimetry systems.
[NIM-B 83 (1993) pp. 181-188]
Calibration campaign 2003 in the mixed /n field of CERN-PS IRRAD2 facility
GafchromicSensitive Films
• Formation of a stable dye polymer after
irradiation;
• Optical readout (color density);
• Different sensitivities/ranges
24 GeV/c protons (HD-810)
F.Ravotti LHC Exp. RadMon Working Group 06/04/2004 17
RadFETs:RadFETs:
Responses in HEP/n environments fully characterized. Isochronal annealing
studies are ongoing with setup in Lab. 14-R-012.
OSLs:OSLs:
Responses HEP fully characterized. Neutron-sensitive materials under
development.
Annealing studies & test on new on-line configurations are planned.
BPW34F:BPW34F:
Particle responses fully characterized. More on Annealing & readout
procedure.
Pad Structures:Pad Structures:
Particle responses well known. Looking forward for an “on-line” readout.
Passive Monitors: Passive Monitors:
Daily used in the operation of the CERN-PS Irradiation Facilities.
Summary
F.Ravotti LHC Exp. RadMon Working Group 06/04/2004 18
More on More on
……
and finally …
Acknowledgments …Acknowledgments …
1. p-i-n diodes; RadFETs HEP/n responses, packaging dependence, annealing &
instabilities:
CERN Technical Note EST/LEA/2003-03, July 2003 (EDMS No.
394670)
2. RadFETs fast-neutron response: Paper in preparation for NSS Rome, 2004
3. Special neutron-sensitive OSLs:
Paper submitted to RADECS Madrid, 2004 & CERN Preprints
collection
4. Integration Issues:
CERN-PH-EP-2004-04, February 2004 (Presented at NSREC
Atlanta, 2004)
5. Passive technologies, PS Irradiation facilities: http://www.cern.ch/irradiation
- M. Moll, C. Joram, E. Tsesmelis from CERN; - L. Dusseau, J R. Vaillé from CEM2 - Montpellier
University;
- G. Sarrabayrouse (CNRS, France), A. Holmes-Siedle (REM, England) for their support in
RadFETs studies;
- I. Mandic and M. Mikuz from the Josef Stefan Institute, Ljubljana, Slovenia.
F.Ravotti LHC Exp. RadMon Working Group 06/04/2004 19
Neutrons Cross-sections
F.Ravotti LHC Exp. RadMon Working Group 06/04/2004 20
Readout parameters
Active Dosimeter
External bias Readout InputPre-irradiation
outputAfter irradiation
output
Reference Val.
RadFETs not neededDC i = 10 A ÷ 160 A
depending on MTC1 V to 3 V
depending on tox
~ 10 V (1.6 m) ~ 4 V (0.25 m)
100 Gy
~ 41 V (0.25 m) 100k Gy
OSLs (2003
sensor)
± 5V (on-board electronics)
10-15 sec DC stimulation on LED with i = 50 mA
noise ~ 200 V with Gout=10
~ 2 V with Gout=10 100 Gy
BPW34F (w ~ 300 m)
not neededFast pulse (180 ms) with
Forward i = 1 mA0.5 V
~ 50 V (linear operation)
4.x1014 cm-2 (eq)
Pad structures
not neededLeakage current at full depletion V = 100 V ?
~ nA order ~ mA order1014÷ 1015 cm-2
(eq)
PT100 Temp Probe
not needed DC i = 1 mA 0.1 V (0 ºC) #