Challenges in dosimetry of particle beams with ultra-high pulse dose rates

JuSPARC, the Jülich Short-Pulsed Particle and Radiation Center, is a laser-driven facility to enable research with short-pulsed photon and particle beams to be performed at the Forschungszentrum Jülich. The conceptual design of JuSPARC is determined by a set of state-of-the-art time-resolved instruments, which are designed to address the electronic, spin, and structural states of matter and their dynamic behaviour. From these instruments and experiments JuSPARC derives the need of operating several dedicated high pulse-power laser systems at highest possible repetition rates. They serve as core units for optimized photon up-conversion techniques generating the light pulses for the respective experiments. The applications also include experiments with spin polarized particle beams, which require the use of laser-based polarized gas targets. Thus, in its rst stage JuSPARC comprises four driving laser systems, called JuSPARC_VEGA, JuSPARC_DENEB, JuSPARC_SIRIUS and JuSPARC_MIRA, which are outlined in this article.

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High pulse dose steroids in Severe COVID-19 pneumonitis refractory hypoxemia to dexamethasone

10.1183/13993003.congress-2021.oa2665 ◽

2021 ◽

Author(s):

Noëlia Khalil ◽

John Kileci ◽

Selene Kock

Keyword(s):

Pulse Dose ◽

Refractory Hypoxemia ◽

High Pulse

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AFFECT OF ULTRASHORT ELECTRON BEAMS ON THE ESCHERICHEA COLI SURVIVAL

International Journal of Advanced Research ◽

10.21474/ijar01/12675 ◽

2021 ◽

Vol 9 (04) ◽

pp. 211-217

Author(s):

G.E. Khachatryan ◽

◽

N.I. Mkrtchyan ◽

S. Sh. Tatikyan ◽

V.B. Arakelyan ◽

...

Keyword(s):

Electron Beams ◽

Ionic Composition ◽

Dose Dependence ◽

Linear Electron ◽

Survival Curves ◽

Particle Beams ◽

Dose Rates ◽

Charged Particle Beams ◽

Electron Bunches ◽

Direct Exposure

The paper represents the study of ultrashort electron beams impact on some Escherichia coliK-12strains with different radiosensitivity. The charged particle beams generated by ultrashort bunch accelerators differ by short duration of particle direct exposure, relatively long intervals between bunches and by high values of instantaneous dose rates. Because of these characteristics, the nature of ultrashort beams impact on biological objects may sufficiently differ from conventional sources of radiation. As a source of ultrashort beams linear electron accellerator AREAL of SichrotronResearcinstitut CANDLE (Yerevan, Armenia) was used. The dependence of E.coli cells survival from electron bunches repetition rate and irradiation media was investigated. It is shown that the dose dependence of the survival degree of microorganisms has a qualitatively different unusual concave shape. Such behavior of the survival curves does not depend on the ionic composition of the irradiation medium as well as on the time of preliminary incubation of microorganisms in this medium. To explain the observed phenomenon, it was assumed that the compensatory capacity of the irradiated object increases with an increase of the irradiation dose.The proposed mathematical model described well the behavior of the survival curves. It is assumed that this change of the compensatory capacity may be determined by oxygen.

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Ovarian Dysfunction in Fetally Irradiated Beagles

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100080717 ◽

1977 ◽

Vol 35 ◽

pp. 658-659

Author(s):

T. M. Seed ◽

M. H. Sanderson ◽

D. L. Gutzeit ◽

T. E. Fritz ◽

D. V. Tolle ◽

...

Keyword(s):

Gamma Rays ◽

Low Dose ◽

Long Term Effects ◽

Ovarian Dysfunction ◽

Dose Rates ◽

Highly Sensitive ◽

Microscopic Evaluation ◽

Ovarian Pathology ◽

Normal Offspring

The developing mammalian fetus is thought to be highly sensitive to ionizing radiation. However, dose, dose-rate relationships are not well established, especially the long term effects of protracted, low-dose exposure. A previous report (1) has indicated that bred beagle bitches exposed to daily doses of 5 to 35 R 60Co gamma rays throughout gestation can produce viable, seemingly normal offspring. Puppies irradiated in utero are distinguishable from controls only by their smaller size, dental abnormalities, and, in adulthood, by their inability to bear young.We report here our preliminary microscopic evaluation of ovarian pathology in young pups continuously irradiated throughout gestation at daily (22 h/day) dose rates of either 0.4, 1.0, 2.5, or 5.0 R/day of gamma rays from an attenuated 60Co source. Pups from non-irradiated bitches served as controls. Experimental animals were evaluated clinically and hematologically (control + 5.0 R/day pups) at regular intervals.

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Electron Beam Damage of Biomolecules Assessed by Energy Loss Spectroscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100069855 ◽

1978 ◽

Vol 36 (3) ◽

pp. 61-69

Author(s):

M. Isaacson ◽

M.L. Collins ◽

M. Listvan

Keyword(s):

Electron Microscopy ◽

Radiation Damage ◽

Structural Integrity ◽

Analytical Electron Microscopy ◽

High Dose ◽

Dose Rates ◽

Special Cases ◽

Analytical Electron ◽

Atom Migration ◽

Beam Damage

Over the past five years it has become evident that radiation damage provides the fundamental limit to the study of blomolecular structure by electron microscopy. In some special cases structural determinations at very low doses can be achieved through superposition techniques to study periodic (Unwin & Henderson, 1975) and nonperiodic (Saxton & Frank, 1977) specimens. In addition, protection methods such as glucose embedding (Unwin & Henderson, 1975) and maintenance of specimen hydration at low temperatures (Taylor & Glaeser, 1976) have also shown promise. Despite these successes, the basic nature of radiation damage in the electron microscope is far from clear. In general we cannot predict exactly how different structures will behave during electron Irradiation at high dose rates. Moreover, with the rapid rise of analytical electron microscopy over the last few years, nvicroscopists are becoming concerned with questions of compositional as well as structural integrity. It is important to measure changes in elemental composition arising from atom migration in or loss from the specimen as a result of electron bombardment.

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Electron-diffraction studies in synthetic polymer materials

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100075579 ◽

1983 ◽

Vol 41 ◽

pp. 362-365

Author(s):

D.T. Grubb

Keyword(s):

Electron Diffraction ◽

Synthetic Polymer ◽

Polymer Materials ◽

Crystallographic Structure ◽

High Dose ◽

Electron Dose ◽

Dose Rates ◽

First Case ◽

Diffraction Patterns ◽

The Many

Diffraction studies in polymeric and other beam sensitive materials may bring to mind the many experiments where diffracted intensity has been used as a measure of the electron dose required to destroy fine structure in the TEM. But this paper is concerned with a range of cases where the diffraction pattern itself contains the important information.In the first case, electron diffraction from paraffins, degraded polyethylene and polyethylene single crystals, all the samples are highly ordered, and their crystallographic structure is well known. The diffraction patterns fade on irradiation and may also change considerably in a-spacing, increasing the unit cell volume on irradiation. The effect is large and continuous far C94H190 paraffin and for PE, while for shorter chains to C 28H58 the change is less, levelling off at high dose, Fig.l. It is also found that the change in a-spacing increases at higher dose rates and at higher irradiation temperatures.

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