Transcript Radiation Sensor Characterization for the LHC Experiments Federico Ravotti, Maurice Glaser, Michael Moll CERN PH/DT2 and TS/LEA.

Radiation Sensor
Characterization for the
LHC Experiments
Federico Ravotti, Maurice Glaser, Michael Moll
CERN PH/DT2 and TS/LEA
Outline

Sensor Catalogue;

Quality Assurance (QA) procedure for sensors;

RadFETs packaging;

Sensors readout board for LHC Experiments;

Sensors R&D:
 Readout procedure optimization for BPW34 p-i-n diodes;
 New p-i-n diodes from Czech Republic (LBSD);
 On-line dosimeter based on fibred OSL.
 Conclusion.
F.Ravotti
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Sensor Catalogue
(www.cern.ch/lhc-expt-radmon/)
Specifies sensors suitable for dosimetry in
the LHC experiments environment:
 Mixed-LET radiation field;
 ~ 5 orders of magnitude in intensity.
 Many devices tested but only a few
selected (e.g. only 2 out of 9 RadFETs)
2 x RadFETs (TID);
[REM, UK and LASS, France]
2 x p-i-n diodes (1-MeV Feq);
[CMRP, AU and OSRAM BPW34]
1 x Silicon detectors (1-MeV Feq).
Detailed discussion on the sensors
selection criteria  see talk at
4th LHC Radiation Day!
[CERN RD-50 Mask]
F.Ravotti
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Sensors QA Procedure
Suitable radiation response and intrinsic stability are not enough to
guarantee reliable measurements over a long time (e.g. 10 y. LHC).
RadFET LAAS 1600 nm
Tmeas = 23.0 +/- 2.0 ºC , DTmax,step = 4.8 ºC
180
Example of different
radiation response curves
for Thin Oxide RadFETs
from REM (see Catalogue).
Unannealed Fraction (%)
160
140
120
100
80
Example of Annealing
Behaviour at different
doses for Thick Oxide
RadFETs from LAAS
(see Catalogue).
60
40
20
0
0
20 40 60 80 100 120 140 160 180 200 220 240 260 280 300
Temperature (ºC)
 Compliance with electrical specifications to
keep working correctly under irradiation;
 Homogeneous initial values to insure
one by one using their preirradiation characteristics!
reproducible measurements;
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Sensors must be identified
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Sensors QA Procedure
Electrical Tests on the
Acceptance Tests
purchased sensor batches to
complies with specifications
Issue for TID Measurement
(RadFETs Packaging)
Mounting bare-die sensors in
a proper packaging
Functional Verification Test
Integration in a specific PCB
circuit “sensor carrier”
Functional Verification Test
Delivery to the LHC Experiments
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Electrical Tests
RadFETs:
•
Ids – Vds in function of Vgs;
•
Read-time stability of Vth;
p-i-n diodes:
•
I-V in forward bias;
•
Stability of VF  (t);
0.5
Example of I/V
characteristics of
not-irradiated
BPW34 diodes.
0.4
0.3
0.2
0.1
0
0.00
0.50
1.00
2.00
Voltage (V)
Detector ST W339-N11
1.0E-06
1.0E-10
9.5E-11
Silicon Detectors:
1.0E-07
•
I-V & C-V in reverse bias;
•
Stability of bulk IL  (t).
Central Current
9.0E-11
Capacitance
8.5E-11
8.0E-11
1.0E-08
7.5E-11
1.0E-09
7.0E-11
6.5E-11
1.0E-10
6.0E-11
0
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1.50
5
10
15
20
Reverse Bias (-V)
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Capacitance (F)

Ids – Vgs in linear and saturation regime;
Current (A)
•

IV Forward bias at 20.5 ºC
0.6
Current (-A)

