scholarly journals Silent Discharges in Ozonisers and CO2 Lasers

1995 ◽  
Vol 48 (3) ◽  
pp. 411 ◽  
Author(s):  
S Yagi ◽  
M Kuzumoto
Keyword(s):  
High Efficiency ◽  
High Energy ◽  
The Other ◽  
Laser Medium ◽  
Narrow Gap ◽  
Co2 Lasers ◽  
High Excitation ◽  
Dielectric Barrier ◽  
High Energy Electrons ◽  
Very High

Dielectric barrier ac discharges (silent discharges) have been developed to optimise the performance of ozonisers and C02 lasers. The characteristics and properties of the discharge are discussed and examined in the light of experimental results. The frequency of the applied voltage and gap length are around 1 kHz and 1 mm for the ozoniser and around 100 kHz and several em for the C02 laser. We have found that ozone is produced with high efficiency by using high energy electrons in a narrow gap. On the other hand, for C02 lasers, a high excitation efficiency is achieved by specifying the laser medium gas at very high N2 concentrations in a long gap.

scholarly journals Dosimetry and radioprotection evaluations of very high energy electron beams

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Thongchai A. M. Masilela ◽  
Rachel Delorme ◽  
Yolanda Prezado
Keyword(s):  
Neutron Yield ◽  
High Energy ◽  
Clinical Implementation ◽  
Dose Equivalent ◽  
Concrete Wall ◽  
Promising Alternative ◽  
High Energy Electrons ◽  
Ambient Dose Equivalent ◽  
Very High Energy ◽  
Very High

AbstractVery high energy electrons (VHEEs) represent a promising alternative for the treatment of deep-seated tumors over conventional radiotherapy (RT), owing to their favourable dosimetric characteristics. Given the high energy of the electrons, one of the concerns has been the production of photoneutrons. In this article we explore the consequence, in terms of neutron yield in a water phantom, of using a typical electron applicator in conjunction with a 2 GeV and 200 MeV VHEE beam. Additionally, we evaluate the resulting ambient neutron dose equivalent at various locations between the phantom and a concrete wall. Through Monte Carlo (MC) simulations it was found that an applicator acts to reduce the depth of the dose build-up region, giving rise to lower exit doses but higher entrance doses. Furthermore, neutrons are injected into the entrance region of the phantom. The highest dose equivalent found was approximately 1.7 mSv/Gy in the vicinity of the concrete wall. Nevertheless, we concluded that configurations of VHEEs studied in this article are similar to conventional proton therapy treatments in terms of their neutron yield and ambient dose equivalent. Therefore, a clinical implementation of VHEEs would likely not warrant additional radioprotection safeguards compared to conventional RT treatments.

scholarly journals Back to the Future: Very High-Energy Electrons (VHEEs) and Their Potential Application in Radiation Therapy

Cancers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 4942
Author(s):  
Maria Grazia Ronga ◽  
Marco Cavallone ◽  
Annalisa Patriarca ◽  
Amelia Maia Leite ◽  
Pierre Loap ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Current Knowledge ◽  
High Energy ◽  
High Dose Rate ◽  
Point Of View ◽  
High Dose ◽  
Dose Rates ◽  
High Energy Electrons ◽  
Very High Energy ◽  
Very High

The development of innovative approaches that would reduce the sensitivity of healthy tissues to irradiation while maintaining the efficacy of the treatment on the tumor is of crucial importance for the progress of the efficacy of radiotherapy. Recent methodological developments and innovations, such as scanned beams, ultra-high dose rates, and very high-energy electrons, which may be simultaneously available on new accelerators, would allow for possible radiobiological advantages of very short pulses of ultra-high dose rate (FLASH) therapy for radiation therapy to be considered. In particular, very high-energy electron (VHEE) radiotherapy, in the energy range of 100 to 250 MeV, first proposed in the 2000s, would be particularly interesting both from a ballistic and biological point of view for the establishment of this new type of irradiation technique. In this review, we examine and summarize the current knowledge on VHEE radiotherapy and provide a synthesis of the studies that have been published on various experimental and simulation works. We will also consider the potential for VHEE therapy to be translated into clinical contexts.

