1. For the RD42 Collaboration
Status of the R&Ds on Diamond Particle Detectors
Mara Bruzzi
University of Florence - INFN Firenze
For the RD42 Collaboration
November 6, VERTEX2002
Outline of the Talk:
Introduction
2001/2002 Milestones
Status of PolyCrystalline Diamond Particle Detectors
Single Crystal Diamond Particle Detectors
Summary and RD42 Plans
M.Bruzzi for RD42 Coll.- Status of R&D on Diamond Particle Detectors- Vertex2002, Hawaii, Nov.4-8, 2002

2. The RD42 Collaboration http://rd42.web.cern.ch/RD42/
M.Bruzzi for RD42 Coll.- Status of R&D on Diamond Particle Detectors- Vertex2002, Hawaii, Nov.4-8, 2002

3. Introduction Diamond Properties:
LHC L ~ 1034 cm-2s-1 in 10 years: f ~ 1015 n/cm2 for pixels
SLHC L ~ 1035 cm-2s-1 fast hadron f up to 1016 cm-2
 Inner tracking layers must survive
 provide high precision tracking to tag b, t, Higgs
Diamond Properties:
Radiation hardness
Low Dielectric Constant  Low Capacitance
Low Leakage Current  Low readout noise
Room Temperature Operation , Fast signal collection time
M.Bruzzi for RD42 Coll.- Status of R&D on Diamond Particle Detectors- Vertex2002, Hawaii, Nov.4-8, 2002

4. Priorities of Research in 2001/2002
2001/2002 Milestones
Priorities of Research in 2001/2002
Increase charge collection distance in a dedicated program with industry to > 250mm
Test the Tracking and radiation tolerance properties of the newest diamonds
Establish the performance of pixel detectors with radiation hard front-end chips from ATLAS and CMS
Establish the performance of large detectors
Test diamond trackers with LHC specific electronics (SCTA128 chip )
Irradiate modules sensors and front-end chips together
Finalize the geometry and metalization of diamond LHC pixel detectors
M.Bruzzi for RD42 Coll.- Status of R&D on Diamond Particle Detectors- Vertex2002, Hawaii, Nov.4-8, 2002

5. Status of PolyCrystalline Diamond Detectors
Chemical Vapour Deposition - DeBeers
Wafer diameter 5-6 inch
Metalization Cr/Au, Ti/Au, Ti/W  new
1V/mm Operation, Drift velocity saturated
Test procedure: dot  strip  pixel
M.Bruzzi for RD42 Coll.- Status of R&D on Diamond Particle Detectors- Vertex2002, Hawaii, Nov.4-8, 2002

6. R&D with DeBeers Ind. Diamond
Latest Polycrystalline Diamonds Measured with a 90Sr Source
System Gain = 124 e/mV
QMP = 60mV = 7400e
Mean Charge = 76mV = 9400e
Source data well separated from 0
Collection distance now 270mm
Most Probable Charge now 8000e
99% of PH distribution now above 3000e
FWHM/MP ~  Si has ~ 0.5
This is diamond is available in large size
The research program worked!
M.Bruzzi for RD42 Coll.- Status of R&D on Diamond Particle Detectors- Vertex2002, Hawaii, Nov.4-8, 2002

7. History of ccd progress
Now
M.Bruzzi for RD42 Coll.- Status of R&D on Diamond Particle Detectors- Vertex2002, Hawaii, Nov.4-8, 2002

8. Material Properties of PolyCrystalline Diamond
Grain-boundaries, dislocations, native defects in Polycrystalline Diamond:
limits carrier lifetime, mobility and charge collection distance
give rise to polarization and pumping effects
affect the radiation hardness ( spatial resolution improves, leakage current decrease, mean signal decreases )
Grain size: ~10-100mm
Growth side of PolyDiamond
produced by the Florence group
State-of-art DeBeers
PolyDiamond growth side after lapping
M.Bruzzi for RD42 Coll.- Status of R&D on Diamond Particle Detectors- Vertex2002, Hawaii, Nov.4-8, 2002

9. Basic Research on Defects in PolyCrystalline Diamond
Low quality
High quality
Thermally Stimulated Currents Analysis: TSC
Vrev t T
ITSC
Native defects at grain boundaries: Main + RT tail
Et ~1eV, s ~ cm2, Nt ~ cm-3
M.Bruzzi for RD42 Coll.- Status of R&D on Diamond Particle Detectors- Vertex2002, Hawaii, Nov.4-8, 2002

10. Optimising CCE through Material Removal
Columnar growth in
PolyDiamond films
Single-Crystal Line
Picture from sample
made in Florence
Removal from growth ()
and substrate ()
Higher grain-boundary density on substrate
M.Bruzzi for RD42 Coll.- Status of R&D on Diamond Particle Detectors- Vertex2002, Hawaii, Nov.4-8, 2002

11. Recent Tracking Studies - CERN Test beam setup
100 GeV/c pion/muon beam
7 planes of CVD diamond strip sensors each 2cmx2cm
50mm pitch, no intermediate strips new metalization procedure
2 additional diamond strip sensors for test
several silicon sensors for cross checks
strip electronics ( 2ms ): ENC ~100e + 14 e/pF
M.Bruzzi for RD42 Coll.- Status of R&D on Diamond Particle Detectors- Vertex2002, Hawaii, Nov.4-8, 2002

