Upload
avice-nash
View
217
Download
0
Tags:
Embed Size (px)
Citation preview
ICHEP – Beijing, China Aug 16-22, 2004 Professor Priscilla Cushman, University of Minnesota
Performance of the multi-channel Hybrid Photodiodes Performance of the multi-channel Hybrid Photodiodes for the CMS HCAL for the CMS HCAL
Professor Priscilla CushmanProfessor Priscilla CushmanUniversity of MinnesotaUniversity of Minnesota
The US-CMS HCAL Collaboration
Fermilab Florida State Purdue Notre Dame University of Illinois (Chicago) University of Mississippi University of Maryland Rochester University of Minnesota
ICHEP – Beijing, China Aug 16-22, 2004 Professor Priscilla Cushman, University of Minnesota
HCAL
The CMS Tile/Fiber Hadronic CalorimeterThe CMS Tile/Fiber Hadronic Calorimeter
HB
HE
HO
ICHEP – Beijing, China Aug 16-22, 2004 Professor Priscilla Cushman, University of Minnesota
Reading out the Towers of Tiles with WLS fiber and HPD’sReading out the Towers of Tiles with WLS fiber and HPD’s
4 Tesla Magnetic Field
ICHEP – Beijing, China Aug 16-22, 2004 Professor Priscilla Cushman, University of Minnesota
The CMS Hybrid PhotodiodeThe CMS Hybrid Photodiode
Tube Fabrication by DDelft EElectronic PProducts (Netherlands) Subcontracts: Canberra (Belgium): diodes Schott Glass (USA): fiber optic windows Kyocera (Japan): vacuum feedthru/ceramic carrier
19-channels 5.4mm each
• 12 kV across 3.3 mm gap with Vth < 4 kV => Gain of 2200
• 200 m Silicon PIN diode array, T-type, 80 V reverse bias
PIN Diode arrayCeramic feedthrough
Fiber-OpticWindow
Photocathode
e
ICHEP – Beijing, China Aug 16-22, 2004 Professor Priscilla Cushman, University of Minnesota
Larger active area: Less room for HV connection, possible field distortions
Minimize gap: Improve tube components
This has been a development projectThis has been a development project (the tube)
HV coax cable : Reliability and compatibility with RBX
RBX mountings and cookies must be rubber insulated
Gold-plated pins: Enables us to use ZIF sockets - questions of gold diffusion
FIBERS
Plate
HPD
Plate Cookie
Ring HV Cable
Electronics Interface Board
ICHEP – Beijing, China Aug 16-22, 2004 Professor Priscilla Cushman, University of Minnesota
Custom Pixel Design: 19 ch (towers) and 73 ch (short stacks)
This has been a development projectThis has been a development project ( the diode)
2 side-contacts (100 nm thick Al)
Bump-bonded vacuum feedthru
n++ contact
n++ n++p+ p+ p+ p+ p+
n+ bulk (200 m thick)
AR (16 nm sputtered Si)Metal (25 nm AL)Barrier (25 nm SiO2)
Higher pinout density: wire-bonds =>glass feedthrus => ceramic from Kyocera
Alignment to 50 m: manufacturer tolerances tightened, new measurement procedures
Improved rise time: Thinner silicon: 200 m replaces 300 m
Guard ring and drain structure: lower leakage current and better uniformity for edge pixels
Lower depletion voltage and better control of process: higher breakdown voltage
Surface aluminization and edge traces: Reduce negative crosstalk: 300 /sq => 1.7 /sq
Antireflective coating: Reduce positive crosstalk from reflected light
ICHEP – Beijing, China Aug 16-22, 2004 Professor Priscilla Cushman, University of Minnesota
300 m thick 200 m thick
Pulse width can be shortened by reducing wafer thickness d Pulse width can be shortened by reducing wafer thickness d or by increasing bias voltage, Vor by increasing bias voltage, Vbb
Drift time is approximately given by
and the shape of the plateau mirrors the internal electric field
bV V
dd
2
0lim
ICHEP – Beijing, China Aug 16-22, 2004 Professor Priscilla Cushman, University of Minnesota
Crosstalk in non-Aluminized 73-ch tube (B=1.5)
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
200 250 300 350 400
time[ns]
I/50o
hms[
mv]
pixel 36pixel 35pixel 34pixel 33pixel 37 /100
Crosstalk in Aluminized 73-ch tube (B=1.5)
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
200 250 300 350 400time[ns]
I/50o
hms[
mv]
pixel 36
pixel 35pixel 34
pixel 33pixel 37 /100
AC Crosstalk eliminated by Aluminization and edge tracesAC Crosstalk eliminated by Aluminization and edge traces
33 34 35 36 37
Pixels in center row
Positive crossstalk now observed !
