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A single-crystal diamond sample grown by highpressure high temperature (HPHT) technique was used for the fabrication of a metal-semiconductor-metal photoconductor. The sample quality was evaluated by means of spectral photocurrent measurements highlighting the presence of a significant density of defect states within the diamond bandgap, responsible for trapmediated conduction mechanisms. The photoconductor was fully characterized under 6 MeV pulsed X-rays, sourced by a medical linear accelerator, in the 0.05 – 10 Gy and 1 – 6 Gy/min dose and dose-rate ranges, respectively. Photocurrent measurements performed with a conventional precision electrometer showed that the detector performance is strongly affected by charge-trapping phenomena, resulting in a sub-linear dependence with the doserate (power-law dependence with an exponent of 0.86). Measurements were repeated in the same experimental conditions by coupling the detector to a specifically developed gatedintegrator, allowing for a synchronous integration of photocurrent pulses (limited to 40 μs) centered on each impinging X-ray pulse. In this case, the detector photoresponse showed an excellent linearity with both the dose and the dose-rate (power-law dependence with 1.0009 ± 0.0004 and 1.009 ± 0.005 exponents, respectively). Significantly, the proposed synchronous integration technique is then able to mitigate the detrimental effect that defects have on detector performance. The proposed method paves therefore the way to the exploitation of HPHT-diamond as a lowcost alternative to single-crystal CVD-diamond for the fabrication of accurate and linear X-ray dosimeters.

X-ray photoresponse of κ-Ga2O3 is investigated for the first time. Results show that κ-Ga2O3 is a versatile material for the development of high-performance direct X-ray detectors.

The widespread diffusion of precision radiotherapy techniques, geared toward the release of larger dose gradients in shorter time frames, is leading to new challenges in dosimetry. Accurate dose measurements are essential to check for beam anomalies and inaccuracies to ensure treatment efficacy and patient safety during radiotherapy. This work describes the main features of a diamond dosimeter coupled to an extremely compact front-end electronics. The detection system was tested under the X-ray pulses generated by a medical LINAC for both the 6 MV and the 18 MV accelerating voltages. Located in the LINAC's bunker, it eliminates the need for a long cable connection between the detector and the electronics, detrimental for the system response speed. Signal acquisition was performed synchronously with the impinging X-ray pulses with a sampling period as low as 20 ?s, allowing for a real-time beam monitoring. The dosimeter demonstrated a very good stability despite the high value of the absorbed dose during the performed experiments (~100 Gy). The measured dose-per-pulse values of 278 ?Gy and 556 ?Gy at 6 MV and 18 MV, respectively, are in excellent agreement with the nominal values expected for the LINAC apparatus used for the tests. In addition to single-pulse measurements, fundamental for dynamic radiotherapy, the proposed system also allows for the calculation of both the total collected charge and the photocurrent generated by the detector. In this regard, despite the compactness, it demonstrates its effectiveness as a tool for source diagnostics in terms of both beam intensity and emission timing.

Radiotherapy is now recognized as a pillar in the fight against cancer. Two different types are currently used in clinical practice: (1) external beam radiotherapy, using high-energy X-rays or electron beams, both in the MeV-range, and (2) intraoperative radiotherapy, using low-energy X-rays (up to 50 keV) and MeV-range electron beams. Versatile detectors able to measure the radiation dose independently from the radiation nature and energy are therefore extremely appealing to medical physicists. In this work, a dosimeter based on a high-quality single-crystal synthetic diamond sample was designed, fabricated and characterized under low-energy X-rays, as well as under high-energy pulsed X-rays and electron beams, demonstrating excellent linearity with radiation dose and dose-rate. Detector sensitivity was measured to be 0.299 ± 0.002 µC/Gy under 6 MeV X-ray photons, and 0.298 ± 0.004 µC/Gy under 6 MeV electrons, highlighting that the response of the diamond dosimeter is independent of the radiation nature. Moreover, in the case of low-energy X-rays, an extremely low limit of detection (23 nGy/s) was evaluated, pointing out the suitability of the device to radiation protection dosimetry.

