scholarly journals Stray radiation produced in FLASH electron beams characterized by the MiniPIX Timepix3 Flex detector

2022 ◽  
Vol 17 (01) ◽  
pp. C01003
Author(s):  
C. Oancea ◽  
C. Bălan ◽  
J. Pivec ◽  
C. Granja ◽  
J. Jakubek ◽  
...  
Keyword(s):  
Electron Beams ◽  
Spectral Characteristics ◽  
High Dose Rate ◽  
Secondary Beam ◽  
High Dose ◽  
Pixel Detector ◽  
Dose Rates ◽  
Radiation Fields ◽  
Silicon Sensors ◽  
Asic Chip

Abstract This work aims to characterize ultra-high dose rate pulses (UHDpulse) electron beams using the hybrid semiconductor pixel detector. The Timepix3 (TPX3) ASIC chip was used to measure the composition, spatial, time, and spectral characteristics of the secondary radiation fields from pulsed 15–23 MeV electron beams. The challenge is to develop a single compact detector that could extract spectrometric and dosimetric information on such high flux short-pulsed fields. For secondary beam measurements, PMMA plates of 1 and 8 cm thickness were placed in front of the electron beam, with a pulse duration of 3.5 µs. Timepix3 detectors with silicon sensors of 100 and 500 µm thickness were placed on a shifting stage allowing for data acquisition at various lateral positions to the beam axis. The use of the detector in FLEXI configuration enables suitable measurements in-situ and minimal self-shielding. Preliminary results highlight both the technique and the detector’s ability to measure individual UHDpulses of electron beams delivered in short pulses. In addition, the use of the two signal chains per-pixel enables the estimation of particle flux and the scattered dose rates (DRs) at various distances from the beam core, in mixed radiation fields.

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 Fractionated versus single-dose total body irradiation at low and high dose rates to condition canine littermates for DLA-identical marrow grafts

Blood ◽  
1994 ◽  
Vol 83 (11) ◽  
pp. 3384-3389 ◽  
Author(s):  
R Storb ◽  
RF Raff ◽  
FR Appelbaum ◽  
HJ Deeg ◽  
TC Graham ◽  
...  
Keyword(s):  
Dna Repair ◽  
Single Dose ◽  
Dose Rate ◽  
Total Body Irradiation ◽  
High Dose Rate ◽  
Lymphoid Cells ◽  
High Dose ◽  
Dose Rates ◽  
Total Body ◽  
Allogeneic Marrow

Abstract We explored in dogs the immunosuppressive properties of 450 cGy total body irradiation (TBI) delivered from two opposing 60Co sources, as assessed by the criterion of successful engraftment of allogeneic genotypically DLA-identical littermate marrow. Two questions were asked in this study. Firstly, does dose rate affect the immunosuppressive effect of TBI when administered in a single dose? Secondly, does fractionation alter the immunosuppression of TBI when delivered at a very fast dose rate? Dose rates studied included 7 and 70 cGy/min, and fractionation involved four fractions of 112.5 cGy each, with 6-hour minimum interfraction intervals. Six of 7 dogs receiving 450 cGy single- dose TBI at 70 cGy/min showed sustained engraftment of the allogeneic marrow, compared with 1 of 7 dogs receiving single-dose TBI at 7 cGy/min (P = .01). Fractionated TBI at 70 cGy/min resulted in sustained allogeneic engraftment in 3 of 10 dogs, a result that was statistically significantly worse than that with single-dose TBI at 70 cGy/min (P = .03) and not statistically different (P = .24) from that with fractionated TBI delivered at 7 cGy/min (0 of 5 dogs engrafted). A single dose of 450 cGy of TBI delivered at a rate of 70 cGy/min is significantly more immunosuppressive than the same total dose delivered at 7 cGy/min. Fractionated TBI at 70 cGy/min is significantly less immunosuppressive than single-dose TBI at 70 cGy/min and not significantly different from fractionated TBI administered at 7 cGy/min. Results are consistent with the notion that significant DNA repair in lymphoid cells is possible during interfraction intervals at the relatively high dose rate of 70 cGy/min.