ICHEP – Beijing, China Aug 16-22, 2004 Professor Priscilla Cushman, University of Minnesota
photoelectrons
Light
Re-emitted photoelectrons
APD views reflected light
pe backscatter focussed by B
Light injected thru fiber
Test Confirms Reflected Light produces optical crosstalkTest Confirms Reflected Light produces optical crosstalk
DIODE ARRAY
FIBER OPTIC & PHOTOCATHODE
ICHEP – Beijing, China Aug 16-22, 2004 Professor Priscilla Cushman, University of Minnesota
Study Problem at Minnesota, then export technology to DEPStudy Problem at Minnesota, then export technology to DEP
IMD - optical modeling package for multilayer structures
(by David L. Windt, http://cletus.phys.columbia.edu/windt/idl)Model
Data monochrometer
PIN diode
Samples: glass slides with various coatings (PECVD)
10 nm Ag120 nm SiO2
8 nm A-SiH15 nm Ag50 nm SiO2
16 nm A-SiH25 nm Al25 nm SiO2
Some OptionsMinnesota test slides
14 nm a-SiH 25 nm Al 25 nm SiO2
ICHEP – Beijing, China Aug 16-22, 2004 Professor Priscilla Cushman, University of Minnesota
Quality Assurance: Can process 40 tubes/monthQuality Assurance: Can process 40 tubes/month
fail passReturn to DEPReturn to DEP
Bake-out at 10 kV for 2 weeks
Evaluate >600 tubes, automated procedure, complete web-accessible databaseEvaluate >600 tubes, automated procedure, complete web-accessible database
Alignment measurements for 50 micron tolerance
Leakage current for each pixel and guard ring @ 80V2-D response scans (10kV, 80 V), HV gain, bias curve
crosstalk checks alignment
DC Station Machine custom ring
Single pe spectra per pixel
To FNAL for installation in readout boxes
Viking Station Lifetime: Q, Cf252, HV
High Rate and B-Field tests
subset
DC crosstalk Optical xtalk in each pixel in B-field.
AC crosstalk Recorded scope traces of AC xtalk for nn pixels
capacitance vs biasCap Station
ICHEP – Beijing, China Aug 16-22, 2004 Professor Priscilla Cushman, University of Minnesota
Samples from DC StationSamples from DC Station
Pixel Number Dark Current
1 8.6827e-0092 9.2811e-0093 2.4709e-0084 8.6967e-0095 8.995e-0096 2.2894e-0087 8.2391e-0098 2.1001e-0089 9.1783e-00910 2.2305e-008
11 1.36793e-00812 8.7693e-00913 2.0977e-00814 3.0818e-00815 1.78352e-00816 7.1035e-00917 7.2061e-00918 8.2694e-00919 7.2356e-009
Total Current 2.6605e-007
ICHEP – Beijing, China Aug 16-22, 2004 Professor Priscilla Cushman, University of Minnesota
Precision RegistrationPrecision Registration
• Test fixture = Standard Mount + metal plate with 3 alignment holes
• Scan to find centroid of alignment holes
• Same scan finds pixel intersections above and below metal piece by iterative sector equalization• Machine shop uses measured x, y, to produce Custom Ring
• Each ring is registered to its HPD via alignment pins such that Readout Module and Cookie (Notre Dame and FNAL) can be universal
Stabilized light source
HP
D
Mou
nt
Scanning Table
Integratingsphere Focussing
optics
Green filter
Metal alignment
plate
FIBERS
Plate
Alignment Pins
Plate
HPDRing HV Cable
Electronics Interface Board
ICHEP – Beijing, China Aug 16-22, 2004 Professor Priscilla Cushman, University of Minnesota
Initial Alignment Scan Final Alignment
Production #
