| 1. |
- Bertuccio, Giuseppe, et al.
(author)
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Advances in silicon carbide X-ray detectors
- 2011
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In: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier. - 0168-9002 .- 1872-9576. ; 652:1, s. 193-196
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Journal article (peer-reviewed)abstract
- The latest advances in SiC X-ray detectors are presented: a pixel detector coupled to a custom ultra-low noise CMOS preamplifier has been characterized at room and high temperature. An equivalent noise energy (ENE) of 113 eV FWHM, corresponding to 6.1 electrons r.m.s., has been achieved with the detector/front- end system operating at 30 °C. A Fano factor of F = 0.10 has been estimated from the 55Fe spectrum. When the system is heated up to 100 °C, the measured ENE is 163 eV FWHM (8.9 electrons r.m.s.). It is determined that both at room and at high temperature the performance are fully limited by the noise of the front-end electronics. It is also presented the capability of SiC detectors to operate in environments under unstable temperature conditions without any apparatus for temperature stabilization; it has been proved that a SiC detector can acquire high resolution X-ray spectra without spectral line degradation while the system temperature changes between 30 °C and 75 °C.
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| 2. |
- Bertuccio, Giuseppe, et al.
(author)
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Silicon carbide detector for laser-generated plasma radiation
- 2013
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In: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 272, s. 128-131
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Journal article (peer-reviewed)abstract
- We present the performance of a Silicon Carbide (SiC) detector in the acquisition of the radiation emittedby laser generated plasmas. The detector has been employed in time of flight (TOF) configuration withinan experiment performed at the Prague Asterix Laser System (PALS). The detector is a 5 mm2 area 100 nmthick circular Ni SiC Schottky junction on a high purity 4H-SiC epitaxial layer 115 μm thick. Currentsignals from the detector with amplitudes up to 1.6 A have been measured, achieving voltage signals over 80 V on a 50 Ω load resistance with excellent signal to noise ratios. Resolution of few nanoseconds hasbeen experimentally demonstrated in TOF measurements. The detector has operated at 250 V DC biasunder extreme operating conditions with no observable performance degradation.
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| 3. |
- Bertuccio, Giuseppe, et al.
(author)
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Silicon Carbide Detectors for in vivo Dosimetry
- 2014
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In: IEEE Transactions on Nuclear Science. - : IEEE. - 0018-9499 .- 1558-1578. ; 61:2, s. 961-966
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Journal article (peer-reviewed)abstract
- Semiconductor detectors for in vivo dosimetry haveserved in recent years as an important part of quality assurancefor radiotherapy. Silicon carbide (SiC) can represent a bettersemiconductor with respect to the more popular silicon (Si) thanksto its physical characteristics such as wide bandgap, high electronsaturation velocity, lower effective atomic number, and high radiationresistance to X and gamma rays. In this article we present aninvestigation aimed at characterizing 4H-SiC epitaxial Schottkydiodes as in vivo dosimeters. The electrical characterization atroom temperature showed ultra low leakage current densities aslow as 0.1 pA/cm at 100 V bias with negligible dependence ontemperature. The SiC diode was tested as radiotherapy dosimeterusing 6 MV photon beams from a linear accelerator in a typicalclinical setting. Collected charge as a function of exposed radiationdose were measured and compared to three standard commerciallyavailable silicon dosimeters. A sensitivity of 23 nC/Gy withlinearity errors within 0.5% and time stability of 0.6% wereachieved. No negligible effects on the diode I-V characteristicsafter irradiation were observed.
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| 4. |
- Bertuccio, Giuseppe, et al.
(author)
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Silicon Carbide X-Ray Detectors Operating at Room and High Temperature
- 2014
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Conference paper (peer-reviewed)abstract
- Silicon Carbide (SiC) is a wide bandgap semiconductor with attractive physical properties for manufacturing X-ray detectors [1]. The density of SiC crystal allow an X‑ray absorption similar to Silicon. The wide bandgap of SiC (3.2 eV) allows to make high Schottky barriers and minimises the reverse current from thermal generation of charge carriers. The SiC breakdown field (2 MV/cm) and the high saturation velocities of the charge carriers (200 mm/ns) make the detector response very fast and not affected by charge trapping degradation.In this talk, we present the SiC X-ray detectors we have developed. The detectors show leakage current densities as low as J=0.1 pA/cm2 at +25°C, three orders of magnitude lower than those of the best silicon detectors and make SiC detectors practically noiseless at room temperature. The detectors have been tested also at high temperatures: at T=+100°C the J= 1 nA/cm2, allowing excellent X-ray spectrometry even at such high temperatures, forbidden to conventional semiconductor detectors. In addition we will show that our SiC detectors can also operate while the temperature is freely changing of tens of °C, without affecting spectra quality.The possibility to make the detector operating without any cooling system even at high temperature with adequate energy resolution can open new perspectives in X‑ray spectrometry applications, even ever considered before.
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| 5. |
- Bertuccio, Giuseppe, et al.
