S 2 DEL - Solid State and Diamond Electronics Lab SOLARIS PHOTONICS ROMA TRE 1/20 Radiation Hard Imaging Detectors based on Diamond Electronics Marco Girolami 1, Arnaldo Galbiati 2, Stefano Salvatori 3 1 Department of Physics, Roma TRE University, Rome, Italy 2 Solaris Photonics, London, United Kingdom 3 Department of Electronic Engineering, Roma TRE University, Rome, Italy

S 2 DEL - Solid State and Diamond Electronics Lab SOLARIS PHOTONICS ROMA TRE 2/20 Radiation Hard Imaging Detectors based on Diamond Electronics INTRODUCTION This work reports on the realization and test of a compact diamond-based radiation beam profiling system: multistrip and pixel structures have been used for the realization of 1D and 2D position and imaging detectors, respectively. A dedicated read-out electronic circuitry has been designed and used to independently sample the signal produced by each strip (or pixel), enabling a real-time beam profile reconstruction.

S 2 DEL - Solid State and Diamond Electronics Lab SOLARIS PHOTONICS ROMA TRE 3/20 Radiation Hard Imaging Detectors based on Diamond Electronics WHY ? can be operated at room temperature and are able to detect deep UV photons, X-rays, gamma rays, charged particles, M.I.P. and neutrons for a wide range of industrial and research applications as: particle tracking at CERN, beam conditions monitoring for synchrotrons and LINACS, radiotheraphy imaging, excimer laser beam diagnostic etc.

S 2 DEL - Solid State and Diamond Electronics Lab SOLARIS PHOTONICS ROMA TRE 4/20 WHY ? M. Pillon et al., Nuclear Instruments and Methods in Physics Research A 640 (2011) 185–191 Alpha Spectrum with Diamond Radiation Detectors

S 2 DEL - Solid State and Diamond Electronics Lab SOLARIS PHOTONICS ROMA TRE 5/20 AMPTEK Cool-X source, double emission: Cu K α = 8.05 keV Ta L α = 8.14 keV Energy resolution : 730 : 900 eV X-ray spectroscopy G.Conte, M.Girolami, S.Salvatori, V.Ralchenko “X- ray diamond detectors with energy resolution” Applied Physics Letters 91, (2007)

S 2 DEL - Solid State and Diamond Electronics Lab SOLARIS PHOTONICS ROMA TRE 6/20 UV and X-ray source imaging Focus: Real-time monitoring of beam shape and intensity Microanalisys techniques (EXMA, XPS, XRD, XRF) Industrial radiography Medical diagnostics and radiotherapy VLSI-ULSI integrated circuits and MEMS lithography Refractive eye surgery (LASIK) Reflected UV imaging UV X-rays

S 2 DEL - Solid State and Diamond Electronics Lab SOLARIS PHOTONICS ROMA TRE 7/20 State-of-the art silicon beam profilers CCD beam profilers for UV and X-ray source imaging: PROs: well-established technology good Q.E. for back-thinned devices large area detectors CONs: radiation damage strong VIS-IR absorption large dimensions, high cost It’s mandatory the use of: attenuators (to limit radiation damage) complex optical systems to improve UV-VIS discrimination Scheme of a commercial UV beam profiler

S 2 DEL - Solid State and Diamond Electronics Lab SOLARIS PHOTONICS ROMA TRE 8/20 Why diamond? The special characteristics of diamond allow its use in extreme environmental conditions like high temperature, high radiation, and highly corrosive environments. high carrier mobility (e.g. greater than silicon)-> ultra fast high radiation hardness-> High S/N ratio after radiation damage (e.g.: see oral N7-4) → no frequent replacements Resistivity ~5 orders of magnitude > Silicon high break down field transparency in the VIS-IR spectral regions wide bandgap (5.45 eV)-> Low leakage current highest thermal conductivity (22 Wcm -1 K -1 )-> no cooling No need for attenuators and/or converters between source and DUT

S 2 DEL - Solid State and Diamond Electronics Lab SOLARIS PHOTONICS ROMA TRE 9/20 Dark current and spectral photoconductivity Sandwich configuration (Ag) Ohmic behavior up to 100 V bias Low dark current (few pA) UV light: λ = 220 nm, P INC ≈ 1 μ W High quality sample High UV vs. VIS selectivity Low sub-bandgap conductivity Low surface recombination

S 2 DEL - Solid State and Diamond Electronics Lab SOLARIS PHOTONICS ROMA TRE 10/20 Response speed and linearity Single laser pulses (ArF, 193 nm) Rise-time ~ 1.3 ns (VT) Fall-time ~ 6 ns Intensity-dependent pulse shape Linearity up to a 5×10 -3 mJ /cm 2 (trap- assisted recombination) Band-to-band recombination prevails at higher energies (sub-linearity)

