radiation damage and annealing in 1310nm ingaasp/inp lasers for the cms tracker

August 2000

Radiation damage and annealing in Radiation damage and annealing in

1310nm InGaAsP/InP lasers1310nm InGaAsP/InP lasers for the CMS Tracker for the CMS Tracker

K. GillK. Gill, G. Cervelli, R. Grabit, F. Jensen, and F. Vasey., G. Cervelli, R. Grabit, F. Jensen, and F. Vasey.

CERN, GenevaCERN, Geneva

SPIE 4134-22 - Karl Gill et al, August 2000

BackgroundBackground

CMS Tracker readout and control projectCMS Tracker readout and control project

Complex system with >50000 optical links Harsh radiation environment Extensive use of commercial off-the-shelf components (COTS)

Part-of series of on-going validation tests required Part-of series of on-going validation tests required before components integrated into final systembefore components integrated into final system

Previous tests reported at SPIE and RADECS 97- 99


CMS Tracker optical link technologyCMS Tracker optical link technology

Transmitter - 1310nm InGaAsP edge-emitter Fibres and connectors - single-mode Ge-doped fibre Receivers - InGaAs p-i-n photodiode Electronics - rad-hardened 0.25m in radiation zones

COTS issues: radiation damage: up to 1014particles/cm2 + 100 kGy reliability: 10 year lifetime in radiation environment

lasers single-mode fibre + array connectors photodiodes

Tx Rx

MTMTMT


CMS ExperimentCMS Experiment


CMS Tracker radiation environmentCMS Tracker radiation environment

charged hadrons (charged hadrons (, p, K), p, K)

(courtesy M. Huhtinen, CERN)


CMS Tracker readout and control linksCMS Tracker readout and control links

PLL Delay

MUX 2:1

Timing

APVamplifierspipelines

128:1 MUX

Detector Hybrid Tx Hybridprocessingbuffering

TTCRx

ADC

Rx Hybrid

FED

TTCRx

FEC

CCUCCU

CCU CCU

DCU

Control

processingbuffering

Front-End Back-End

TTC

DAQ

Analogue Readout50000 links @ 40MS/s

Digital Control2000 links @40MHz


System specifications System specifications Analogue readout linksAnalogue readout links

specificationoperationalspecifications

min typ max unitin/out

meas

Number of channels 1 12Rise / fall time 2 nsCrosstalk min

specificationelectrical specifications

min typ max unitin/out meas

Max. input current 60 100 mAThreshold current 10 15 mAForward voltage 1.5 VReverse voltage 2 V

specificationoptical specifications

min typ max unitin/out meas

Wavelength 1260 1310 1360 nmMax output power 500 1000 µWSlope efficiency .06 W/ARelative non-linearity 1 %RIN -130 dB/Hz

Last 2 columns filled in for each device type after testing


ObjectivesObjectives

Compare damage from different particlesCompare damage from different particles 0.8MeV n and 6MeV n, 330MeV , 24GeV p, 60Co

Measure annealing characteristicsMeasure annealing characteristics Temperature and current dependence

Make prediction for damage expected in CMS trackerMake prediction for damage expected in CMS tracker 10 years at -10°C, including LHC luminosity profile


Experiment Experiment DevicesDevices

Italtel/NEC 1310nm edge-emitting InGaAsP/InP MQW lasers mounted on Si-submounts compact mini-DIL packages, single-mode fiber pigtails no other components in the package, e.g. lenses

Pre-irradiation characteristics at 20°C : Laser threshold currents 8-13mA Output efficiencies (out of the fibre) 30-70W/mA

This type of device previously studied 6MeV n, 330MeV , 24GeV p, 60Co


DCPBH-MQW lasersDCPBH-MQW lasers

double-channel-planar-double-channel-planar-buried-heterostructure buried-heterostructure laser laser


Test Procedures Test Procedures Test A: Irradiate 0.8MeV n - compare damage with other particlesTest A: Irradiate 0.8MeV n - compare damage with other particles

4 lasers, irrad room T, biased 5-10mA above threshold, 1015n/cm2 in 6.5 hrs. Anneal at room T, biased 5-10mA above threshold for 115 hrs

Test B: Irradiate 0.8MeV n - anneal at different TTest B: Irradiate 0.8MeV n - anneal at different T 12 lasers, cooled -13°C, unbiased, 1015n/cm2 in 6.3 hrs. Anneal in groups of 3 at 20, 40, 60, 80°C for 300 hrs.

Test C: Irradiate 0.8MeV n - anneal at different bias currents Test C: Irradiate 0.8MeV n - anneal at different bias currents 8 lasers, irrad room T, unbiased, 1015n/cm2 in 6.5 hrs. Anneal in groups of 2 at 0, 40, 60, 80mA bias for 115 hrs.


Test setup for in-situ measurementTest setup for in-situ measurementof radiation damage and annealingof radiation damage and annealing

MUX + DMM

I/O register

DAC

I generator

set V

Vout

Vin

photodetector

laserundertest

Mac + Labviewoptical fibre

current

Iout

signal

DataloggerUnit

Control roomIrradiationSource oroven


Test A - 0.8MeV irradiation at room TTest A - 0.8MeV irradiation at room T

Damage approximately linear with fluenceDamage approximately linear with fluence

10

8

6

4

2

0thre

shol

d in

crea

se, I

thr (

mA

)

1086420

0.75MeV neutron fluence, (1014n/cm2)

LD1 LD2 LD3 LD4


Test A - Comparison with other particlesTest A - Comparison with other particles

Relative damage factors for 0.8MeV n with respect to ~6MeVn (1/3.1), 330MeV Relative damage factors for 0.8MeV n with respect to ~6MeVn (1/3.1), 330MeV (1/11.4), 24GeV p (1/8.4).(1/11.4), 24GeV p (1/8.4).