Background: Propeller-related injuries from motorboats are a major cause of injury in recreational water activities including severe and multiple lacerations that can promote scarring, blood loss, traumatic, or surgical amputations. The real incidence of these accidents is still unclear. The authors here present a systematic review of the literature, focusing on head injury, and related recommendations for its evaluation and management, also reporting a case of a female patient injured by a motorboat propeller. Methods: A systematic literature review was conducted according to the preferred reporting items for systematic reviews and meta-analyses statement, with no limits in terms of publication date. The following Mesh and free text terms were identified: “motorboat and propeller and injuries” (107 results). Results: A total of 12 papers were included in this systematic review. Only few case reports describing traumatic brain injury (TBI) have been documented. Out of a total of 90 cases analyzed, only five cases with TBI were reported. The authors also reported a case of a 12-year-old female, that during a boat trip, reported a severe polytrauma with concussive head trauma from a penetrating left fronto-temporo-parietal lesion, left mammary gland trauma and fracture of the left hand from falling into the water and impact with a motorboat propeller. She underwent an urgent left fronto-temporo-parietal decompressive craniectomy and then surgery with a multidisciplinary team. At the end of the surgical procedure, the patient was transferred to the pediatric intensive care unit. She was discharged on postoperative day 15. The patient was able to walk without assistance, with mild right hemiparesis and persistence of aphasia nominum. Conclusion: Motorboat propeller injuries can result in extensive damage to soft tissue and bones with severe functional disability, amputations, and high mortality. There are still no recommendations and protocols for the management of motorboat propeller related injuries. Although there are several potential solutions that aim to prevent or ease motorboat-propeller injuries, there are still lack of consistent regulations.

Modern dynamic radiotherapies in cancer treatment are oriented to release high dose values in the shortest irradiation time. For these techniques, fast detectors and dedicated conditioning electronics will play a fundamental role for beam diagnostics to verify the necessary quality assurance requirements of treatments. This work describes a measurement system based on a single-crystal synthetic diamond able to monitor the dose released by each X-ray pulse generated by a medical LINAC. A gated-integration method, performed by a specifically designed electronics, has been used to measure the charge photogenerated in diamond by each impinging X-pulse. Exploiting the synchronization signal available in a LINAC apparatus, our system allows performing pulse-beam diagnostics with an acquisition time limited to the period around each pulse. Therefore, the proposed solution represents an effective tool for real-time dosimetry in modern radiotherapy applications and assures a better accuracy in comparison to conventional electrometer-based measurement systems that require longer acquisition periods.

This work aims at describing a dose-measurement system based on a high-quality single-crystal synthetic diamond coupled to specifically-designed front-end electronics and timing circuitry. By exploiting the pulsed nature of radiation sourced by LINACs, the electronics performs a synchronous detection of charge-carriers generated by the diamond detector on which pulsed X-rays impinge. Synchronous detection would assure superior level of accuracy, sensitivity, and dynamics in comparison to conventional continuous-integration solutions, since the measurements are affected by environmental noise to a lesser extent. In addition, preliminary characterization described in this paper highlights the feasibility of a measurement system capable of providing information on the dose delivered at the level of a single X-ray pulse. In this context, the proposed system would be able to respond to the specific needs of accurate dose diagnostics for modern radiotherapy treatments where radiation-dose is characterized by a complex shaped distribution and steep gradients.

In this work we analyze the behavior of pressure sensors based on membranes of chemically very inert materials and robust to atmospheric agents with non-neutral pH. The selected material for cheapness and chemical stability for the manufacture of low-cost pressure sensors is Silicon Carbide, even if a special section is dedicated to diamond membranes pressure sensors because of its unique chemical inertness. Considering also the electromagnetic noise as an aggressive element of the measurement environment, the low-cost reproduction via sensor - optical fiber coupling of a low-finesse Fabry-Perot interferometer was chosen as the reading setup. SiC membranes are realized by nanosecond LASER processing while those in diamond are made by CVD deposition and microelectronic etching techniques.

