| 1. |
- Bertuccio, Giuseppe, et al.
(författare)
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Advances in silicon carbide X-ray detectors
- 2011
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier. - 0168-9002 .- 1872-9576. ; 652:1, s. 193-196
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Tidskriftsartikel (refereegranskat)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.
(författare)
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Silicon carbide detector for laser-generated plasma radiation
- 2013
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Ingår i: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 272, s. 128-131
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Tidskriftsartikel (refereegranskat)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.
(författare)
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Silicon Carbide Detectors for in vivo Dosimetry
- 2014
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Ingår i: IEEE Transactions on Nuclear Science. - : IEEE. - 0018-9499 .- 1558-1578. ; 61:2, s. 961-966
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Tidskriftsartikel (refereegranskat)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.
(författare)
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Silicon Carbide X-Ray Detectors Operating at Room and High Temperature
- 2014
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Konferensbidrag (refereegranskat)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.
(författare)
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Ultra Low Noise Epitaxial 4H-SiC X-Ray Detectors
- 2009
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Ingår i: Materials Science Forum. - : Trans Tech Publications Inc.. - 0255-5476 .- 1662-9752. ; 615-617, s. 845-848
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Tidskriftsartikel (refereegranskat)abstract
- The design and the experimental results of some prototypes of SiC X-ray detectors are presented. The devices have been manufactured on top of 2 inch 4H-SiC wafer with 115 μm thick undoped high purity epitaxial layer, which constitutes the detection’s active volume. Pad and pixel detectors based on Ni-Schottky junctions have been tested. The residual doping of the epi-layer was found tobe extremely low, 3.7 x 1013 cm-3, allowing to achieve the highest detection efficiency and the lower specific capacitance of the detectors. At 22 °C and in operating bias condition, the reverse current densities of the detector’s Schottky junctions have been measured to be between J = 0.3 pA/cm2 and J = 4 pA/cm2; these values are more than two orders of magnitude lower than those of state of the art silicon detectors. With such low leakage currents, the equivalent electronic noise of SiC pixel detectors is as low as 0.5 electrons r.m.s at room temperature, which represents a new state of the art in the scenario of semiconductor radiation detectors.
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| 6. |
- Bertuccio, Giuseppe, et al.
(författare)
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X-γ Ray Spectroscopy With Semi-Insulating 4H-Silicon Carbide
- 2013
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Ingår i: IEEE Transactions on Nuclear Science. - : IEEE. - 0018-9499 .- 1558-1578. ; 60:2, s. 1436-1441
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Tidskriftsartikel (refereegranskat)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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| 7. |
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Experimental test of TOF diagnostics for PW class lasers
- 2013
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Proceedings (redaktörskap) (refereegranskat)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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| 8. |
- Picetti, Edoardo, et al.
(författare)
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Early management of adult traumatic spinal cord injury in patients with polytrauma : a consensus and clinical recommendations jointly developed by the World Society of Emergency Surgery (WSES) & the European Association of Neurosurgical Societies (EANS)
- 2024
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Ingår i: World Journal of Emergency Surgery. - : BioMed Central (BMC). - 1749-7922. ; 19
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Tidskriftsartikel (refereegranskat)abstract
- Background: The early management of polytrauma patients with traumatic spinal cord injury (tSCI) is a major challenge. Sparse data is available to provide optimal care in this scenario and worldwide variability in clinical practice has been documented in recent studies.Methods: A multidisciplinary consensus panel of physicians selected for their established clinical and scientific expertise in the acute management of tSCI polytrauma patients with different specializations was established. The World Society of Emergency Surgery (WSES) and the European Association of Neurosurgical Societies (EANS) endorsed the consensus, and a modified Delphi approach was adopted.Results: A total of 17 statements were proposed and discussed. A consensus was reached generating 17 recommendations (16 strong and 1 weak).Conclusions: This consensus provides practical recommendations to support a clinician's decision making in the management of tSCI polytrauma patients.
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| 9. |
- Picetti, Edoardo, et al.
