Transcript Document

CBM Silicon Tracking System.
Results of the pre-prototype
detector module test.
V.M. Pugatch
Kiev Institute for Nuclear Research
Thanks to coauthors:
M. Borysova J.M. Heuser 2, O. Kovalchuk 1, V. Kyva 1,
A. Lymanets 1,3, V. Militsiya 1, O. Okhrimenko 1, A. Chaus1,
B. D. Storozhik1, V. Zhora 4, V. Perevertailo 4,
C. Galinskiy 5
1,
1
KINR, Kiev
Darmstadt,
3 now at FIAS, J.W. Goethe University, Frankfurt,
4 Institute of Microdevices (Kiev)
5 SPA AEROPLAST (Kiev)
2 GSI,
V. Pugatch
CBM Collaboration
Meeting, Dubna, Oct. 13-17 2008
1
R&D: Agreement ‘KINR-GSI’
• A low-mass mechanical assembly of
double-sided silicon microstrip sensors
and their connection through analog
readout cables to a readout electronics
• construction of an experimental test
stand
• A quality assurance procedure suitable
for a future larger detector module
production.
V. Pugatch
CBM Collaboration
Meeting, Dubna, Oct. 13-17 2008
2
Prototype for evaluations: LHCb
Silicon Tracker – supporting boxes
with cooling pipes
Negotiations are in progress wrt involvement
into the Detector Module Cooling activity
of joint German-Ukrainian venture
Labor-Technik LTD
www.labor-technik.com.ua
V. Pugatch
CBM Collaboration
Meeting, Dubna, Oct. 13-17 2008
Cooling infrastructure
and temperature
monitoring for the CBM
detector module - design
at the AEROPLAST
(Kiev).
Cooling inside of the
supporting ladders …
3
ASSEMBLY
of the Module prototype
• 1st prototype – the
design similar to the
long ladders of the
LHCb Silicon
Tracker – modified
for the double-sided
version of sensors
V. Pugatch
CBM Collaboration
Meeting, Dubna, Oct. 13-17 2008
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Prototype Module
assembly scheme
Separated heat flow by making different supporting frames :
- for hybrids with readout chips
- for Si-sensor (to prevent heating of the sensor)
V. Pugatch
CBM Collaboration
Meeting, Dubna, Oct. 13-17 2008
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Supporting frame
A low mass module- to minimize multiple Coulomb-scattering of charged particles in the
detector and support materials.
• AEROPLAST(Kiev) –
design and production:
Three-layer frames
composed by two flat plates
(0.25 mm thick) with foam layer
(1 mm thick, density - 0.7 g/cm3)
in between
three types
to match the sizes of prototype
silicon sensors
CBM01, CBM01-B1, CBM01-B2 .
V. Pugatch
CBM Collaboration
Meeting, Dubna, Oct. 13-17 2008
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Microcables for the discrete electronics
readout
Side A:
Connecting
by ultrasonic bonding
to sensors
4 Different cables were needed
for every type of the sensors:
In total, 16 types cables were designed
and produced
Side B: Connecting by soldering to preamplifiers
V. Pugatch
CBM Collaboration
Meeting, Dubna, Oct. 13-17 2008
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Microcables for the discrete electronics
readout
CBM01-B2-sensor
50,7 μm – pitch
Double-sided
Sensor is glued to the AEROPLAST
Carbon fiber supporting frame
Microcables are bonded to sensor pads:
Even strips – to one side;
odd strips to the opposite side
LEMO connectors are soldered
by wires to large pads on microcables
V. Pugatch
CBM Collaboration
Meeting, Dubna, Oct. 13-17 2008
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Micro-cables suitable for connecting sensors
and n-XYTER microchip
A double-layer micro cable
• 25 µm wide, 20 µm thick Al strips
• 101.4 µm pitch
• on 24 µm thick polyimide film
has been designed and produced at the
Institute of Microdevices (IMD, Kiev).
Different cables of that type have been
tested
using
them for the CBM01 (50 x 50 mm2 ) sensor
readout by a discrete electronics
V. Pugatch
CBM Collaboration
Meeting, Dubna, Oct. 13-17 2008
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Cooling infrastructure
Thermo-isolating box shielded against r/f
pick-up has been designed and built.