SQ
RT(d
X2
+dY2
+dTheta
2)
0
0.05
0.1
0.15
0.2
0.25
0 50 100 150 200
Initial Alignment
Final Alignment
Alignment Procedure to 50 m is effective
50 microns
ICHEP – Beijing, China Aug 16-22, 2004 Professor Priscilla Cushman, University of Minnesota
AC Station: Viking chip serial readout at 10 MHz
HPD +interface card
AC-Coupling2 chip
128 channel PARepeater card
Laptop with ADC card
128 Mu
ltiplexer
ShaperSample& hold
10 MHzreadout
ICHEP – Beijing, China Aug 16-22, 2004 Professor Priscilla Cushman, University of Minnesota
Individual spectra for each pixel from AC StationIndividual spectra for each pixel from AC Station19-channel tube at low light levels19-channel tube at low light levels
ICHEP – Beijing, China Aug 16-22, 2004 Professor Priscilla Cushman, University of Minnesota
AZ0139031 HPD List Search Results
HPD Serial Number
Date Time QE at 480
QE at 520
QE at 560
Global Status
AZ0139031 2003-01-08 18:10:48 null null null Failed
AZ0139031 Bias Curve Search Results
HPD Serial Number
Scan Date Scan Time High Voltage Data File Bias Curve Status
AZ0139031 2001-11-15 10:35:45 739 BV(2C)AZ0139031.dat AZ0139031bvgraph.gif Passed
AZ0139031 Dark Currents Search Results
HPD Serial Number
Scan Date Scan Time
Bias Voltage
High Voltage
Summed Current
Pixel Current
Bias Current
Data File DCGraph Status
AZ0139031 2001-11-15 10:43:22 80 0 2.193e-09 2.17e-09 5.4069e-09 DCAZ0139031.dat
AZ0139031dcgraph.gif
Passed
AZ0139031 Viking Search Results
HPD Serial Number
Scan Date Scan Time Viking File Pixels Status
AZ0139031 2002-03-26 14:09:40 az0139031VIK.raw AZ0139031vikgraph.gif Passed
AZ0139031 High Voltage Curve Search Results
HPD Serial Number
Scan Date Scan Time Bias Voltage Data File Response Curve Status
AZ0139031 2001-11-15 10:44:10 80 HV(2C)AZ0139031.dat AZ0139031hvgraph.gif Passed
Database http://hcal-up.hep.umn.edu
ICHEP – Beijing, China Aug 16-22, 2004 Professor Priscilla Cushman, University of Minnesota
Tracking and Grading ProceduresTracking and Grading Procedures
Grading is done through the database Contract specifications for each test must be met.Failing one test Tube returned to DEP
http://hcal-up.hep.umn.edu/grading
Trending Plots show specification compliance vs time(see following plots for examples)
Excel spreadsheet updated and emailed to CERN financial monthlyOnly pay for the cumulative number of approved tubes
ICHEP – Beijing, China Aug 16-22, 2004 Professor Priscilla Cushman, University of Minnesota
Spec: R < 3 Ohms
Resi
stance
in O
hm
s
0
2
4
6
8
10
12
14
16
0 50 100 150 200
AC x-talk Spec: pixels/input pixel < 3%
Production #
% o
f in
put
light
0
5
10
15
20
25
30
35
40
0 50 100 150 200
Silicon resistivity and aluminized traces now under control
DEP now requires testing resistance of the aluminized traces before releasing the tubes
readout 8
and 18
Illuminate center pixel1 2 3
ICHEP – Beijing, China Aug 16-22, 2004 Professor Priscilla Cushman, University of Minnesota
DC x-talk Spec: Pixels/Input Pixel < 4%
%
of
inpu
t lig
ht
0
1
2
3
4
5
6
7
8
0 50 100 150 200
single worst pixel
All pixels
Anti-reflective coatings are reasonable
HPD
Permanent 0.3 T field isolates optical crosstalk from backscatter.