Very High Efficiency High-Energy Frequency Doubling in the Alisé Facility

2010 ◽  
Author(s):  
Gabriel Mennerat ◽  
Jacques Rault ◽  
Odile Bonville ◽  
Philippe Canal ◽  
Olivier Hartmann ◽  
...  
Keyword(s):  
High Efficiency ◽  
Frequency Doubling ◽  
High Energy ◽  
Very High

scholarly journals Toward an effective use of laser-driven very high energy electrons for radiotherapy: Feasibility assessment of multi-field and intensity modulation irradiation schemes

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Luca Labate ◽  
Daniele Palla ◽  
Daniele Panetta ◽  
Federico Avella ◽  
Federica Baffigi ◽  
...  
Keyword(s):  
High Energy ◽  
High Dose Rate ◽  
High Dose ◽  
Feasibility Assessment ◽  
High Energy Electrons ◽  
Very High Energy ◽  
Effective Use ◽  
Dose Deposition ◽  
Therapeutic Doses ◽  
Very High

Abstract Radiotherapy with very high energy electrons has been investigated for a couple of decades as an effective approach to improve dose distribution compared to conventional photon-based radiotherapy, with the recent intriguing potential of high dose-rate irradiation. Its practical application to treatment has been hindered by the lack of hospital-scale accelerators. High-gradient laser-plasma accelerators (LPA) have been proposed as a possible platform, but no experiments so far have explored the feasibility of a clinical use of this concept. We show the results of an experimental study aimed at assessing dose deposition for deep seated tumours using advanced irradiation schemes with an existing LPA source. Measurements show control of localized dose deposition and modulation, suitable to target a volume at depths in the range from 5 to 10 cm with mm resolution. The dose delivered to the target was up to 1.6 Gy, delivered with few hundreds of shots, limited by secondary components of the LPA accelerator. Measurements suggest that therapeutic doses within localized volumes can already be obtained with existing LPA technology, calling for dedicated pre-clinical studies.

scholarly journals Thermodynamic Model of a Very High Efficiency Power Plant based on a Biomass Gasifier, SOFCs, and a Gas Turbine

2012 ◽  
Vol 1 (2) ◽  
pp. 51-55 ◽  
Author(s):  
P V Aravind ◽  
C Schilt ◽  
B Türker ◽  
T Woudstra
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
High Efficiency ◽  
Heat Pipes ◽  
The Other ◽  
Gasification Process ◽  
Sofc Anode ◽  
Exergy Losses ◽  
Very High ◽  
Sofc Stacks

Thermodynamic calculations with a power plant based on a biomass gasifier, SOFCs and a gas turbine are presented. The SOFC anode off-gas which mainly consists of steam and carbon dioxides used as a gasifying agent leading to an allothermal gasification process for which heat is required. Implementation of heat pipes between the SOFC and the gasifier using two SOFC stacks and intercooling the fuel and the cathode streams in between them has shown to be a solution on one hand to drive the allothermal gasification process and on the other hand to cool down the SOFC. It is seen that this helps to reduce the exergy losses in the system significantly. With such a system, electrical efficiency around 73% is shown as achievable.

OC-0581: Dosimetry of 100 ñ 250 MeV Very High Energy Electrons (VHEE) as a new treatment modality for radiotherapy

2014 ◽  
Vol 111 ◽  
pp. S228
Author(s):  
A. Subiel ◽  
V. Moskvin ◽  
S. Cipiccia ◽  
G.H. Welsh ◽  
A. Sorensen ◽  
...  
Keyword(s):  
Treatment Modality ◽  
High Energy ◽  
High Energy Electrons ◽  
Very High Energy ◽  
New Treatment ◽  
Very High
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