Gamma and Alpha Radiolysis of Salt Brines

1984 ◽  
Vol 44 ◽  
Author(s):  
W. J. Gray ◽  
S. A. Simonson
Keyword(s):  
Redox Potential ◽  
High Dose Rate ◽  
High Dose ◽  
Permian Basin ◽  
Gamma Radiolysis ◽  
Basin Brine ◽  
Alpha Radiolysis ◽  
Gas Space ◽  
Very High ◽  
Gas Pressures

AbstractGamma radiolysis of Permian Basin brine leads to equilibrium gas pressure of about 100 atm. at 75°C and about 40 atm. at 150°C, providing the gas space is very small and/or the total dose is very high. Dose rate dependence is being investigated but is not yet established. Alpha radiolysis of Permian Basin brine is still being evaluated, but it is clear that equilibrium gas pressures will be much higher than with gamma radiolysis. In addition, alpha radiolysis of brine results in a very high solution redox potential. Gas compositions in all cases have been about two parts H2 to one part O2. Efforts to simulate these results with computer models have been quite successful.

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.

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 Enhancing radiosensitivity of melanoma cells through very high dose rate pulses released by a plasma focus device

PLoS ONE ◽  
2018 ◽  
Vol 13 (6) ◽  
pp. e0199312 ◽  
Author(s):  
Francesca Buontempo ◽  
Ester Orsini ◽  
Isabella Zironi ◽  
Lorenzo Isolan ◽  
Alessandra Cappellini ◽  
...  
Keyword(s):  
Dose Rate ◽  
Plasma Focus ◽  
Melanoma Cells ◽  
High Dose Rate ◽  
Plasma Focus Device ◽  
High Dose ◽  
Very High

Primary yields and mechanism in the radiolysis of gaseous ammonia

1969 ◽  
Vol 47 (16) ◽  
pp. 3007-3016 ◽  
Author(s):  
C. Willis ◽  
A. W. Boyd ◽  
O. A. Miller
Keyword(s):  
Dose Rate ◽  
Rate Constant ◽  
High Dose Rate ◽  
Radical Reactions ◽  
Gaseous Ammonia ◽  
High Dose ◽  
Ammonia Vapor ◽  
Radical Product ◽  
Very High

Ammonia vapor has been irradiated with single pulses of electrons at a very high dose rate (1027 eV g−1 s−1) with a Febetron 705. At this dose rate radical–product reactions are not significant. In pure ammonia, hydrogen, nitrogen, and hydrazine are produced and the yields found at 1027 eV g−1 s−1 are: G(H2) = 3.58 ± 0.08; G(N2) = 1.00 ± 0.05; G(N2H4) = 0.58 ± 0.05. The yields are independent of pressure from 1 to 5 atm and of temperature between 20 and 200 °C. Above 250 °C the yields of all three products increase significantly and this is due to reaction [1] competing with radical–radical reactions.[Formula: see text]A rate constant for this reaction has been determined,[Formula: see text]Product yields have been measured for ammonia–propene mixtures. These yields have allowed determination of the primary radiation yields GNH = 0.74; [Formula: see text]; GH = 4.8; and G(−NH3) = 5.4.

scholarly journals Biological and Mechanical Synergies to Deal With Proton Therapy Pitfalls: Minibeams, FLASH, Arcs, and Gantryless Rooms

2021 ◽  
Vol 10 ◽  
Author(s):  
Alejandro Mazal ◽  
Juan Antonio Vera Sanchez ◽  
Daniel Sanchez-Parcerisa ◽  
Jose Manuel Udias ◽  
Samuel España ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Proton Therapy ◽  
Target Volume ◽  
High Dose Rate ◽  
Clinical Applications ◽  
High Dose ◽  
Beam Path ◽  
Entrance Dose ◽  
Dose Constraints ◽  
Very High

Proton therapy has advantages and pitfalls comparing with photon therapy in radiation therapy. Among the limitations of protons in clinical practice we can selectively mention: uncertainties in range, lateral penumbra, deposition of higher LET outside the target, entrance dose, dose in the beam path, dose constraints in critical organs close to the target volume, organ movements and cost. In this review, we combine proposals under study to mitigate those pitfalls by using individually or in combination: (a) biological approaches of beam management in time (very high dose rate “FLASH” irradiations in the order of 100 Gy/s) and (b) modulation in space (a combination of mini-beams of millimetric extent), together with mechanical approaches such as (c) rotational techniques (optimized in partial arcs) and, in an effort to reduce cost, (d) gantry-less delivery systems. In some cases, these proposals are synergic (e.g., FLASH and minibeams), in others they are hardly compatible (mini-beam and rotation). Fixed lines have been used in pioneer centers, or for specific indications (ophthalmic, radiosurgery,…), they logically evolved to isocentric gantries. The present proposals to produce fixed lines are somewhat controversial. Rotational techniques, minibeams and FLASH in proton therapy are making their way, with an increasing degree of complexity in these three approaches, but with a high interest in the basic science and clinical communities. All of them must be proven in clinical applications.

ChemInform Abstract: VERY-HIGH-DOSE-RATE RADIOLYSIS OF N-BUTANE IN THE GAS PHASE, THE EFFECT OF THE ADDITION OF ELECTRON SCAVENGERS

1974 ◽  
Vol 5 (22) ◽  
Author(s):  
YOSHIHIKO HATANO ◽  
SATOSHI TAKAO ◽  
HIDEKI NAMBA ◽  
TAKUMI UENO ◽  
SHOJI SHIDA
Keyword(s):  
Dose Rate ◽  
Gas Phase ◽  
High Dose Rate ◽  
High Dose ◽  
Very High
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