performance of a si pin photodiode at low … of a si pin photodiode at low temperatures and in high...
TRANSCRIPT
Performance of a Si PIN photodiode
at low temperatures and in high magnetic
fields
Frederik Wauters*, Ilya Kraev*, Nathal Severijns*,
Sam Coeck*, Michael Tandecki*, Valentin Kozlov*,
Dalibor Zákoucký**
*Katholieke Universiteit Leuven (Belgium)
**Nuclear Physics Institute, Rez (Czech Republic)
Overview
• The detector and it’s usage• General properties
• Tests towards the use in a LTNO setup
• High field measurements• Round up
• Future plans
The detector and it`s usage
Si PIN photodiode:
A p-i-n junction working as a 500 µm think window-less Si detector.
Type: S3590-6
from H
AM
AM
ATSU
Si PIN photodiode:
A p-i-n junction working as a 500 µm think window-less Si detector.
• Light detection
The detector and it`s usage
• Read out of scintillators
• ! Light level has to be
high enough
* Datasheet Hamamatsu
*
Type: S3590-6
from H
AMAM
ATSU
Si PIN photodiode:
A p-i-n junction working as a 500 µm think window-less Si detector.
• Light detection
The detector and it`s usage
• X-ray detection
*
*Datasheet Hamamatsu** Y. Inoue et al NIMA 368 (1996) 556-558
**
• High efficiency for low
energy`s (< 10 keV)
• ! Noise threshold
Type: S3590-6
from H
AMAM
ATSU
Si PIN photodiode:
A p-i-n junction working as a 500 µm think window-less Si detector.
• Light detection
The detector and it`s usage
• X-ray detection
*
*Datasheet Hamamatsu** Y. Inoue et al NIMA 368 (1996) 556-558
** • α-ray detection
• Thin front dead
layer
• ! Radiation damageType: S3590-6
from H
AMAM
ATSU
Si PIN photodiode:
A p-i-n junction working as a 500 µm think window-less Si detector.
• Light detection
The detector and it`s usage
• X-ray detection
*
*Datasheet Hamamatsu** Y. Inoue et al NIMA 368 (1996) 556-558
** • α-ray detection
• electron detection
• Fully stop
energy`s
< 350 keV
• Low
background
from high
energy γ`s
60Co
Type: S3590-6
from H
AMAM
ATSU
Si PIN photodiode:
A p-i-n junction working as a 500 µm think window-less Si detector.
• Light detection
The detector and it`s usage
• X-ray detection
*
*Datasheet Hamamatsu** Y. Inoue et al NIMA 368 (1996) 556-558
** • α-ray detection
• electron detection
• Fully stop
energy`s
< 350 keV
• Low
background
from high
energy γ`s
60Co
Type: S3590-6
from H
AMAM
ATSU
General properties
• 9 x 9 mm active area
• 500 µm depletion layer thinkness• Maximum reverse bias : 150 V• Low capacitance and leakage current(relative to other photodiodes)
• Spectral response max. at 980 nm
General properties
• 9 x 9 mm active area
• 500 µm depletion layer thinkness• Maximum reverse bias : 150 V• Low capacitance and leakage current(relative to other photodiodes)
• Spectral response max. at 980 nm
Dark current drops fast with decreasing temperature
Even a little bit of cooling can decrease the detector noise
General properties
• 9 x 9 mm active area
• 500 µm depletion layer thinkness• Maximum reverse bias : 150 V• Low capacitance and leakage current(relative to other photodiodes)
• Spectral response max. at 980 nm
The insensitive surface layer (SiO2)
was measured with α-particles:
0,35 µm ± 0,02 µm *
* Y. Atimoto et al., NIMA 557 (2006) 684-687
*
Important for measurements with
α-particles and low energy X-rays
General properties
• 9 x 9 mm active area
• 500 µm depletion layer thinkness• Maximum reverse bias : 150 V• Low capacitance and leakage current(relative to other photodiodes)
• Spectral response max. at 980 nm
The surface of a simular PIN diode was scanned with a 2 MeV He microbeam:Good charge collection efficiency at the center of the detector but satellite peaks and other unwanted effect`s at the edges.**
** A. Simon et al., NIMB 231 (2005) 507-512
**
Collimator
Tests towards the use in a LTNO setup
Requirements: • Sensitive for α- and β-radiation but not to sensitive for γ`s.High energy γ`s generate an unwanted comptonbackground.