12. Results .. Work in progress Recent Tracking Studies
Uniform signals on all strips
Pedestal separated from “0” on all strips
99% of entries above 2000e
Mean signal charge ~8640e
MP signal charge ~6500e
.. Work in progress
Module with fully radiation hard SCTA128 electronics
Tested with Sr90  ready for beam test and irradiation
Charge distribution clearly separated from the noise S/N 8/1
efficiency will be measured in test beams at 40MHz clock rate
Improve position resolution by measuring charge sharing between strips
M.Bruzzi for RD42 Coll.- Status of R&D on Diamond Particle Detectors- Vertex2002, Hawaii, Nov.4-8, 2002

13. Dark Current decreases with fluence S/N decreases at 2x1015cm-2
Radiation Hardness
Signal to Noise
Resolution
Dark Current decreases with fluence
S/N decreases at 2x1015cm-2
Resolution improves at 2x1015 cm-2
M.Bruzzi for RD42 Coll.- Status of R&D on Diamond Particle Detectors- Vertex2002, Hawaii, Nov.4-8, 2002

14. Other Radiation Effects
Pumping and Trapping
f = 5x1014 n/cm2
Pumping effect less evident
Defects at Et ~1eV partially removed or compensated
f = 2.0x1015 n/cm2
M.Bruzzi for RD42 Coll.- Status of R&D on Diamond Particle Detectors- Vertex2002, Hawaii, Nov.4-8, 2002

15. Single Crystal CVD Diamond Particle Detectors
Single Crystal films produced by DeBeers: Microwave plasma-assisted CVD Homoepitaxial diamond films grown from HPHT synthetic diamond substrates.
Samples size: mm thick, 6mm diameter
Carrier RT mn ~ 4500 cm2/Vs
mh ~ 3800 cm2/Vs
~ factor 2 higher than for natural single-crystal diamond
Carrier lifetime: exceeds 2ms
Dramatic improvement as compared with natural and polycrystalline CVD diamond (~ few ns)
Dislocation less than 106 cm-2
Nitrogen content of the order of 1015cm-3
M.Bruzzi for RD42 Coll.- Status of R&D on Diamond Particle Detectors- Vertex2002, Hawaii, Nov.4-8, 2002

16. Performance of Single Crystal Diamond Detector
New metalization ( Al, no carbide involved )
M.Bruzzi for RD42 Coll.- Status of R&D on Diamond Particle Detectors- Vertex2002, Hawaii, Nov.4-8, 2002

17. Single Crystal CVD Diamond Detector: CCE
Charge Collection Distance ~ Device Thickness ( over 90-95%)
 ~ 100% Charge Collection Efficiency
M.Bruzzi for RD42 Coll.- Status of R&D on Diamond Particle Detectors- Vertex2002, Hawaii, Nov.4-8, 2002

18. Single Crystal CVD Diamond Detector: Pumping
Stable Signal, with no evidence of priming/polarization effects!
 Single Crystal Diamonds do not pump like polycrystalline material.
M.Bruzzi for RD42 Coll.- Status of R&D on Diamond Particle Detectors- Vertex2002, Hawaii, Nov.4-8, 2002

19. Polycrystalline Diamond I
Summary
Polycrystalline Diamond I
Charge collection
270mm collection distance
MP signal 8000 e
99% of charge distribution above 3000e
FWHM/MP  0.95
Tracking Results
Operated a 7 plane telescope with 50mm pitch detectors
high efficiency and tracking precision of 10-20mm
Rad-hard SCTA128 electronics (DMILL ) built
Source tests indicate high efficiency at 40MHz
Beam test and irradiation this year
Radiation Hardness
dark current decreases with fluence
some loss of S/N with fluence
Resolution improves with fluence
M.Bruzzi for RD42 Coll.- Status of R&D on Diamond Particle Detectors- Vertex2002, Hawaii, Nov.4-8, 2002

20. Polycrystalline Diamond II Single Crystal Diamond: Future ?
Summary
Polycrystalline Diamond II
Diamond Pixel Detectors
Successfully tested ATLAS and CMS pixels patterns
Bump-bonding yield  100%
Excellent correlation between telescope and pixel data
Reasonable spatial resolution attained
Radiation hard chips just arrived
Single Crystal Diamond: Future ?
Material Characteristics
mn ~ 4500 cm2/Vs , mh ~ 3800 cm2/Vs
Carrier lifetime exceeds 2ms
low native defect content
Detector performance
no pumping effect
100% charge collection efficiency over 550mm
M.Bruzzi for RD42 Coll.- Status of R&D on Diamond Particle Detectors- Vertex2002, Hawaii, Nov.4-8, 2002

21. collection distance  300mm improved uniformity
Future Plans of RD42
Charge Collection
collection distance  300mm
improved uniformity
correlation between defects and detector performance
Radiation hardness of diamond trackers and pixel detectors
Irradiation with p, p, n up to 5x1015cm-2
Beam tests with Diamond Trackers and Pixel detectors
Trackers with SCTA Electronics
Pixel detectors with ATLAS and CMS and rad hard elect.
Construct the full ATLAS diamond pixel module
M.Bruzzi for RD42 Coll.- Status of R&D on Diamond Particle Detectors- Vertex2002, Hawaii, Nov.4-8, 2002