An extremely compact gated integrator prototype has been realized and preliminarily characterized. Front-end section of the circuit is based on the high precision integrator IVC102, whereas the analog to digital conversion and data-acquisition, as well as the timing control, are performed by an LCP845 microcontroller. The system synchronizes signal detection with an external trigger generated in coincidence with the source pulse, i.e. the gated integrator amplifies the signal only when a pulse is generated, increasing significantly the signal-to-noise ratio. As a consequence, the proposed circuitry would represent an affordable, sensitive, and cost-effective alternative to the continuous-time regime measurement-technique largely adopted, for example, in radiation dosimetry.

Gated integrating measurement method represents a widely used approach when fast, repetitive analogue signals are concerned. In this work a compact synchronized gated-integrator prototype has been realized and preliminary characterized. Front-end electronics is based on the mature high-precision switched-integrator transimpedance-amplifier IVC102 whose output is connected to a precision LT1911 inverting amplifier, whereas analogue-to-digital conversion, as well as timing control circuitry, are performed by a high-efficiency LPC845 microcontroller. Synchronizing signal detection with the external trigger generated in coincidence with a source, the proposed circuitry amplifies and integrates the signal only when the pulse is generated, displaying excellent performances in terms of linearity, sensitivity and signal-to-noise ratio. Hence, the proposed solution represents an affordable alternative to continuous-time regime measurement-techniques, usually adopted in radiation dosimetry where accuracy and sensitivity are strict requirements for treatment quality assurance.

Pressure sensors based on diamond membranes were designed and tested for gas pressure measurement up to 6.8 MPa. The diamond film (2” diameter, 6 μm thickness)—grown by microwave plasma chemical vapor deposition on a silicon substrate—was a starting material to produce an array of membranes with different diameters in the 130–400 μm range, in order to optimize the sensor performance. Each 5 mm × 5 mm sensing element was obtained by subsequent silicon slicing. The fixed film thickness, full-scale pressure range, and sensor sensitivity were established by a proper design of the diameter of diamond membrane which represents the sensing element for differential pressure measurement. The pressure-induced deflection of the membrane was optically measured using a Fabry-Pérot interferometer formed by a single mode optical fiber front surface and the deflecting diamond film surface. The optical response of the system was numerically simulated using geometry and the elastic properties of the diamond diaphragm, and was compared with the experiments. Depending on the diamond membrane’s diameter, the fabricated sensors displayed a good modulation depth of response over different full-scale ranges, from 3 to 300 bar. In view of the excellent mechanical, thermal, and chemical properties of diamond, such pressure sensors could be useful for performance in a harsh environment.

Thin polycrystalline diamond films chemically vapor deposited on thinned silicon substrates were used as membranes for pressure sensor fabrication by means of selective chemical etching of silicon. The sensing element is based on a simple low-finesse Fabry&ndash, P&eacute, rot (FP) interferometer. The FP cavity is defined by the end-face of a single mode fiber and the diamond diaphragm surface. Hence, pressure is evaluated by measuring the cavity length by an optoelectronic system coupled to the single mode fiber. Exploiting the excellent properties of Chemical Vapor Deposition (CVD) diamond, in terms of high hardness, low thermal expansion, and ultra-high thermal conductivity, the realized sensors have been characterized up to 16.5 MPa at room temperature. Preliminary characterizations demonstrate the feasibility of such diamond-on-Si membrane structure for pressure transduction. The proposed sensing system represents a valid alternative to conventional solutions, overcoming the drawback related to electromagnetic interference on the acquired weak signals generated by standard piezoelectric sensors.