• Be able to work close to 4K.• Be able to work in magnetic fields up to 0,5 T
Standard setup:
Vacuum chamber/
cryostat
Pre-amplifier
(Canberra 2003)
Shaping
amplifierADC
DAQ
PC
On the scope
1 or 2 µsshaping time
Tests towards the use in a LTNO setup
Requirements: • Sensitive for α- and β-radiation but not to sensitive for γ`s.High energy γ`s generate an unwanted comptonbackground.
• Be able to work close to 4K.• Be able to work in magnetic fields up to 0,5 T
αααα`s and ββββ`s at room temperature:207Bi source
482 keV(K line)
554 keV & 566 keV
(L & M line)
976 keV
(K line)
PulserX-rays
Resolution: 6,5 keV 7,1 keV
Noise threshold at 23 keV
Typical resolution at 6 MeV is 20 keV,
best is 14 keV.
Tests towards the use in a LTNO setup
Requirements: • Sensitive for α- and β-radiation but not to sensitive for γ`s.High energy γ`s generate an unwanted comptonbackground.
• Be able to work close to 4K.• Be able to work in magnetic fields up to 0,5 T
αααα`s and ββββ`s at room temperature:
482 keV
(K line)207Bi measurendwith different bias
voltages
From 30 V on, no big changes in the
peakshape.Standard bias: 140 V
Tests towards the use in a LTNO setup
Requirements: • Sensitive for α- and β-radiation but not to sensitive for γ`s.High energy γ`s generate an unwanted comptonbackground.
• Be able to work close to 4K.• Be able to work in magnetic fields up to 0,5 T.
From room temperature to 77 K to close to liquid helium temperature :
Liquid nitrogen
Room
temperature
Liquid helium
& 0,5 T
Tests towards the use in a LTNO setup
Our conclusions until now:
• The detector showed good behaviour close to 4 K and in a field up to 0.5 T
β-asymmetry measurements
with 60Co
Half-life measurements of
α-emittors at low temperatures in
metals
Tests towards the use in a LTNO setup
Our conclusions until now:
• The detector showed good behaviour close to 4 K and in a field up to 0,5 T• We can reproduce spectra with Monte-Carlo simulations (GEANT4)
Tests towards the use in a LTNO setup
Our conclusions until now:
• The detector showed good behaviour close to 4 K and in a field up to 0,5 T• We can reproduce spectra with Monte-Carlo simulations (GEANT4)
• Resolution between two detectors can differ by ± 1keV• Peformance can go down in time
Radiation damage
Temperature cycles
Tests towards the use in a LTNO setup
Our conclusions until now:
• The detector showed good behaviour close to 4 K and in a field up to 0,5 T• We can reproduce spectra with Monte-Carlo simulations (GEANT4)
• Resolution between two detectors can differ by ± 1keV• Peformance can go down in time
• The detector is quite sensitive to vibrations (LN2 filling)• Bringing the unamplified signal outside the setup is not optimal
→ noise
High field measurements
The behaviour of the detector in magnetic fields up to 11 T
was tested to investigate the possibility to use this detector in an ion-trap.
What is already know? • An Avalanche PhotoDiode (APD) is not affected by fields up to 7,9 T*.
• Silicon drift detectors work well in fields up to 4,7 T**. The position
resolution can be retained by tuning the angle between the detector and
the incident particles***.
