1. (proxy for Harris Kagan) for the RD42 Collaboration
RD42 Results and Status
Marko Mikuž
(proxy for Harris Kagan)
Ohio State University
for the RD42 Collaboration
Vertex 2017
September 10-15, 2017
Outline of Talk
Introduction – Motivation, RD42
Radiation Tolerance
Diamond Devices in the LHC and Experiments
Rate Studies
Diamond Device Development – 3D Diamond
Diamond Device Development – BCM’
Summary

2. Introduction - Motivation
Present Situation:
Innermost layers  highest radiation damage (~100 MHz/cm2)
Current detectors designed to survive ~12 months in HL- LHC
 R&D for more radiation tolerant detector designs and/or materials
Diamond as a Detector Material:
Properties:
radiation tolerance
insulating material
high charge carrier mobility
Smaller signal than in same thickness of silicon
RD42 work:
Investigation of signals in various detector designs:
pad  full diamond as a single cell readout
pixel  diamond sensor on pixel chips
3D  strip/pixel detector with design to reduce drift distance
Vertex 2017 – Asturias, Spain
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3. Introduction - The 2017 RD42 Collaboration
130 participants
32 institutes
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4. Diamond as a Particle Detector
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5. Radiation Tolerance
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6. Radiation Tolerance Test Beam Setup
characterization of irradiated devices in beam tests
transparent or unbiased hit prediction from telescope
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7. Radiation Tolerance – Analysis Strategy
Measure signal response as a function of predicted position
Direct measurement of charge collection distance (CCD)
CCD = average distance e-h pairs drift apart under E-field
Convert CCD to mean free path (MFP) - assume ~same MFP for e,h
Damage equation:
Fit in 1/l (=1/mfp) vs f space
n number of traps
n0 initial traps in material
k damage constant
fluence
l MFP
l0 initial MFP
n = n0 + kf
↓ ↓
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8. Radiation Tolerance Example – 800 MeV protons
Plot single-crystal and poly on
same graph
Fit in 1/l space
Damage constant (=slope) for single-crystal and poly the same
Do the same for all energies,
species
Lukas Bäni, PhD Thesis, ETH Zürich, 2017
Vertex 2017 – Asturias, Spain
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9. Radiation Tolerance Lukas Bäni, PhD Thesis ETH Zürich, 2017
Lukas Bäni, PhD Thesis
ETH Zürich, 2017
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10. Radiation Tolerance
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11. Applications in the LHC and Experiments
- beam condition/beam loss monitors
- pixel detectors
- 3D devices
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12. Diamond devices in experiments
Beam Conditions Monitors/Beam Loss Monitors
Essentially all modern collider experiments
Current generation Pixel Detectors
ATLAS Diamond Beam Monitor (DBM)
Future HL-LHC Trackers
3D diamond
Future BCM’
Multipad design
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13. Rate Studies
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14. Rate studies in pCVD diamond
Done at PSI - 2 yrs ago published rates up to 300kHz/cm2
Last year w/new electronics, rates up to 10-20MHz/cm2
Pad detector tested in ETH-Z telescope (CMS Pixels)
Electronics is prototype for HL-LHC BCM/BLM
19.8ns bunch spacing clearly visible
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15. Rate studies in pCVD diamond
Last year w/new electronics, rates up to 10MHz/cm2
No rate dependence observed in pCVD up to 10-15MHz/cm2
No absolute pulse height and noise calibration yet
Now extending dose to 1016 n/cm2
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16. Device Development – 3D Diamond
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17. 3D device in pCVD diamond
after large irradiation  all detector materials trap limited (mfp < 75 μm)
keep drift distances smaller than mean free path
bias and readout electrode inside detector material
same thickness Δ  same generated charge  shorter drift distance L
electrode columns drilled with 800 nm femtosecond laser
convert diamond into conductive mixture of carbon phases (~kΩ)
Vertex 2017 – Asturias, Spain
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18. 3D multi-device in pCVD diamond
pCVD diamond with 3D, phantom and strip detector on single sensor
3D column drilling & connection efficiency 92%
3D cell size 150μm x 150μm
signal read out as ganged cells
missing columns
good columns
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19. 3D multi-device in pCVD diamond
Square cells visible
9/99 broken readout, 15/120 field columns