S 2 DEL - Solid State and Diamond Electronics Lab SOLARIS PHOTONICS ROMA TRE 11/20 1D and 2D pixel detectors technology multistrip structure 32 strips (6 mm × 80 μ m) Ag contacts wire-bonding 1D detector multipixel structure 36 pixel (750 × 750 μ m 2 ) Ag contacts wire-bonding 2D detector

S 2 DEL - Solid State and Diamond Electronics Lab SOLARIS PHOTONICS ROMA TRE 12/20 Operation principle

S 2 DEL - Solid State and Diamond Electronics Lab SOLARIS PHOTONICS ROMA TRE 13/20 Multichannel electronic system (32/64 channels) Integration time: 50 μ s ÷ 1s Selectable charge range: 50 pC ÷ 350 pC Sensitivity: LSB < 15 fC (150 pC FS) ADC resolution: 20 bit Floating input ADC resolution: 14 bit Selectable number of acquisitions: 1 ÷ 2 10 Max. data throughput: 2 kHz (2∙64 kSPS) Math tools: centroid, mean value, displacement Main features

S 2 DEL - Solid State and Diamond Electronics Lab SOLARIS PHOTONICS ROMA TRE 14/20 UV position-sensitive detectors Centroid vs. displacement linearity Spatial resolution: 5 μ m (1D), 20 μ m (2D)

S 2 DEL - Solid State and Diamond Electronics Lab SOLARIS PHOTONICS ROMA TRE 15/20 UV 1D beam profiling (32 channels) Example of a 8-channels acquisition in a color-graded scale 32 channels beam profile acquired along horizontal axis Monochromatic UV source: spot 5 x 5 mm 2 λ = 220 nm P INC ≈ 1 μ W Sensor held on a micrometric moving stage (10 μ m of resolution) It’s worth noting the relative low standard deviation values of the ADC output codes we gained M.Girolami, P.Allegrini, G.Conte and S.Salvatori – “CVD Diamond Detectors for Real-Time Beam Profile Measurements” – Proceedings of The 7th IEEE Conference on Sensors, pp (2008)

S 2 DEL - Solid State and Diamond Electronics Lab SOLARIS PHOTONICS ROMA TRE 16/20 2D detector for UV and X-ray source imaging

S 2 DEL - Solid State and Diamond Electronics Lab SOLARIS PHOTONICS ROMA TRE 17/20 Excimer laser pulse beam profile: ArF 193 nm Closed shutter Single pulse “Ghost peak” Single excimer laser pulses real-time monitoring

S 2 DEL - Solid State and Diamond Electronics Lab SOLARIS PHOTONICS ROMA TRE 18/ mm Centroide: ( 1.29, 3.66 ) 5.50 mm Centroide: ( 1.36, 3.67 ) 5.75 mm Centroide: ( 1.49, 3.69 ) 6.00 mm Centroide: ( 1.69, 3.68 ) 6.25 mm Centroide: ( 2.02, 3.76 ) 6.50 mm Centroide: ( 2.40, 3.72 ) 6.75 mm Centroide: ( 2.82, 3.78 ) 7.00 mm Centroide: ( 3.25, 3.74 ) 7.25 mm Centroide: ( 3.66, 3.78 ) 7.50 mm Centroide: ( 4.11, 3.78 ) 7.75 mm Centroide: ( 4.49, 3.78 ) 8.00 mm Centroide: ( 4.94, 3.77 ) 8.50 mm Centroide: ( 5.57, 3.60 ) 8.75 mm Centroide: ( 5.71, 3.59 ) 9.00 mm Centroide: ( 5.70, 3.56 ) 8.25 mm Centroide: ( 5.33, 3.70 ) buio Centroide: ( 3.51, 3.54 ) Pixel position Temporal evolution of UV deuterium lamp radiation Deuterium 10 μ W, 220 nm

S 2 DEL - Solid State and Diamond Electronics Lab SOLARIS PHOTONICS ROMA TRE 19/20 X-ray beam profiles Coolidge tube: Mo target (K α = keV, K β =19.6 keV) V = 45 kV I = 1.1 mA spot-size 3 mm Displacement along X-axis

S 2 DEL - Solid State and Diamond Electronics Lab SOLARIS PHOTONICS ROMA TRE 20/20 X-ray beam profiles Displacement along Z-axis X-ray beam divergence increases with source- detector distance

S 2 DEL - Solid State and Diamond Electronics Lab SOLARIS PHOTONICS ROMA TRE 21/20 Conclusions Diamond multistrip and pixel structures have been used for the realization of radiation hard imaging detectors with dedicated read-out electronics for real-time photon and particle beam profile reconstruction. Integration time: 50 μs ÷ 1s Spatial resolution: 5 μm (1D), 20 μm (2D)

S 2 DEL - Solid State and Diamond Electronics Lab SOLARIS PHOTONICS ROMA TRE 22/20 Future Work Diamond radiation hard imaging detectors with dedicated fast electronics: 1.6 GHz Amplifier+5 GS/s Digitizers APPLICATIONS: Time of flight Pulse shape analysis Spectroscopy/Pixel THANK YOU FOR YOUR ATTENTION !