Thermo sensors (two types)
• Pt-100
• Institute of Microdevices (Kiev) production (based on
microcable technology)
were installed to monitor temperature at different areas of the
detector module
V. Pugatch
CBM Collaboration
Meeting, Dubna, Oct. 13-17 2008
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Cooling infrastructure
Cooling studies
V. Pugatch
CBM Collaboration
Meeting, Dubna, Oct. 13-17 2008
11
Cooling infrastructure
Thermo-mechanical tests with dummy silicon samples glued by silicon glue onto
the supporting frames:
•
•
•
perfect mechanical rigidity for all supporting frames but one
thermo-conductivity appr. 0.6 W/m*deg in the longitudinal direction
A special design has been developed for investigating cooling by circulating a
liquid agent in hollow plates. Currently such structure didn’t show needed
mechanical stability. It might be improved at the price of increasing the transversal
size of the frame up to 5 mm (keeping material budget still within a required 0.3
X0 ).
•
Negotiations with joint German-Ukrainian venture Labor-Technik LTD
www.labor-technik.com.ua
V. Pugatch
CBM Collaboration
Meeting, Dubna, Oct. 13-17 2008
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Sensors characterization
• The first detector module prototypes equipped with CBM01B1,
CBM01B2 as well as CBM01 sensors have been mounted and
connected to a discrete electronics at the readout board.
• Tests are performed at KINR using laser pulses (640 nm) and
radioactive sources.
V. Pugatch
CBM Collaboration
Meeting, Dubna, Oct. 13-17 2008
13
Sensors characterization
•Mounting sensors on
Supporting AEROPLAST frame
•Connecting p-, and n-strips
by microcables to LEMO
connectors – inputs to PA
V. Pugatch
CBM Collaboration
Meeting, Dubna, Oct. 13-17 2008
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Measurements with radioactive sources
Ra-226, 4 lines – alpha-source.
Charge, Strip ” k”
Test setup at KINR:
coincident energy spectra
for pairs of adjacent strips
Interstrip gap data
strips functionality
charge sharing
full depletion voltage
Charge, Strip “k+1”
Irradiation in two steps:
1. from p-side (4-lines structure should be clearly pronounced
at any allowed depletion voltage)
2. from n-side (4-lines structure should appear at full depletion
voltage)
V. Pugatch
CBM Collaboration
Meeting, Dubna, Oct. 13-17 2008
15
Measurements with radioactive sources
CBM01-B1-sensor
226 Ra
80 μm – pitch,
from p-side, p-strips read-out, HV 0 – 50 V
Unexpected performance !
Illustrates problem
with electric field
in the interstrip gap
V. Pugatch
CBM Collaboration
Meeting, Dubna, Oct. 13-17 2008
16
Measurements with radioactive sources
CBM01-B1-sensor
226 Ra
80 μm - pitch
from n-side,
HV = 10 V
Non-depleted sensor,
N-strips are shortened
(events along the diagonal)
HV = 30 V
Approaching full depletion voltage …
Yet! There was never clear separation
of events belonging to 4 alpha-lines :
Thick (10 -15 μm) dead layer from n-side ?
V. Pugatch
CBM Collaboration
Meeting, Dubna, Oct. 13-17 2008
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Interstrip gap –
charge collection efficiency low ?
• Depletion Voltage
0V
4V
Coincident spectra of adjacent strips
V. Pugatch
CBM Collaboration
Meeting, Dubna, Oct. 13-17 2008
4V
Single strip spectrum
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Measurements with radioactive sources
Sr-90 – β-source (selecting its MIP part).
MIP – trigger (high energy tail in PM-2)
Measuring PM – Si-strip coincidences.
Sr - 90
PM-1
Si-det.