Electron and Beta Dose Rates of UO2 Pellet and Fuel Rod

2013 ◽  
Author(s):  
Guoqing Zhang ◽  
Xuexin Wang ◽  
Jiangang Zhang ◽  
Dajie Zhuang ◽  
Chaoduan Li ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Dose Rate ◽  
Radiation Protection ◽  
High Dose Rate ◽  
High Dose ◽  
Electron Dose ◽  
Dose Rates ◽  
Fuel Rod ◽  
Calculation Results ◽  
Beta Dose

The isotopes of uranium and their daughter nuclides inside the UO2 pellet emit mono-energetic electrons and beta rays, which generate rather high dose rate near the UO2 pellet and could cause exposure to workers. In this work calculations of electron dose rates have been carried out with Monte Carlo codes, MCNPX and Geant4, for a UO2 pellet and a fuel rod. Comparisons between calculations and measurements have been carried out to verify the calculation results. The results could be used to estimate the dose produced by electrons and beta rays, which could be used to make optimization for radiation protection purpose.

The Effects of Radiation on Intermediate Level Waste Forms

1988 ◽  
Vol 127 ◽  
Author(s):  
C. R. Wilding ◽  
D. C. Phillips ◽  
CE. Lyon
Keyword(s):  
High Pressures ◽  
High Dose Rate ◽  
High Dose ◽  
Dose Rates ◽  
Waste Forms ◽  
Wide Range ◽  
Fuel Ash ◽  
Effects Of Radiation ◽  
Alpha Irradiation ◽  
Furnace Slag

ABSTRACTThe effects of accelerated gamma and alpha irradiation experiments on cement grouts alone and grouts containing simulated combustible plutonium contaminated material (PCM) at a number of dose rates and under various environmental and confinement conditions are considered. Cracking and spallation can occur over a wide range of water/cement ratios at a high dose rate of 2.8 Gys-1 for grouts based on blast furnace slag compositions. Grouts based on pulverised fuel ash do not show any signs of spallationand cracking. One possible reason for this is the accumulation of radiolytic gases to high pressures in pores in the cement. It has been demonstrated that under some circumstances, at the Laboratory scale, PCM waste form can swell sufficiently to rupture its container and may disintegrate.

scholarly journals Nanoparticles synthesis by electron beam radiolysis

2014 ◽  
Vol 12 (7) ◽  
pp. 774-781 ◽  
Author(s):  
Ioan Călinescu ◽  
Diana Martin ◽  
Daniel Ighigeanu ◽  
Adina Gavrila ◽  
Adrian Trifan ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Electron Beam ◽  
Chemical Reduction ◽  
Absorbed Dose ◽  
Reduction Process ◽  
High Dose Rate ◽  
High Dose ◽  
Experimental Conditions ◽  
Dose Rates ◽  
Absorbed Dose Rates

AbstractElectron beam (EB) irradiation is a useful method to generate stable silver nanoparticles without the interference of inherent impurities generated from chemical reactions. Our experiments were carried out using linear electron beam accelerators with two different EB absorbed dose rates: 2 kGy min−1 and 7–8 kGy s−1, and with different absorbed dose levels. The optimum conditions for silver nanoparticles (AgNPs) generation by radiolysis, or by radiolysis combined with chemical reduction, were established. In order to obtain a good yield for AgNPs synthesized by radiolysis, a high dose rate is required, resulting in a rapid production process. At low absorbed dose rates, the utilization of a stabilization agent is advisable. By modifying the experimental conditions, the ratio between the chemical and radiolytic reduction process can be adjusted, thus it is possible to obtain nanoparticles with tailored characteristics, depending on the desired application.

Radiobiological characterization of the very high dose rate and dose per pulse electron beams produced by an IORT (intra operative radiation therapy) dedicated linac

2017 ◽  
Vol 6 (S5) ◽  
pp. S761-S768 ◽  
Author(s):  
Paola Scampoli ◽  
Carmela Carpentieri ◽  
Marco Giannelli ◽  
Vera Magaddino ◽  
Lorenzo Manti ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Dose Rate ◽  
Electron Beams ◽  
High Dose Rate ◽  
High Dose ◽  
Pulse Electron ◽  
Very High

High Dose Rate Oxygen Implantation for Formation of Silicon-on-Insulator Structures

