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.

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 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

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.

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.

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 radiation chemistry of carbon monoxide at very high dose rates

1970 ◽  
Vol 48 (19) ◽  
pp. 3029-3033 ◽  
Author(s):  
C. Willis ◽  
O. A. Miller
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Excited State ◽  
Oxygen Atom ◽  
Dose Rate ◽  
Electron Accelerator ◽  
Radiation Chemistry ◽  
High Dose ◽  
Dose Rates ◽  
Very High

Carbon monoxide has been irradiated with single intense pulses from an electron accelerator at a dose rate of ~ 2 × 1027 eV g−1 s−1. The yield of carbon dioxide obtained was G(CO2) = 0.7 ± 0.1 with a very small yield of carbon suboxide, G(C3O2) ≤ 0.02.Addition of propene reduces the carbon dioxide yield to almost zero while addition of propane has no effect. This suggests that propene is acting as an oxygen atom scavenger rather than as a quencher of an excited state of carbon monoxide. However, rate constant data do not support this suggestion and it is concluded that the residual yield of carbon dioxide observed at high dose rates arises from reaction 9[Formula: see text]where CO+ is in an A2Π or B2Σ+ state.

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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