Signals readout as ganged cells (strips)
Signal in 3D bigger (already by eye) than in planar
Phantom (no columns)  no pulse height
Planar Strip
Phantom 3D
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20. 3D multi-device in pCVD diamond
Measured signal (diamond thickness 525 μm):
Planar Strip ave charge (Vbias = 1000 V)
6,900e or ccd=192um
3D ave charge (Vbias = 60 V)
13,500e or ccdeq= um
For the first time collect ~75% of charge in pCVD
Vertex 2017 – Asturias, Spain
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21. Full 3D device in pCVD diamond
Tested first full 3D device in pCVD (May/Sept 2016) with three dramatic improvements
An order of magnitude more cells (1188 vs 99)
Smaller cell size (100μm vs 150μm), hole diameter (2 vs 5 μm)
Higher column production efficiency (99% vs 92%)
Readout side
HV bias side
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22. Full 3D device in pCVD diamond
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23. 3D Diamond Pixels
First 3D pixel device in pCVD (2017) [100μm x 150μm cells]
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24. 3D Diamond Pixels
First 3D pixel device in pCVD – use CMS pixel readout chip
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25. 3D Diamond Pixels – Preliminary Results
98.5% efficiency
Planar Silicon Pixel (ref)
99.3% efficiency
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26. 3D Diamond Pixel – New Design
Produced a 3500cell pixel prototype w/50μm x 50μm pitch
Two being produced:
Oxford (complete)
Manchester (in progress)
Can do metallization to fit
any known pixel chip
Bump bonding
Took data in August test
beam at PSI
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27. 3D Diamond Pixel – New Design
Preliminary Results (50μmx50μm pixels)
Readout with CMS pixel readout
6 columns (3x2) ganged together
Preliminary efficiency 99.2%
Collect >90% of charge!
Vertex 2017 – Asturias, Spain
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28. Lots of progress in diamond with HL-LHC in view
Summary
Lots of progress in diamond with HL-LHC in view
ATLAS/CMS -BCM, BLM, DBM all working in LHC
Abort, luminosity and background functionality in all LHC expts
Quantified understanding of rate effects in diamond
pCVD shows no rate effect up to V
3D detector prototypes made great progress
3D works in pCVD diamond; scale up worked; smaller cells worked
3D diamond pixel devices being produced
All work as expected
Visible improvements in each step
Efficiencies look good; PH in progress
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29. Backup Slides
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30. Device Development – BCM’
- abort threshold
- danger level, safety margin
- luminosity
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31. Diamond development – BCM’
Abort and Luminosity Functions
Abort
Require out-of-time and in-time signals above
threshold signifying beam background at the danger
Level
Danger levels can be very high
ATLAS SCT 25k/cm2/BC i.e. ~4000x lumi signal
Need to keep flexibility for threshold settings
Luminosity
Main algorithm: (absence of) in-time hits
Max sensitivity ~1.6 hits/cell
Need robust device, signal stability paramount
Vertex 2017 – Asturias, Spain
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32. Diamond development – BCM’
Present BCM suffers from abort-lumi incompatibility
Abort thresholds can not be set higher without
abandoning lumi
Fast timing needed for abort lowers S/N thus limiting
lumi stability
Separate functions at the HL-LHC
Two fast devices from sensor to off-detector
Keep as much commonality as possible
4 stations/side with abort, lumi-BCM’, BLM
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33. Diamond development – BCM’
Sensor Design
last week with RD42 fast amp used for Rate Studies!
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34. Diamond development – BCM’
Start with RD42 fast amp used in rate studies
Designed in 130nm; will be updated to 65nm
Rise time 3-6ns; Baseline recovery time 12-18ns
Noise for 2pf input ~550e
ATLAS electronics ideas
Two preamp designs since otherwise large dynamic
range (104) needed to cover lumi and abort in same
channel
High gain for lumi; low gain for abort. Optimize gain
and speed vs SNR for lumi and abort separately
Rise time ~few ns; return to baseline 10ns
Tune parameters based on beam tests
16 channels (8/8 lumi/abort)
Vertex 2017 – Asturias, Spain
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35. Diamond development – BCM’
Prototype test with 9.2
Bunches 19.8ns apart clearly separated
Trigger is at 69ns
Hits in bunch before trigger not allowed
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