* J. Marler et al., NIMA 449 (2000) 311-313** S.U. Pandey et al., NIMA 383 (1996) 537-546*** A. Castoldi et al., NIMA 399 (1997) 227-243
High field measurements
The behaviour of the detector in magnetic fields up to 11 T
was tested to investigate the possibility to use this detector in an ion-trap.
B
• Field ⊥ PIN diode• In high fields e± with energy`s that can be fully stopped by the detector
follow the field lines• More particles at grazing incidence
• The performance of the PIN diode was measured in different magnetic
fields:0 T, 0,5 T, 2 T, 5 T, 7 T, 9 T, 11 Tthis over a period of two weeks.
High field measurements
Experimental setup
77 K
4 K
Room temperature
shield
Superconduction
magnet up to 17 T
Source (207Bi/57Co)
PIN diode
Usual position of
the detector
Charge sensitive
pre-amplifier
Amplifier
ADC
DAQ
High field measurements
General conclusion:
• The detector still works even in a magnetic field up to 11 T.
• The performance of the detector after the field measurent did not go down.
High field measurements
General conclusion:
• The detector still works even in a magnetic field up to 11 T.
• The performance of the detector after the field measurent did not go down.
! BUT !
this is not the whole story
High field measurements
Resolution (FWHM) ?
Reference at 0 T: • 8,2 (3) keV for 481 keV• 9,7 (6) keV for 975 keV
High field measurements
Resolution (FWHM) ?
Reference at 0 T: • 8,2 (3) keV for 481 keV• 9,7 (6) keV for 975 keV
not ideal
Noise conditionsor/and
the detector ?
High field measurements
Resolution (FWHM) ?
Reference at 0 T: • 8,2 (3) keV for 481 keV• 9,7 (6) keV for 975 keV
For 0,5 T: • 10,4 (3) keV for 481 keV• 11,4 (5) keV for 975 keV
High field measurements
Resolution (FWHM) ?
Reference at 0 T: • 8,2 (3) keV for 481 keV• 9,7 (6) keV for 975 keV
For 0,5 T: • 10,4 (3) keV for 481 keV• 11,4 (5) keV for 975 keV
In higher fields the resolution is on average ca. 1 keV worse
Time (arb units)
Resolu
tion (
arb
units)
0,5 T
11 T
High field measurements
Resolution (FWHM) ?
Reference at 0 T: • 8,2 (3) keV for 481 keV• 9,7 (6) keV for 975 keV
For 0,5 T: • 10,4 (3) keV for 481 keV• 11,4 (5) keV for 975 keV
In higher fields the resolution is on average ca. 1 keV worse
Resolution sometimes changed with 1 or 2 keV
→ No 1 to 1 relation with the size of the field→ Clear correlation between the resolution and the noise level
High field measurements
Ghost peaks
419 keV
863 keV
1139 keV
1263 keV
1539 keV
1628 keV
2031 keV
Trapped charges?
Do not go away by lowering the field (or powering down the
detector).We measured at 11 T without this
effect.At 2 T they appeared after 11 hours without clear reason.
→ No clear relation with the size of the field.
High field measurements
Ghost peaks
Trapped charges?
Do not go away by lowering the field (or powering down the
detector).We measured at 11 T without this
effect.At 2 T they appeared after 11 hours without clear reason.
→ No clear relation with the size of the field.
When they dissappeared it always could be linked to some
manipulation of the setup.(Filling of the cryostat which
gives strong vibrations)
There is a clear correlation between the noise level and this
effect.
Round up
• The silicon PIN photodiode is a suitable detector
for α and β particles.• Works well at 4 K and ca. 0,5 T
• It survives and works at high magnetic fields up to11 T
• BUT
• Low cost alternative to other solid state particledetectors
Trapped charges? → Forward bias
Future plans
• Test an IC pre-amplifier to reduce noise pick-up
between between the detector and thepre-amplifier and try to cool it together with the
detector• Read out a scintillator and scintillating fiber with a
a photodiode (and maybe switch to an APD).
• More field tests