1990 ◽  
Vol 201 ◽  
Author(s):  
E. Cortesi ◽  
F. Namavar ◽  
R. F. Pinizzotto ◽  
H. Yang
Keyword(s):  
Dose Rate ◽  
Silicon Surface ◽  
High Dose Rate ◽  
Silicon On Insulator ◽  
High Dose ◽  
Surface Oxide Layer ◽  
Dose Rates ◽  
Pit Formation ◽  
Lower Dose Rate ◽  
Very High

AbstractWe have studied Separation by IMplantation of OXygen (SIMOX) processes using very high dose rates (40–60 μA/cm2). For a dose of 4 × 1017 O+/cm2 at 160 keV, the structure formed by implantation at 50 μA/cm2 is very similar to that associated with lower dose rates. The same dose implanted at a dose rate of 60 μA/cm2, however, results in the formation of pits in the silicon surface as well as a somewhat different oxide structure. Implantation through a surface oxide layer appears to result in a structure similar to that associated with lower dose rate implantation. These and higher dose samples suggest that the threshold for pit formation is related to both dose rate and dose.

Radiological Control of Gold Octahedral and Prism Nanoparticles

2007 ◽  
Vol 1056 ◽  
Author(s):  
Tina M. Nenoff ◽  
Jason C. Jones ◽  
Paula P. Provencio ◽  
Donald T. Berry
Keyword(s):  
Dose Rate ◽  
High Dose Rate ◽  
Pure Gold ◽  
High Dose ◽  
Visible Absorption ◽  
Dose Rates ◽  
Radiation Induced ◽  
Radiological Control ◽  
Uv Visible ◽  
Short Time

ABSTRACTWe report on a fundamental morphology growth of gold-based nanoparticles by solution radiolysis. Radiolysis of pure gold-polymer solutions of different dose rates and aging time is examined. A detailed description will be presented of the experimentation, testing and analysis. In particular, we will present data on the formation of gold nano-octahedra and -prism particles. The γ-irradiations were carried out with a 60Co source of 1.345 × 105 Ci (Sandia National Laboratories Gamma Irradiation Facility (GIF). Nanoparticle characterization techniques included are UV-vis and TEM. Similar to what has been seen in earlier silver nanoparticle studies, dose rate dictates the size of nanoparticles formed. At high dose rate, all reducing species are produced and scavenged within a short time, and then coalesce into separate nanoparticles. At low dose rate, the coalescence process is faster than the production rate of the reducing radicals. The reduction of radicals occurs mainly on clusters already formed. The differences in the morphologies result from a combination of dose rate, aging and lack of radical scavengers (e.g. isopropyl alcohol), resulting in either gold nano-spheres, octahedral or prism nanoparticles. The progressive evolution with dose rate of the UV-visible absorption spectra of radiation-induced metal clusters is discussed.

Radiation chemistry of gaseous oxygen: experimental and calculated yields

1970 ◽  
Vol 48 (10) ◽  
pp. 1505-1514 ◽  
Author(s):  
C. Willis ◽  
A. W. Boyd ◽  
M. J. Young ◽  
D. A. Armstrong
Keyword(s):  
Cross Sections ◽  
Radiation Chemistry ◽  
High Dose Rate ◽  
High Dose ◽  
Gaseous Oxygen ◽  
Dose Rates ◽  
Computer Calculations ◽  
Experimental Yield ◽  
The Difference ◽  
Good Agreement

The yield of ozone from the radiolysis of gaseous oxygen has been measured at 1026–1027 eV g−1 s−1 to be G(O3) = 12.8 ± 0.6, in reasonable agreement with the value of 13.8 of Ghormley, Hochanadel, and Boyle (2a). At 1016 eV g−1 s−1, our results and re-examination of previous data give G(O3) = 6.2 ± 0.6. The same value is obtained at the high dose rates by the addition of electron scavengers. The difference in yields on going from high to low dose rates and the decrease with electron scavengers at the high dose rate is explained by differences in ion neutralization processes. These are supported by computer calculations. The mechanism of the neutralization steps is discussed in terms of the applicability of the electron jump theory and the effect of clustering of the ions.The proportion of energy lost to ionization, excitation, and subexcitation electrons is calculated. This is based on the W value, relative cross sections for ionization, and the potential energy curves for O2+ ions. A predicted yield on this basis is G(O3) = 14.0 ± 0.9, in fairly good agreement with the experimental yield.

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