Radiation Monitoring Technologies for the LHC

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)


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


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.


RadFETs at CERN

-ray calibrations (“zero bias” mode) from producers & measured

at CERNBare die chips ~ 1-2 mm2

dimension !


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.


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


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)


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


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


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 %


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


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.


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)


“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


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)


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


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.


Neutrons Cross-sections


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) #

Documents

Radiation Monitoring Technologies for the LHC