(author)
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X-γ Ray Spectroscopy With Semi-Insulating 4H-Silicon Carbide
- 2013
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In: IEEE Transactions on Nuclear Science. - : IEEE. - 0018-9499 .- 1558-1578. ; 60:2, s. 1436-1441
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Journal article (peer-reviewed)abstract
- Radiation detectors on a semi-insulating (SI) 4H siliconcarbide (SiC) wafer have been manufactured and characterizedwith X and photons in the range 8–59 keV. The detectors were 400 μm diameter circular Ni-SiC junctions on an SI 4H-SiC wafer thinned to 70 μm. Dark current densities of 3.5 nA/cm2 at 20 °C and 0.3 μA/cm2 at 104 °C with an internal electric field of 7 kV/cm have been measured. X-γ ray spectra from 241Am have been acquired at room temperature with pulser line width of 756 eV FWHM. The charge collection efficiency (CCE) has been measured under different experimental conditions with a maximum CCE = 75 % at room temperature. Polarization effects have been observed, and the dependence of CCE on time and temperature has been measured and analyzed. The charge trapping has been described by the Hecht model with a maximum totalmean drift length of 107 μm at room temperature.
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| 6. |
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Experimental test of TOF diagnostics for PW class lasers
- 2013
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Editorial proceedings (peer-reviewed)abstract
- New particle acceleration regimes driven by PW class lasers imply the development of new in-situ diagnostics. Before constructing new types of detectors one must test currently available diagnostics in these new regimes ofhigh intensity laser-matter interaction. Experimental tests on two types of time of flight detectors are presented, demonstrating the possibility of their measuring capabilities in harsh conditions, namely the strong laser induced electromagnetic pulse. A recently developed silicon carbide detector was successfully tested and particle beams were characterized. Further tests were performed on a detector based on secondary emission of electrons during the transition of laser accelerated particle beams. The presented results show a clear consistency and sufficient capabilities for high intensity laser driven particle beam detection.
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| 7. |
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Silicon Carbide Microstrip Detectors for High Resolution X-Ray Spectroscopy
- 2012
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Editorial proceedings (peer-reviewed)abstract
- Silicon Carbide (SiC) is a wide bandgap semiconductor with outstanding physical properties for realizing ionizing radiation detectors. We present the manufacturing, electrical and spectroscopic characterization of a prototype SiC microstrip detector constituted by 32 strips, 2 mm long, 25 μm wide with 55 μm pitch. The detectors have been fabricated on 115 μm thick undoped epitaxial 4H-SiC using Ni-SiC Schottky junctions. The measured leakage currents are below 5 fA at 25 °C and 0.6 pA at 107 °C with internal electric fields up to 30 kV/cm. X-ray spectra from 55Fe and 241Am with energy resolution of 224 eV FWHM and 249 eV FWHM (12-13.5 electrons r.m.s.) have been acquired at 20 °C and 80 °C, respectively.
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| 8. |
- Torrisi, Lorenzo, et al.
(author)
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High intensity laser-generating plasmas in forward direction in thin films and Thomson parabola spectrometer monitorage
- 2010
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Reports (other academic/artistic)abstract
- Asterix laser at PALS Laboratory of Prague, operating at 1315 nm fundamental wavelength, 300 ps pulse duration, 1016 W/cm2 intensity and single pulse mode, was employed to irradiate thin hydrogenated targets placed in high vacuum. Non-equilibrium plasmas were obtained in forward direction, i.e. along the normal to the target surface on the rear of the irradiated thin films. Plasmas were monitored with different ion detectors, placed around the direction normal to the target. The main detector was a Thomson parabola spectrometer aligned along the normal in forward direction. This spectrometer permits to provide many plasma parameters concerning the involved ions (energy, charge state, mass,...) obtained in a single laser shot. The spectrometer images, obtained by using a MCP coupled to a fast CCD camera, can be processed by a comparison with the simulation data obtained by a proper software. High ion energies and charge states have been obtained as a function of the laser parameters, target thickness and composition and irradiation conditions.
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| 9. |
- Torrisi, Lorenzo, et al.
(author)
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Proton driven acceleration by intense laser pulses irradiating thin hydrogenated targets
- 2013
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In: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 272, s. 2-5
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Journal article (peer-reviewed)abstract
- The Asterix iodine laser of the PALS laboratory in Prague, operating at 1315 nm fundamental frequency, 300 ps pulse duration, 600 J maximum pulse energy and 1016 W/cm2 intensity, is employed to irradiatethin hydrogenated targets placed in high vacuum. Different metallic and polymeric targets allow togenerate multi-energetic and multi-specie ion beams showing peculiar properties. The plasma obtainedby the laser irradiation is monitored, in terms of properties of the emitted charge particles, by using time-of-flight techniques and Thomson parabola spectrometer (TPS). A particular attention is given tothe proton beam production in terms of the maximum energy, emission yield and angular distributionas a function of the laser energy, focal position (FP), target thickness and composition.
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| 10. |
- Zhang, Xiaodong, et al.
(author)
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Characterizing the Timing Performance of a Fast 4H-SiC Detector With an 241Am Source
- 2013
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In: IEEE Transactions on Nuclear Science. - : IEEE. - 0018-9499 .- 1558-1578. ; 60:3, s. 2352-2356
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Journal article (peer-reviewed)abstract
- An SPX4 4H-silicon carbide detector consisting of 4 x 4 pixels was developed and studied experimentally. Its pixel size is 400 μm x 400 μm . A timing resolution of 117 11 ps fullwidth at half-maximum (FWHM) has been measured for thedetection of alphas. With such good timing performance andhigh granularity, the SiC pixel detector holds great promise as anassociated alpha-particle detector for fast neutron imaging.
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