magnet
magnet
illuminated pixel
Production #
ICHEP – Beijing, China Aug 16-22, 2004 Professor Priscilla Cushman, University of Minnesota
Lifetime under HV and Light
PIN reference diodes
1.0 mm diam. WLS fibers
Blue LED’sPixel 11
HPD
Pixel 9
Lifetime Monitoring Stations monitor current (PIN diodes, HPD) and temperature
Integrated Charge: (10 CMS years = 3 C over 25.6 mm2 pixel at high
Expose to accelerated rate: Pixel 9 at 327 nA plus control pixel at CMS rate: Pixel 11 at 37 nA
Surface scans done before and after exposure distinguish between photocathode degradation and silicon damage.
ICHEP – Beijing, China Aug 16-22, 2004 Professor Priscilla Cushman, University of Minnesota
Light off
1011
9
Steady LightLight injected into 2 pixels. Run over more than 2 years
3.4 C0.4 C
13.7 C 1.6 C
19.1 C 2.2 C
Integrated Q
pixel 9 pixel 11
Pixel (led) – Pixel 10 Pixel 10
Percent change in response (gain*QE)
ICHEP – Beijing, China Aug 16-22, 2004 Professor Priscilla Cushman, University of Minnesota
Radiation Damage
Radiation Damage: (10 CMS years = 5 x 1010 n/cm2 in worst region)
Expose samples to Cf 252
1997: Oak Ridge: Early HPD version to 1013 n/cm2 Remote operation at very high flux Monitor current, characterize before and after irradiation
Result: No change in gain up to 5x1012 n/cm2, Monotonically increasing leakage current consistent with silicon
Still worked even at 10 A of leakage current!
2001, 2003: Minnesota: new HPD to >1011 n/cm2
Low flux drawer instrumented similar to Lifetime Test Light injection, in situ gain curves, reference diode
Result: Leakage current will rise at rate of 7 nA/yr in the worst location
ICHEP – Beijing, China Aug 16-22, 2004 Professor Priscilla Cushman, University of Minnesota
2004 Test Beam at CERN
HO
HB
HE
ECAL
HO
beam
beam
Wedge tests going on now
ICHEP – Beijing, China Aug 16-22, 2004 Professor Priscilla Cushman, University of Minnesota
Tracking a single channel in 4 Readout Modules
100
1000
10000
100000
0 200 400 600 800 1000 1200 1400 1600
Ch
arg
e (
fC)
RM1mean
RM2mean
RM3mean
RM4mean
CALmean
Occasional changes in LED levels
The PIN diode for HB1 flaked out for a whileThe HV was changed from 8kV to 10kV
Two Months of operation at the test beam – monitored by led
ICHEP – Beijing, China Aug 16-22, 2004 Professor Priscilla Cushman, University of Minnesota
HO Response to Muons: Select high Gain*QE tubes and run at 10 kV
Ped. RMS Peak – Ped pe S/N
Ring 0 0.95 fC 5.0 fC ~18 pe 5
Ring 1 0.91 fC 3.7 fC ~13 pe 4
Ring 2 0.92 fC 2.5 fC 9 pe <3
ICHEP – Beijing, China Aug 16-22, 2004 Professor Priscilla Cushman, University of Minnesota
Special layer-by-layer readout for the testbeam showsLongitudinal Development of a 150 GeV Pion shower in HB
HCAL alone HCAL + ECAL
layer
layer
Barrel section (HB) will be run at 8 kV for stability & lifetime
ICHEP – Beijing, China Aug 16-22, 2004 Professor Priscilla Cushman, University of Minnesota
ConclusionsConclusions
8 years ago, no existing technology could satisfy our specifications.
Development project was initiated with one Company - DEPwith backup plans which included Hamamatsu and Litton
Quality Assurance from the start can discover unanticipated problems timely feedback creates new solutions – specifications may change
Our yield under new specifications is only 60% but graded under original specs, it is closer to 80%
Photosensor fulfills all CMS HCAL requirementsas well as lifetime, stability, and operation in radiation field.
They are currently operating as expected in the Test Beam
All tubes will be manufactured and tested by February 2004.