5 research outputs found
Application of Proton Irradiation in the Study of Accelerated Radiation Ageing in a GaAs Semiconductor
Proton irradiation experiments have been used as a surrogate for studying radiation effects
in numerous materials for decades. The abundance and accessibility of proton accelerators make
this approach convenient for conducting accelerated radiation ageing studies. However, developing
new materials with improved radiation stability requires numerous model materials, test samples,
and very effective utilization of the accelerator beam time. Therefore, the question of optimal beam
current, or particle flux, is critical and needs to be adequately understood. In this work, we used
5 MeV protons to introduce displacement damage in gallium arsenide samples using a wide range
of flux values. Positron annihilation lifetime spectroscopy was used to quantitatively assess the
concentration of radiation-induced survived vacancies. The results show that proton fluxes in range
between 1011 and 1012 cmâ2 .sâ1 lead to a similar concentration of monovacancies generated in
the GaAs semiconductor material, while a further increase in the flux leads to a sharp drop in
this concentration
Application of Proton Irradiation in the Study of Accelerated Radiation Ageing in a GaAs Semiconductor
Proton irradiation experiments have been used as a surrogate for studying radiation effects in numerous materials for decades. The abundance and accessibility of proton accelerators make this approach convenient for conducting accelerated radiation ageing studies. However, developing new materials with improved radiation stability requires numerous model materials, test samples, and very effective utilization of the accelerator beam time. Therefore, the question of optimal beam current, or particle flux, is critical and needs to be adequately understood. In this work, we used 5 MeV protons to introduce displacement damage in gallium arsenide samples using a wide range of flux values. Positron annihilation lifetime spectroscopy was used to quantitatively assess the concentration of radiation-induced survived vacancies. The results show that proton fluxes in range between 1011 and 1012 cm−2.s−1 lead to a similar concentration of monovacancies generated in the GaAs semiconductor material, while a further increase in the flux leads to a sharp drop in this concentration
The HEV Ventilator: at the interface between particle physics and biomedical engineering.
A high-quality, low-cost ventilator, dubbed HEV, has been developed by the particle physics community working together with biomedical engineers and physicians around the world. The HEV design is suitable for use both in and out of hospital intensive care units, provides a variety of modes and is capable of supporting spontaneous breathing and supplying oxygen-enriched air. An external air supply can be combined with the unit for use in situations where compressed air is not readily available. HEV supports remote training and post market surveillance via a Web interface and data logging to complement standard touch screen operation, making it suitable for a wide range of geographical deployment. The HEV design places emphasis on the ventilation performance, especially the quality and accuracy of the pressure curves, reactivity of the trigger, measurement of delivered volume and control of oxygen mixing, delivering a global performance which will be applicable to ventilator needs beyond the COVID-19 pandemic. This article describes the conceptual design and presents the prototype units together with a performance evaluation