Search

We present the set-up and performances of the TOP-IMPLART accelerator as a proton source for radiation testing of space components. The TOP-IMPLART proton accelerator is a pulsed fully linear machine aimed at active intensity modulated proton therapy with a final energy of 150 MeV under development at ENEA Frascati Research Centre. Presently the machine offers a beam extraction point on the horizontal line at 35 MeV, with a current up to 50 µA in a 3 µs long pulse and maximum repetition frequency of 50 Hz. An in-air irradiation set-up 1.8 m downstream the accelerator exit window is available with an effective beam energy of about 30 MeV, ±5% transverse homogeneity on a 40 mm diameter beam spot, and intensity repeatability within ±5%. While the proton beams main characteristics (energy, intensity, average fluence) are the same of conventional cyclotron-based cancer treatment facilities, already used for space components qualification, its time structure is significantly different, with high instantaneous dose rate. This research aims at demonstrating the possibility to use an accelerator with these characteristics for radiation hardness assurance testing. A commercial 6-axis integrated MEMS inertial navigation system (accelerometer, gyroscope) was selected as device under test. These devices could be used for example as sensors for attitude determination in University Cubesat missions. Irradiation with proton beams allows simultaneous exploration of total dose, displacement damage and some single-event effect of such components. The results of experimental tests aimed to define an operational procedure are reported: the irradiation set-up is described in detail and the characterization of radiation effect on the component is reported highlighting the consequence of the device performance degradation in terms of the overall navigation system accuracy. These results are considered a first step towards the use of the TOP-IMPLART linear accelerator as a meaningful alternative to traditional cyclotron for proper space qualification of electronic components.

The purpose of the BIOxTREME project, launched by ENEA (Italian National Agency for New Technologies, Energy and Sustainable Economic Development) and funded by ASI (Italian Space Agency), is to formulate new biological drugs having a stimulant activity on the immune system, finalizing the production for a "ready to use" resource in Bioregenerative Life Support Systems (BLSSs) for space missions intended for long-term duration, in deep space, and with multiple crews. One of the project tasks is to study the effects of physical insults on plants, trying to simulate cosmic environment on the production platforms exposing biological material to ionizing radiation, static magnetic fields and microgravity. In order to examine the biological effects, to test plant radio-resistance and to build dose-response curves we carried out proton irradiations of anthocyanin rich (red) "hairy roots" derived from the tomato cultivar Micro-Tom with different proton energies for several doses with the TOP-IMPLART accelerator at the ENEA Frascati Research center. The biological samples were placed in a holder specially made in a movable real-time monitoring chamber calibrated in dose. The fluence-homogeneity measurements over the sample and the calibration of the monitoring system were performed using GafChromic EBT3 films, placed in air in the same position as the biological samples to be irradiated. The present paper describes the experimental set-up and reports the preliminary results. Copyright © 2015 CC-BY-3.0 and by the respective authors.

In the ENEA-Frascati research center a linear accelerator for proton therapy is under development in the framework of TOP-IMPLART Project carried out by ENEA in collaboration with ISS and IRE-IFO. The machine is based on a 7 MeV injector operating at a frequency of 425 MHz followed by a sequence of 2997.92 MHz accelerating modules. Five 10 MW klystrons will be used to power all high frequency structures up to a beam energy of 150 MeV. The maximum repetition frequency is 100 Hz and the pulse duration is 4 μs. The RF amplitude and phase stability requirements of the accelerating field are within ±2% and ±2 degrees respectively. For therapeutic use the beam energy will be varied between 85 and 150 MeV by switching off the last modules and varying the electric field amplitude in the last module switched on. Fast control of the RF power supplied to the individual structures allows an energy variation on a pulse by pulse basis; furthermore the system must be able to control the RF phase between accelerating structures. This work describes the RF power distribution scheme and the RF phase and amplitude monitoring system implemented into an embedded control system. Copyright © 2015 CC-BY-3.0 and by the respective authors.

We have investigated the effects of deep hydrogen implantation into n- and p-type silicon wafers ((100) oriented, with resistivity in the 1-20 Ω·cm range). Deep implantation has been achieved using the Hitachi-AccSys PL-7 RF LINAC set for 3.0 MeV beam energy, degraded to 1.8 MeV. Hydrogen has been implanted 30 μm below the wafer surface with an implant dose (fluence) >5×1015 cm-2. Samples were partly covered by a metal mask during implant. Porous silicon has been formed on the exposed samples to study the effect of hydrogen irradiation. We have found that porous silicon formation is inhibited in the irradiated areas on p-type silicon and promoted on the n-type one. Copyright © 2015 CC-BY-3.0 and by the respective authors.