40

30

20

10

0thre

shol

d in

crea

se,

I thr (

mA

)

543210

fluence, (1014

/cm2

)

0.75MeV n0

~6MeV n0

330MeV +

24GeV p+ Data averaged over

devices then normalized to 96 hour irradiationwith 5x1014particles/cm2.


Test B - cooled irradiationTest B - cooled irradiation

Test made at -10Test made at -10°C, then devices stored at -35C, then devices stored at -35°CC

20

16

12

8

4

thre

shol

d cu

rren

t (m

A)

4035302520151050time (hrs)

-15-10-50

T (

°C)

irrad annealing

Irradiation fluence 1015 (0.8MeV n)/cm2


Test B - Annealing versus temperatureTest B - Annealing versus temperature

Annealing generally linear with log (time)Annealing generally linear with log (time)

Devices split into4 groups of 3 andannealing at differenttemperatures.

Threshold damage assumed to be proportional to numberof defects

0.90

0.80

0.70

0.60

0.50

0.40

0.30unan

neal

ed f

ract

ion

of d

efec

ts

1 10 100annealing time (hours)

20°C 40°C 60°C 80°C


Test C - Annealing versus currentTest C - Annealing versus current

Up to factor 10 enhancement in terms of annealing timeUp to factor 10 enhancement in terms of annealing time

Irradiation to 1015n/cm2at room T, unbiased, then anneal in 4 groups of 2at different bias currents

Enhancement caused by: (i) ‘recombination enhancedannealing’ (?)- supposed to be unlikely inInGaAsP/InP

(ii) thermal acceleration dueto power dissipation. At 80mATjunction ~ 8C.

0.90

0.80

0.70

0.60

0.50

rem

aini

ng d

amag

e,

I thr(

t)/

I thr(

)

1 10 100annealing time, t (hrs)

dc bias 0 40mA 60mA 80mA


Annealing modelAnnealing model

For defects with a uniform distribution of activation energies For defects with a uniform distribution of activation energies = N/( = N/(maxmax--minmin), the ), the annealing isannealing is linear with log (time)linear with log (time)

Assume 1st order (exponential) annealing obeying Arrhenius law:

1.0

0.8

0.6

0.4

0.2

0.0

frac

tion

of

rem

aini

ng d

efec

ts, N

(,t)

/N(

,0)

108

106

104

102

100

time constant, (hrs)

1.41.31.21.11.00.90.8

activation energy, Ea (eV)

annealing time t=0.1hr t=1hr t=10hr t=100hr t=1000hr t=10000hr

A=1e-12T=20°C

kT

EexpA a

remaining fraction of defects:

de)()(N

)t(N max

min

t

where k)(N


Activation energy spectrumActivation energy spectrum

Activation energy spectrum for best fit is 0.66<EActivation energy spectrum for best fit is 0.66<Eaa<1.76eV<1.76eV

Data points for each group of 3 devices averaged.

Fit annealing model to Test B data.

0.8

0.7

0.6

0.5

0.4

0.3unan

neal

ed f

ract

ion

of d

efec

ts

1 10 100

annealing time (hrs)

A=1e-12, Ea = 0.66 to 1.76 eV

20°C 40°C 60°C 80°C fit


Damage prediction in 1yr in CMS trackerDamage prediction in 1yr in CMS tracker

32% of total defects introduced during 1 year are annealed32% of total defects introduced during 1 year are annealed

Use model to predict annealing of defects at -10°C over 1 LHC year

100

80

60

40

20

0

frac

tion

of

tota

l def

ects

in 1

yea

r (%

)

40003000200010000

exposure time (hrs)

1.00

0.95

0.90

0.85

0.80

unan

neal

ed f

ract

ion

of r

emai

ning

def

ects

100

101

102

103

104

annealing time (hrs)

LHC/CMS running LHC shutdowndamage + annealing annealing


Damage prediction 10yrs in CMS trackerDamage prediction 10yrs in CMS trackerExtend to 10 years, taking into account LHC luminosity profile

80

60

40

20

0

dam

age

(% 1

0yrs

ful

l lum

inos

ity)

1086420

LHC operating time (years)

LHC luminosity profile:

year 1: 10%year 2, 33%year 3, 66%

years 4-10, 100%

total damage annual components

Based on damage of 0.8MeV n at -10C (Test B) and relative damage factors (Test A), possible to estimate damage to laser threshold in CMS Tracker:

in worst case, at low radii (and no bias-enhancement included),

Ithr = 14mA


ConclusionsConclusions ‘‘Calibrated’ damage from 0.8MeV neutronsCalibrated’ damage from 0.8MeV neutrons

relative to 6MeV n, 330MeV , 24GeV p

Determined annealing dependenceDetermined annealing dependence temperature and forward bias current

Constructed a model to describe the annealing v TConstructed a model to describe the annealing v T uniform distribution of activation energy 0.66<Ea<1.76eV

Based on data, applied model to CMS Tracker to predict Based on data, applied model to CMS Tracker to predict laser threshold damagelaser threshold damage

In the worst case, at low radii: Ithr = 14mA

Further work:Further work: extension of the study to include lasers from other manufacturers.

radiation damage and annealing in 1310nm ingaasp/inp lasers for the cms tracker

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