Detector developments and investigation of radiation damage in semiconductor detectors in the

Institute of Nuclear Research of HAS (ATOMKI), Debrecen

Gabor Kalinka

Semiconductor detector development between 1971-90 concentrated around Si(Li) X-ray detectors and complete X-ray spectrometers. Nowadays - in collaboration with Japanese partners - Si pin and SDD detectors, and HgI2planar detectors, all for X-ray detection, are under construction.

Scintillation charged particle detector systems using CsI(Tl) crystals coupled to Si pin photodiodes has been developed for nuclear physics (European, Japanese and South-African collaborations), while systems using LSO/LYSO crystals combined with Position Sensitive Photoelectron Multipliers are being developed for gamma-ray detection in Positron Emission Tomography (PET).

Detector radiation damage studies started very recently in ATOMKI with the increased use of Si pin photodiodes in conjunction with particle accelerators.

Semiconductor detector developmentionizing radiation: e-h pair creation in reverse biased diode structures,

charge collection, integration, signal shaping (noise filtering), amplitude measurement

P-N detectorThin sensitive volume:• low X/gamma efficiency• large capacitance → noise

P-I-N detector, e.g. Si(Li)Thick sensitive volume:• higher efficiency• lower capacitance• better energy resolution

X-ray spectrometer developed at ATOMKI between 1971-1980 : Si(Li) detector, liquid nitrogen cooling, pulsed drain feedback preamplifier, time variant (1980) and digital (1989) signal processing150 eV FWHM , ~80 units sold between 1978-1992 to COMECON countries

High vacuum dewar Si(Li) detectors (1988)in cooperation with Tesla, Brno (Czechoslovakia)

ATOMKIDebrecen

1986: XRF laboratory, Havanna

1990: Detector laboratory, Osaka

1991: end of Si(Li) era, ATOMKI“detector clinics”

136 eV FWHM

Microelectronics: advanced p-n or p-i-n detector (photodiode)3-4 orders of magnitude (!) lower current → moderate cooling

~ 100-800 µm thickness, X-ray energy 1-20 keVGood Si(Li) detectors have still been the standard!

Hamamatsu S1223 photodiode

2.4 x 2.8 x 0.2 mm3

Room temperature X-ray detectionwith Si-pin photodiodes

S58af6.spm (1551.17 - 7330.02)

Energie

Con

tenu

s de

cana

ux

1600 2100 2600 3100 3600 4100 4600 5100 5600 6100 6600 7100

2357

10

2030

5070

100

200300500700

1000

20003000

50007000

FWHM=440 eV @ 5.9 keV FWHM=580 eV @ 60 keV

Fe-55 Am-241

Semiconductor Drift Detector (SDD)1984, Gatti, Rehakvery small anode, very small capacitance, excellent resolution

Principle of the sideward depletion

N+ N P+

Partial depletion

Full depletion

Realization of a circular drift detector

AMPTEK (USA) pin detector-30 oC, 150 eV, 3000 USD

KETEK (Germany.) drift-detector -30 oC, 125 eV, 10000 EU

Aim: construction of similar pin/SDD detector unitsInternational collaboration with Osaka Electro-Communication University and a Japanese Semiconductor Company

Prototype Si pin/SDD detector(radiation entrance side)

HgI2 detector development

single crystal from Constellation Technology, Florida50 mm2 area, 1 mm thickness

- HV side irradiation + HV side irradiationElectron traversal Hole traversal

Scintillation detector developments (1991-) - CsI(Tl) scintillator (550 nm) + Si pin photodiodes- LSO scintillator (420 nm) + PMT

Scintillation charged particle detector systems developed by ATOMKIusing multilayer polymer mirror reflector wrapping based on

Giant Birefringent Optics

100 element CsI(Tl) + Si pin photodiode detector system (DIAMANT + ChessBoard) for EUROBALL, (France, Italy)EXOGAM (Ganil, France) AFRODITE (iThemba, South Africa)Collaboration with CENBG, Bordeaux; MSI, Stockholm; INFN, Napoliscintillator : 14 x 14 x 3 mm3

photodiode : 10 x 10 mm2

for ~ 30 MeV/ amu particlesDedicated preamplifiers and highly integrated dedicated electronics in VXI-standardExcellent energy- and particle-resolution (~ 2 times better than that of counterpart Microball at Gammasphere)

300 element CsI(Tl) + Si pin photodiode detector system (GRACIA) for RIBF at RIKEN (Japan)Collaboration with Riken and Rikkyo Universityscintillator : 16 x 16 x 55 mm3

photodiode : 10 x 10 mm2

for ~ 130 MeV/ amu particlesDedicated preamplifiers, (yet) standard signal processing electronicsPerformance is only a little bit inferior to the DIAMANT system (det. size 24x larger !)