Objetivos: Evaluar la composición microbiológica y los parámetros clínicos de bolsas periodontales ≥5 mm de profundidad al inicio, 1 semana, 3 y 12 meses post raspado y alisado radicular. Materiales y Métodos: Se tomaron registros clínicos y muestras de placa subgingival de 44 sitios de pacientes con diagnóstico de periodontitis crónica. Se identificaron por técnica de Reacción en Cadena de la Polimerasa (PCR) patógenos putativos periodontales: Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Treponema denticola (Td), Tannerella forsythia (Tf) y Prevotella intermedia (Pi). Los pacientes recibieron terapia mecánica periodontal y fueron reevaluados a los 7 días, 3 y 12 meses. Resultados: Luego del tratamiento, todos los parámetros clínicos (Placa Bacteriana, Hemorragia, Supuración, Profundidad al Sondaje y Nivel de Inserción Clínica) se redujeron significativamente y los valores obtenidos se mantuvieron hasta los 12 meses. Al inicio, las especies bacterianas prevalentes fueron Pg, presente en 66% de los sitios, Tf (55%) y Td (41%). Los sitios más profundos se relacionaron con las asociaciones Tf-Td (6.8 mm) y Tf-Td-Pi (7 mm). Post terapia, el número de sitios positivos para Td, Tf y Pg se redujo significativamente. Conclusiones: El raspado y alisado radicular mejoró significativamente los parámetros clínicos y redujo la prevalencia de los patógenos periodontales Pg, Tf y Td en bolsas periodontales profundas. Los resultados obtenidos se mantuvieron hasta los 12 meses. No se detectaron mayores pérdidas de inserción clínica en el 86% de los sitios a 3 meses y en 79% a los 12 meses. Los sitios en los que el tratamiento no fue efectivo en la eliminación de patógenos a los 12 meses desarrollaron mayores profundidades de sondaje. Objectives: To evaluate the microbial composition and clinical parameters of periodontal pockets with probing depth ≥5 mm at baseline, 1 week, 3 and 12 months after scaling and root planning. Methods: Clinical parameters were measured and bacterial samples were collected from 44 sites in 11 patients with chronic periodontitis. By means of Polymerase Chain Reaction (PCR) the presence of Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Treponema denticola (Td), Tannerella forsythia (Tf) and Prevotella intermedia (Pi) was estimated. The patients received mechanical periodontal therapy and were evaluated after 1 week, 3 months and 12 months. Results: After treatment, all clinical parameters (Plaque, Bleeding on Probing, Supuration, Probing Pocket Depth and Clinical Attachment Level) were significantly reduced, and the values obtained were maintained up to the 12 months that the study lasts. At baseline, the most prevalent species were Pg, present in 66% of the sites, Tf (55%) and Td (41%). The deepest sites were related to the association Tf-Td (6.8 mm) and Tf-Td-Pi (7 mm). The number of positive sites for Td, Tf and Pg was significantly reduced after therapy. Conclusions: Scaling and root planning improve significantly clinical parameters as well as reduce the prevalence of periodontal pathogens Pg, Td and Tf in deep periodontal pockets. The results obtained were maintained up to 12 months. No further clinical attachment loss was found in 86% of the sites at 3 months and 79% at 12 months. The sites where the treatment failed in removing pathogens developed at 12 months greater probing pocket depths.

ResumenObjetivosEvaluar la composición microbiológica y los parámetros clínicos de bolsas periodontales ≥5mm de profundidad al inicio, 1 semana, 3 y 12 meses post raspado y alisado radicular.Materiales y MétodosSe tomaron registros clínicos y muestras de placa subgingival de 44 sitios de pacientes con diagnóstico de periodontitis crónica. Se identificaron por técnica de Reacción en Cadena de la Polimerasa (PCR) patógenos putativos periodontales: Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Treponema denticola (Td), Tannerella forsythia (Tf) y Prevotella intermedia (Pi). Los pacientes recibieron terapia mecánica periodontal y fueron reevaluados a los 7 días, 3 y 12 meses.ResultadosLuego del tratamiento, todos los parámetros clínicos (Placa Bacteriana, Hemorragia, Supuración, Profundidad al Sondaje y Nivel de Inserción Clínica) se redujeron significativamente y los valores obtenidos se mantuvieron hasta los 12 meses. Al inicio, las especies bacterianas prevalentes fueron Pg, presente en 66% de los sitios, Tf (55%) y Td (41%). Los sitios más profundos se relacionaron con las asociaciones Tf-Td (6.8mm) y Tf-Td-Pi (7mm). Post terapia, el número de sitios positivos para Td, Tf y Pg se redujo significativamente.ConclusionesEl raspado y alisado radicular mejoró significativamente los parámetros clínicos y redujo la prevalencia de los patógenos periodontales Pg, Tf y Td en bolsas periodontales profundas. Los resultados obtenidos se mantuvieron hasta los 12 meses. No se detectaron mayores pérdidas de inserción clínica en el 86% de los sitios a 3 meses y en 79% a los 12 meses. Los sitios en los que el tratamiento no fue efectivo en la eliminación de patógenos a los 12 meses desarrollaron mayores profundidades de sondaje.AbstractObjectivesTo evaluate the microbial composition and clinical parameters of periodontal pockets with probing depth ≥5mm at baseline, 1 week, 3 and 12 months after scaling and root planning.MethodsClinical parameters were measured and bacterial samples were collected from 44 sites in 11 patients with chronic periodontitis. By means of Polymerase Chain Reaction (PCR) the presence of Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Treponema denticola (Td), Tannerella forsythia (Tf) and Prevotella intermedia (Pi) was estimated. The patients received mechanical periodontal therapy and were evaluated after 1 week, 3 months and 12 months.ResultsAfter treatment, all clinical parameters (Plaque, Bleeding on Probing, Supuration, Probing Pocket Depth and Clinical Attachment Level) were significantly reduced, and the values obtained were maintained up to the 12 months that the study lasts. At baseline, the most prevalent species were Pg, present in 66% of the sites, Tf (55%) and Td (41%). The deepest sites were related to the association Tf-Td (6.8mm) and Tf-Td-Pi (7mm). The number of positive sites for Td, Tf and Pg was significantly reduced after therapy.ConclusionsScaling and root planning improve significantly clinical parameters as well as reduce the prevalence of periodontal pathogens Pg, Td and Tf in deep periodontal pockets. The results obtained were maintained up to 12 months. No further clinical attachment loss was found in 86% of the sites at 3 months and 79% at 12 months. The sites where the treatment failed in removing pathogens developed at 12 months greater probing pocket depths.

MOPEB004; International audience