РС –
interface
PC
Pentium
1200
MHz
PM-2
Test Setup at KINR
Measure Landau MIP peak
(for p- as well as n-strips)
as a function of depletion voltage:
Determine full depletion voltage
V. Pugatch
CBM Collaboration
Meeting, Dubna, Oct. 13-17 2008
19
Measurements with radioactive sources
90Sr – β-source (CBM01-B2 sensor)
d00.126: Si-strip Component, 10 V
• p-strip MIP-spectra
1600
Threshold = 0
Threshold = 10
Threshold = 30
1400
1200
1000
Events
25
800
MIP peak - 10
MIP Position, Channel
600
th
channel
400
20
200
0
0
10
20
30
40
50
Channel Number
15
60
70
80
d00.124: Si-strip Component, 30 V
450
Threshold = 0
Threshold = 10
Threshold = 40
400
10
350
20
30
40
50
Voltage, V
60
70
80
MIP-spectra have nice Landau-shape at low
depletion voltage,
while at higher than 30 V
the noise makes it gaussian-like one.
300
Events
10
250
MIP peak - 16th channel
200
150
100
50
0
0
10
V. Pugatch
CBM Collaboration
Meeting, Dubna, Oct. 13-17 2008
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30
40
50
Channel Number
60
70
80
20
Measurements with radioactive sources
90Sr – β-source (CBM01-B2 sensor)
• n-strip MIP-spectra – non Landau shape – noise from
d00.141: Si-strip
Component,
80 V
high leakage current
smears
spectrum
400
Threshold = 0
Threshold = 20
Threshold = 40
350
300
Events
250
200
MIP peak - 21st channel
150
100
50
0
0
10
20
30
40
50
Channel Number
60
V. Pugatch
CBM Collaboration
Meeting, Dubna, Oct. 13-17 2008
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80
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Laser test setup
LHCb Laser setup
at Zurich University –
Measuring in atmosphere
V. Pugatch
CBM Collaboration
Meeting, Dubna, Oct. 13-17 2008
22
Laser test setup at KINR
V. Pugatch
CBM Collaboration
Meeting, Dubna, Oct. 13-17 2008
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Laser test setup
CBM01 sensors test results
Interstrip gap is irradiated by focused laser beam.
Coincident spectra at different depletion voltage from n –side allow determination
of full depletion voltage.
Notice: linear response exists at very narrow central part of the interstrip gap –
-close to 5 μm, only - Necessity to measure precisely η-function – for improving hit
position resolution
V. Pugatch
CBM Collaboration
Meeting, Dubna, Oct. 13-17 2008
24
Laser test setup at KINR
4th year students from
Kiev University –
Measuring η-function
For the CBM-01 sensor
V. Pugatch
CBM Collaboration
Meeting, Dubna, Oct. 13-17 2008
25
Laser test setup at KINR
Laser spot moving
from one
strip to another one
also changing
a spot brightness
V. Pugatch
CBM Collaboration
Meeting, Dubna, Oct. 13-17 2008
26
Laser test setup at KINR
Analog signals
from adjacent strips –
Laser spot appr.
at the middle
of the interstrip gap
V. Pugatch
CBM Collaboration
Meeting, Dubna, Oct. 13-17 2008
27
Laser test setup at KINR
Analog signals
From adjacent stripsLaser spot is close to one of
the strips (large amplitude)
-Negative pulse at another
strip – reason unknown
Plan to check
whether this
happens also
for particles
V. Pugatch
CBM Collaboration
Meeting, Dubna, Oct. 13-17 2008
28
Laser test setup at KINR
V. Pugatch
CBM Collaboration
Meeting, Dubna, Oct. 13-17 2008
29
Summary. Outlook
•
Test setup (r/a sources, laser, cooling infrastructure) was designed and
built at KINR
•
Pre-Prototype Detector Module components
(supporting frames, sensors, microcables, cooling) and their connections were tested.
•
Results:
–
B1, B2 - sensors
-Unexpected performance in the interstrip gap.
-Long term instability of the leakage current
–
Supporting frames
perfect features (low mass, mechanical rigidity, thermoconductivity, easy connection and
geometry shaping etc.,)
–
Microcables (including double-layer structure)
perfect electrical and mechanical features matching CBM request.
•
Real modules assembly and their Quality Assurance
could be provided by KINR in collaboration with IMD (Kiev),
IAP (Sumy) and AEROPLAST (Kiev).
V. Pugatch
CBM Collaboration
Meeting, Dubna, Oct. 13-17 2008
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