Example of
I/V and C/V
characteristics
of notirradiated
Detectors.
30
6
1.E-03
1.E-04
1.E-05
1.E-06
1.E-07
1.E-08
1.E-09
1.E-10
1.E-11
1.E-12
1.E-13
1.E-14
8.0E-04
REM Id vs. Vgs
Vg =0 to -6V step 0.05V
Vd= -100mV, -6V
4.0E-04
VT
2.0E-04
0.0E+00
0
1
2
Vgs [V]
3
4
5
2.0E-03
0
2
Vgs [V]
4
6
Sensors Acceptance/Rejection based on:
REM Id vs. Vds
Vgs= -1, -2, -3, -4,
Vd= 1 to -6V step 0.05V
1.5E-03
Ids [A]
REM Id vs. Vgs
Vg =0 to -6V step 0.05V
Vd= -100mV, -6V
6.0E-04
Idss
Ids [A]
Ids [A]
RadFETs Characteristics
• Vth,0
• Idss
1.0E-03
• Ids-Vds immune to kink effects
• Stability of Vth (t).
5.0E-04
0.0E+00
0
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2
3
Vds [V]
4
5
6
 Tech. Spec. document existent
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RadFETs Packaging
Commercial Packaging
(i.e. TO-5, DIL) cannot
satisfy all Experiment
Requirements
(dimensions/materials)
Development / study
in-house at CERN
1.8 mm
• High Integration level:
up to 10 devices covering from mGy to kGy dose range;
~10 mm2 36-pin Al2O3 carrier
• Customizable internal layout;
• Standard external connectivity;
Packaging under validation
(including lids effect) with
GEANT4 model in
collaboration with Genova
INFN (Riccardo Capra)
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Full-Package Geometry
designed in GEANT4
Calculated Radiation Transport
Characteristics (0.4 mm Al2O3):
 X = 3-4 % X0;
 e cut-off  550 KeV;
 p cut-off  10 MeV;
 photons transmission  20 KeV;
 n attenuation  2-3 %;
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Integration Issues
ATLAS ID
(RMSB Hybrid)
BPW34 diodes
CMS (BCM 1)
4 x RADFETs
PCB with T
control
DMILL
structure
(nth damage)
PAD diode
PT1000
p-i-n diode
[I. Mandic, JSI]
ELMB (ADC) + DAQ
[A. Macpherson, CERN]
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Rest of
ATLAS
5th LHC Radiation Day 29-11-2005
General-purpose plug-on I/O module for
the monitoring and control of subdetector front-end equipment
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Sensors Readout Board
 PCB designed to host:
 1 x RadFETs Packaging (5 channels)
 5 x p-i-n sensors;
 1 x Temperature sensor;
 Fully customizable;
 Small size (15 mm x 25 mm x 5 mm);
 Signals available on a standard connector plug (12 pins) or
direct wire connection.
 Board readable with commercial electronics:
 Keithley Source-Meter 2400 and Agilent Switch Matrix;
 Price ~ 130 CHF/channel (if > 60 channels)
 PCB can be used as passive dosimeter.
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Outline

Sensor Catalogue;

Quality Assurance (QA) procedure for sensors;

RadFETs packaging;

Sensors readout board for LHC Experiments;

