Hamburg University: Plans for SLHC Silicon Detector R&D Georg Steinbrück Wien Feb 20, 2008.
Transcript of Hamburg University: Plans for SLHC Silicon Detector R&D Georg Steinbrück Wien Feb 20, 2008.
Hamburg University:Plans for SLHC Silicon Detector
R&DGeorg Steinbrück
WienFeb 20, 2008
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Plans for SLHC Silicon Detector R&D
• Projects and collaborations of the group
• Strategies
• Measurements of material properties
• Sensor simulation/optimization
• Simulation of detector performance
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Projects and Collaborations of the Group
• The group is involved in the following Projects with respect to Detector R&D:
• LHC (funded by BMBF)
• HGF-Alliance (17 German Universities + DESY + FZK) “Physics at the terascale”
• WP1: The Virtual Laboratory for Detector Technologies
• WP2: Detector R&D Projects
• HPAD-XFEL (with Bonn, PSI, DESY)
• Approved. Project started.
• PAD-Marie Curie (with CERN, DESY, …) “Marie Curie Training Network on Particle Detectors”
• Approved in principle. Contract negotiations with EU.
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Strategies
Study of macroscopic properties:
IV, CV, TCT (transient current technique)
Study of microscopic properties: Defects DLTS: deep level transient spectroscopy, TSC: thermally stimulated current method)
Neff, I, e,h :f(Doping, t, radiation dose, …)Sensor simulation/ optimization:
E, I, C as a function of irradiation, material
Simulation of charge collection in detector , spatial resolution, reconstruction
Monte Carlo
•simulation
•experiment: -multi-TCT -testbeam
detector
= dE/dx x sensor x FE electronics
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Examples Material Properties
0 2.1015 4.1015 6.1015 8.1015 1016
eq [cm-2]
0.0
1.0.1014
2.0.1014
3.0.1014
Nef
f(t0)
[cm
-3]
0
100
200
300
400
500
600
Vfd
(t0)
[V
] no
rmal
ized
to 5
0 m
25 m, 80oC25 m, 80oC
50 m, 80oC50 m, 80oC
50 m, 60oC50 m, 60oC
23 GeV protons23 GeV protons
0 2.1015 4.1015 6.1015 8.1015 1016
eq [cm-2]
0
5.1013
1014
Nef
f (t 0
) [cm
-3]
0
50
100
150V
fd (
t 0)[
V]
norm
aliz
ed to
50 m
50 m50 m
25 m25 m
Reactor neutronsReactor neutrons
Ta = 80oCTa = 80oC 0 2.1015 4.1015 6.1015 8.1015 1016
eq [cm-2]
0
50
100
150
200
250
Vfd
[V
]
50 m simulation50 m simulation
50 m after 50 min@80C annealing50 m after 50 min@80C annealing
25 m simulation25 m simulation
25 m after 50 min@80C annealing25 m after 50 min@80C annealing
SLHC operating scenario, measurement compared to simulation: “Hamburg Model”
Thin n-type epi-Silicon. No space charge sign inversion after proton and neutron irradiation.
Explanation: Introduction of shallow donors overcompensates creation of acceptors.
More pronounced in 25µm Si due to higher oxygen concentration.
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rad. induced acceptors in lower half of band
gap: neg. charged, neg. space charge hole traps (H). Increase with annealing time neg. space charge increases, Neff decreases!
conduction band
valence band
1 10 100 1000 10000-5.0x1012
0.0
5.0x1012
1.0x1013
1.5x1013
2.0x1013
2.5x1013
3.0x1013
3.5x1013
MCz Neff at RT Nd - [H116K] - [H140K] - [H152K]
Co
nce
ntr
atio
n (
cm-3)
Annealing time at 800C (minutes)
EPI-DO Neff at RT Nd - [H116K] - [H140K] - [H152K]
EPI-ST N
eff at RT
Nd-[H116K]-[H140K]-H[152K]
Study of Microscopic Defects: Thermally Stimulated Current
(TSC)Neff
0 20 40 60 80 100 120 140 160 180 2000
10
20
30
40
50
60
70
80
90MCz
H(140K)
BD+/++
IO2
-/0
VO
V2+?
H(152K)
H(116K)
BD0/++
E(35K)
E(28K)
H(40K)
TS
C s
igna
l (pA
)
Temperature (K)
Forward injection at 5K, RB=300V as irradiated 20min@80C 80 min@ 80C 320min@80C 1370min@80C 34270min@80C
TSC results for fully depleted diodes.Goal: Identification of defects
responsible for long term annealing(“reverse annealing“) of Neff. VFD
Difference ND-H und Neff: VP
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Simulation of Detector Performance, Comparison with Test Beam Data
Example testbeam measurement for
irradiated CMS sensors
integrated (PH(R)/PH(L)+PH(R)) versus
for various incidence angles.
Example simulation:
Reconstructed position versus reduced incidence position on strip.
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Simulation of Charge Clouds
electron cloudhole cloud
Front
Backside
structure (strip/pixel)
Bias-Voltage Vbias
t2
t2
t1
t1
t0
I1 I0
Current is induced to all strips
Readout of current allows to investigate charge cloud distribution
I0 current on closest strip
I1 current on neighboring strip
black: sum of both strips
e collected
h collected
Goal: Study the effects of trapping.
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Verification with Multi Channel TCT
attenuator + amplifier
Laser
optics
z table
x-y stagetemporary detector support
Goal: Time-resolved measurement of charge collection in Si-pixel and strip detectors in multiple channels up to very high charge densities. fine-grain position and angle scans.
Multi-TCT under construction in Hamburg:
• ps laser (1052 nm and 660 nm), <90ps, Wmax~200pJ, spot size <10 µm (red)
• penetration depth 3 µm (red), 1000µm (IR)
• fast amplifiers (miteq)
• data acquisition with fast oscilloscope (500 MHz, 1GS/channel), possible upgrade to digitizer cards with up to 20 ch, synchronized
• cooled detector support (Peltier)
10 ns
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People
• Doris Eckstein (main Hamburg contact person)
• Robert Klanner
• Peter Schleper
• Georg Steinbrück
• Eckhart Fretwurst (defect engineering)
• Julian Becker, PhD student (multi-TCT)
• Volodymyr Khomenkov (starting ~March) (Detector simulation)
• Ajay Srivastava (just started) (sensor simulation: TCAD,…)
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Backup
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Schematic set-up of the Multi-TCT
optic fiber and optics
working distance
optic axis (z)
z
x
y
laser and driver
Oscilloscopeattenuators and amplifiers
bias voltage supply, leakage and guardring current measurement
PID temperature controller
trigger line
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Laser system (PicoQuant)
660 nm (red)• minimum energy:
1 mip 10 x XFEL /pulse 70 ps pulse width
• maximum energy: 140 pJ/pulse 4x104 XFEL-/pulse 100 million e-h pairs 4000 mips 800 ps pulse width
1052nm (infrared)• minimum energy:
1 mip 10 x XFEL /pulse 70 ps pulse width
• maximum energy: 275 pJ/pulse 4x104 XFEL-/pulse 100 million e-h pairs 4000 mips 700 ps pulse width
Gaussian beam after single mode fiber
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Laser system (red)
maximum energy: 140 pJ/pulse 800 ps pulse width
minimum energy: 22 pJ/pulse 70 ps pulse width
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Laser system (IR)
minimum energy: 44 pJ/pulse 70 ps pulse width
maximum energy: 275 pJ/pulse 700 ps pulse width