The DIAMANT charged particle detector system built into the target chamber of the EUROBALL gamma-detector system (Strasbourg, 2004)

The electronic units for processing scintillation detector signals synchronously with Germanium detector signals has also been developed in ATOMKI (not shown in the photo).

The forward hemisphere of DIAMANT detector system together with mounted preamplifiers inside the target chamber

Energy resolving capability of DIAMANTscintillationdetectors (low energy alpha spectrum of U-232)

Particle resolving capability of DIAMANT scintillation detectors (low energy region < 50 MeV)

Particle Energy (arb. unit)

PROTONS

EUROBALL + DIAMANT with VXICommissioning Experiment; April 2000

170Er + 30Si (165 MeV)

DEUTERONS

ALPHAS

Pulses from PIN-diodes

Part

icle

Typ

e

Part of the 300 element (detectors packed in quad units) CsI(Tl)+Si pin photodiode charged particle detector system GRACIA at RIKEN RARF

Detector blocks for small animal PET systems

• Crystal type: LSO scintillator• Crystal size: 2X2X10 mm3

• 8x8 crystal matrix unit• Lumirror light reflector• Position Sensitive PhotoMultiplier Tube• Recently: 33x33 matrix unit of

1.4x1.4x12.5 mm3 LYSO crystals16x16 anode PSPMT

Radiation damage researchDetector radiation damage studies started very recently in ATOMKI with the increased use of Si pin photodiodes in conjunction with particle accelerators. Preliminary results has been obtained with 5.5 MeValpha particle irradiation from Am-241 isotope, with 6.5 MeV oxygen, 2.15 MeV lithium, 0.43 MeV hydrogen ions (both with 5 um range in Si), and 2 MeV protons (50 um range). Photodiodes irradiated uniformly were characterized by I-V and C-V techniques and charge collection measurements with 5.5 MeV alpha particles. Diodes irradiated with a patterned way were evaluated with Ion Beam Induced Charge (IBIC) method, using µm focussed beam of the same particle at the same energy as during irradiation either online or offline.

10-4 10-3 10-2 10-1 100 101 10210-2

10-1

100

101

102

103

104

105

Reverse bias voltage [V]

Leak

age

curre

nt [p

A]

S5821 diode at 22 degrees centigrade

Summary of I-V plots versus 5.5 MeV alpha fluenceup to 1x1011 cm-2 (generation centers)

Leak

age

cur

rent

[pA

]]

C-V plots versus fluence of 5.5 MeV alpha(ionized impurity centers)

10-2 100 102100

101

102

Reverse bias voltage [V]

Cap

acita

nce

[pF]

S58F diode irradiated by 0/0.05/1.05*10^11/cm2 5.5 MeV alpha

D

biRS

NUU

qW )(2 +

=ε

WAC Sε=

if Nd= const.

virgin

5x109 cm-2

1x1011 cm-2

Cap

acita

nce

[pF]

CCE measurement with 5.5 MeV alpha particles after different fluences of 5.5 MeV alpha particles

(trapping and/or recombination centers)

0 0.2 0.4 0.6 0.8 15350

5400

5450

5500

1/(Reverse bias voltage) [1/V]

Pea

k am

plitu

de [k

eV]

S58F diode measured with Am241 alpha following Am241 irradiation

virgin

5x109 cm-2

1x1011 cm-2

Pea

k am

plitu

de [k

eV]

2 MeV H+ irradiation (50 µm range) of 3x3 squares of 100x100 µm2 area in logarithmically evenly spaced fluence steps from 0 to 5x1011 cm-2

0 50 100 150 200 250 3000

50

100

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100150

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x 104

Before @ Ud=0 V

After @ Ud=0 V

2 MeV H+ IBIC scan of the irradiation site prior to irradiation at Ud=0 V

Detector material nonuniformity (growth striations)

0.61

0.615

0.62

0.625

0.63

0.635

0.64

0 50 100 150 200 250 3000

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100

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0.61

0.615

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0.625

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0.635

0.64

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0100

200300

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Results relevant for detector applications: degradation for the Ud ≥ 10 V case

0.01 0.1 1 10

-2.0

-1.8

-1.6

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-0.4

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0.0

Rel

ativ

e A

mpl

itude

Shi

ft (%

)

Fluence (1011 ion/cm2)

10V 20V 50V 100V

0.01 0.1 1 1010

11

12

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FWH

M (k

eV)

Fluence (1011 ion/cm2)

10V 20V 50V 100V

][][][10)5.03.3(][][10)5.02.2()(

22132215

VUcmVcmcmcmCCE rad

−−−− Φ

×±−+Φ×±=δ

][][

10)5.10.4(][2

5

VUcm

keVrad

−− Φ

×±=∆ 220 rad∆+∆=∆