Sensors R&D:
 Readout procedure optimization for BPW34 p-i-n diodes;
 New p-i-n diodes from Czech Republic (LBSD);
 On-line dosimeter based on fibred OSL.
 Conclusion.
F.Ravotti
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BPW34 Readout Optimization
1) Devices not manufactured to be dosimeters
(e.g. not sensitive to low F);
iF = 1 mA  200 ms
2) Pre-irradiation helps to shift operation point
(see our last years talk);
To be studied in more detail:
A. Influence of readout parameters (current density and pulse
length) on diode’s response;
B. Long-term annealing of VF as function of IF and Temperature.
IV Forward bias after PROTON irradiation
0.5
Current (A)
0.4
Current density:
Feq
0.3
Feq > 21013 cm-2  “thyristor - like” behaviour;
(1x1011 to 1x1015 cm-2)
0.2
 Keep IF < 50 mA is a good precaution!
0.1
 Tested readout currents 1 mA, 10 mA, 25 mA
0
0
10
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Voltage (V)
40
50
60
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BPW34 Readout Optimization
Forward Voltage (V)
100
Proton
Neutron
Current density
10
(radiation response at 25 mA vs. 1 mA):
 Feq < 21012 cm-2 negligible sensitivity increase;
1
 Feq > 21012 cm-2; S (25 mA) > 36 % S (1 mA);
iF = 25 mA  100 ms
0.1
1.00E+10
1.00E+11
1.00E+12
1.00E+13
1.00E+14
 Signs of heating effects Feq ~ 11014 cm-2;
1.00E+15
-2
Equivalent Fluence (cm )
Increase of VF (mV)
Pulse Length:
 Keep the readout-time  200 ms is advisable;
10
9
8
7
6
5
4
3
2
1
0
 “optimized” pulse-length of 50 ms.
after ~ 11013 cm-2
IF = 1 mA; VF = 6.7 V
Conclusion:
Current density and pulse length have to
be adopted to the user requirements
(fluence range, current density limitations
1
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10
100
1000
Time after current injection (ms)
10000
in electronics, etc….)
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BPW34 Readout Optimization
VF/V0
-2
Annealing BPW after 1e14 cm @ 80ºC
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
1 mA
10 mA
25 mA
0
5000
10000
Time (min)
15000
20000
Annealing of VF (IF):
 Relative change of the voltage less significant at high injection levels!
(detailed study ongoing in the Temperature range 20 – 100 ºC)
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Czech p-i-n diodes (LBSD)
Long Base Silicon Diodes from CMI, Prague
1)
Cheaper compared to the High Sensitivity diodes currently
presented in the Catalogue;
2)
Two types are produced: one MORE SENSITIVE than the
currently used devices;
3)
Recommended IF pulse for readout: 25 mA x 40 ms.
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Type “Si-1”:
1.2x1012 cm-2)
• nF sensitivity: ~ 3 mV/109 cm-2
Type “Si-2”:
• KERMA: 0.01-5 Gy (Feq ~ 2x1011 cm-2)
• nF sensitivity: ~ 3 mV/108 cm-2
Annealing studies ongoing to include
these products into Sensor Catalogue!
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DF (V) at 25 mA x 40 ms
• KERMA: 0.1-30 Gy (Feq ~
Si-1 Broad n spectrum
Si-2 Broad n spectrum
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Si-1 250 MeV p Low Flux
Si-2 250 MeV p Low Flux
Si-1 250 MeV p High Flux
8
Si-2 250 MeV p High Flux
Si-1 250 MeV p High Flux
6
4
2
0
0.0E+00
2.0E+11
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4.0E+11 6.0E+11
Dose (Gy)
8.0E+11
1.0E+12
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Fibred OSLs System
Laser System Driver
Quartz Radhard Fibers
Laser Light 60 mW
Visible light
Oscilloscope
~ 5 mg
OSL
Crystal
1 mA/nW (@ OSL l)
5 V/div
1 MW DC
50 ms/div
Tested at the TRIGA Reactor of the JSI, Ljubljana (Slovenia)
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Fibred OSLs System
1)
OSL Dose Vs Integration Time
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of such a system in harsh and intense environment;
2)
7
Test condition ~200 mGy/s with feq ~1.9x109 cm-2s-1
(values referred to 250 W reactor power at Z = 0).
6
Dose [mGy]
Preliminary Results (last week!!!) show the feasibility
5
Vertical Scan of the irradiation tube
10000
4
3
Dose integrated in
6 sec time.
1000
1
0
0
5
Time [s]
10
15
Dose [mGy]
2
100
10

Sensitivity of the tested prototype ~ 0.1 mGy, but
minimal sensitivity probably higher;

probe edge dimension < 1 mm2
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1
0
50
100
150
Position [cm]
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Conclusion

Over 1200 sensors have been procured and ~ 1/3 have been tested
following the QA procedure here described. About 100 samples have been
delivered to LHC Experiments;

A dedicate packaging and a readout board for the sensors have been
produced;

R&D on sensors is carried out in parallel:

Improvement in the BPW34 readout protocol;

More sensitive p-i-n diodes are under studies  added soon to the
Sensor Catalogue;

F.Ravotti
Very promising results obtained in OSL on-line dosimetry!
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