(författare)
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Early management of isolated severe traumatic brain injury patients in a hospital without neurosurgical capabilities : a consensus and clinical recommendations of the World Society of Emergency Surgery (WSES)
- 2023
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Ingår i: World Journal of Emergency Surgery. - : BioMed Central (BMC). - 1749-7922. ; 18:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Severe traumatic brain-injured (TBI) patients should be primarily admitted to a hub trauma center (hospital with neurosurgical capabilities) to allow immediate delivery of appropriate care in a specialized environment. Sometimes, severe TBI patients are admitted to a spoke hospital (hospital without neurosurgical capabilities), and scarce data are available regarding the optimal management of severe isolated TBI patients who do not have immediate access to neurosurgical care.METHODS: A multidisciplinary consensus panel composed of 41 physicians selected for their established clinical and scientific expertise in the acute management of TBI patients with different specializations (anesthesia/intensive care, neurocritical care, acute care surgery, neurosurgery and neuroradiology) was established. The consensus was endorsed by the World Society of Emergency Surgery, and a modified Delphi approach was adopted.RESULTS: A total of 28 statements were proposed and discussed. Consensus was reached on 22 strong recommendations and 3 weak recommendations. In three cases, where consensus was not reached, no recommendation was provided.CONCLUSIONS: This consensus provides practical recommendations to support clinician's decision making in the management of isolated severe TBI patients in centers without neurosurgical capabilities and during transfer to a hub center.
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| 10. |
- Puglisi, Donatella, et al.
(författare)
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Diffusion Length in n-doped 4H Silicon Carbide Crystals Detected by Alpha Particle Probe
- 2009
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Ingår i: Materials Science Forum. - : Trans Tech Publications Inc.. - 0255-5476 .- 1662-9752. ; 615-617, s. 857-860
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Tidskriftsartikel (refereegranskat)abstract
- The achievement of nuclear detectors in silicon carbide imposes severe constraints onthe electronic quality and thickness of the material due to the relatively high value of the energyrequired to generate an electron-hole pair (7.8 eV) in this material compared to the value for Si (3.6 eV). In this work, 4H-SiC charged particle detectors were realised using epitaxial layers ofn-type doping as active region. The thickness of the epilayer is always below 80 μm with a netdoping concentration in the range of 8 x 1013 to 1016 cm-3. These properties allowed the fabricationof Schottky diodes that operate well as radiation detectors. At low doping concentration, theepilayer is totally depleted at quite low reverse bias (≈ 50 V), thereby obtaining the maximumactive volume.
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| 11. |
- Puglisi, Donatella, 1980-, et al.
(författare)
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Silicon Carbide Microstrip Radiation Detectors
- 2019
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Ingår i: Micromachines. - : MDPI. - 2072-666X. ; 10:12
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Tidskriftsartikel (refereegranskat)abstract
- Compared with the most commonly used silicon and germanium, which need to work at cryogenic or low temperatures to decrease their noise levels, wide-bandgap compound semiconductors such as silicon carbide allow the operation of radiation detectors at room temperature, with high performance, and without the use of any bulky and expensive cooling equipment. In this work, we investigated the electrical and spectroscopic performance of an innovative position-sensitive semiconductor radiation detector in epitaxial 4H-SiC. The full depletion of the epitaxial layer (124 µm, 5.2 × 1013 cm−3) was reached by biasing the detector up to 600 V. For comparison, two different microstrip detectors were fully characterized from −20 °C to +107 °C. The obtained results show that our prototype detector is suitable for high resolution X-ray spectroscopy with imaging capability in a wide range of operating temperatures.
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| 12. |
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Silicon Carbide Microstrip Detectors for High Resolution X-Ray Spectroscopy
- 2012
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Proceedings (redaktörskap) (refereegranskat)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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| 13. |
- Torrisi, Lorenzo, et al.
(författare)
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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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Rapport (övrigt vetenskapligt/konstnärligt)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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| 14. |
- Torrisi, Lorenzo, et al.
(författare)
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Proton driven acceleration by intense laser pulses irradiating thin hydrogenated targets
- 2013
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Ingår i: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 272, s. 2-5
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Tidskriftsartikel (refereegranskat)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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| 15. |
- Zhang, Xiaodong, et al.
(författare)
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Characterizing the Timing Performance of a Fast 4H-SiC Detector With an 241Am Source
- 2013
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Ingår i: IEEE Transactions on Nuclear Science. - : IEEE. - 0018-9499 .- 1558-1578. ; 60:3, s. 2352-2356
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Tidskriftsartikel (refereegranskat)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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