Development of

electronics for radiation

monitoring and solid state

detector R&D Isidre Mateu Suau (EP-DT-DD)

Supervisors: Michael Moll, Federico Ravotti

FTEC 2nd workshop

27/04/2016

Outline

1. Activities in the Solid State Detector (SSD) team

2. Activities in the Irradiation Facilities (IRRAD) team

3. Short term & challenges

SSD team Part of EP-DT-DD section

Study of radiation damage on silicon detectors(part of RD50 collaboration)

Different test setups are maintained within the team, for

the characterization of silicon sensors before and after irradiation. Those include:

• Probe station for C-V, I-V characterization • Several setups featuring illumination of detectors

using lasers or radioactive sources to study charge

collection efficiency and distribution, electric field shape, homogeneity…

• Cryocooler to measure the temperature dependence of the leakage current Study of defects in silicon after irradiation

My activities…

Provide service to users (Maintenance and operation of the test setups)

Research activity in the frame of RD50.

• Involved in the “Acceptor removal” project (decrease in P+ doping concentration in silicon with irradiation)

Currently working to improve the accuracy of the temperature measurement in our cryocooler

TCT setup (laser induced pulses)

CV-IV probe station

Work on the cryocooler Purpose: measurement of the leakage current in a silicon diode as a function of the temperature

From 20K to room temperature with a controlled heating rate A calibrated temperature sensor is used as a reference Measured currents when heating up and cooling down don’t overlap Error in the temperature

measurement Main problem: bad thermal conductivity of our PCB substrate

~6K Sensor colder than DUT

when warming

up

Mounting of a silicon diode on the

cryocooler sample-holder

Measured current on a diode (Heating up/cooling down)

Design of a ceramic PCB

Dummy test with a ceramic PCB has given satisfactory

results I am currently designing a PCB adapted to our needs and

compatible with the rest of our setups

Design using Allegro suite Allegro coupled with Pspice simulations in order to study

the integrity of the laser induced pulses (sub-nanosecond regime)

PCB design - Simulated transmitted

pulse for different design options

Ceramic PCB test – measured current putting a

pt1000 in the place of a diode

Ceramic PCB test – mounting on the

sample holder

Outline

1. Activities in the SSD team

2. Activities in the IRRAD team

3. Short term & challenges

EP Irradiation facilities

Irradiation team (EP-DT-DD) maintains and

operates • IRRAD proton facility: T8 proton beam-line

(24GeV/c) at the CERN PS East Hall (bldg.

157) • Gamma irradiation facility (GIF++): Caesium

irradiator, located at SPS North Area Support to the EP department and CERN users in

planning irradiation experiments

http://ep-dep-dt.web.cern.ch/irradiation-facilities

My activities… Development of a portable readout system for a

radiation monitor in the frame of the RADMON

project Interface between the SSD team and IRRAD for

the irradiation of silicon sensors IRRAD proton facility

GIF++

RADMON project F. Ravotti thesis (2006) Characterization of sensors for radiation monitoring and design of

RADMON board carrying: • PIN sensors to measure displacement damage or non ionizing energy loss (NIEL) • MOSFET sensors (RadFET) to measure total ionizing dose (TID)

RADMON readout • Same scheme for all devices.

• Current implementation: o With basic laboratory testbenches (small experiments/irradiation tests)

o LHC experiments: dedicated (but complex) readout system embedded in the DCS.

G. Gorine (Bsc thesis) worked in the development of a portable, low cost readout system. A first prototype was produced but some issues were found: • Real performance of the power supply ≠ manufacturer datasheet

• Optimum reading of PIN diodes (within 50 ms) was not possible in all conditions.

HV 3

1

2

4

Portable readout system

RADMON board

1. Full characterization of the power supply, with special attention to the

ranges of interest for the readout of each sensor • Ripple, overshoot and time to settle were systematically measured, and

“Compliant region” plots were produced by setting thresholds for each

characteristic

• Requirement on the time to settle has to be relaxed from 50ms to 100ms for

the PIN diodes.

2. Optimization of the filters for each dosimeter • Simulation to try to reproduce the behavior of the power supply

• In particular, we want to minimize the amount of current injected to the PIN

diodes during short current pulses (e.g. damage to the devices)

3. Implementation of a readout protocol in the microcontroller 4. Finalization & test of the prototype in the EP facilities

RADMON project - Work plan

101

102

103

104

10-2 10-1 100 101 102

Io[uA]

Vo [V]

Compliant region (Ripple = 10%, Overshoot = 10%, Time to settle = 100ms)

REM LAAS BPW LBSD

Io = 25 mA

Vo є [1,10] V

Tr = 50 ms

Io = 1 mA

Vo є [0.5,80] V

Tr = 50 ms

101

102

103

104

10-2 10-1 100 101 102

Io[uA]

Vo [V]

Compliant region (Ripple = 5%, Overshoot = 5%, Time to settle = 3000ms)

REM LAAS BPW LBSD

Io = 100 µA

Vo є [3,10] V

Tr = 3000 ms

Io = 160 µA

Vo є [3.5,40] V

Tr = 3000 ms

Compliant region for PIN diodes Compliant region for RadFETS

Characterization

testbench

Outline

1. Activities in the SSD team

2. Activities in the IRRAD team

3. Short term & challenges

In the SSD team…

Finalize and produce ceramic PCB

New design of the cryocooler sample-holder and connections

RD50 workshop in June

In the IRRAD team…

Continuation of work with the RADMON reader

Participate with the IRRAD team in the irradiation run 2016 (starting

today!)

Experimental determination of the hardness factor of the proton irradiation

facility

Short term & Challenges