Health Physics Instruments: What Are the Current Needs?

Effect of radiation and thermal treatment on structural and transport parameters for cellulose regenerated membranes

Dislocation patterning driven by interactions of dislocations with deformation-induced point defects is considered. The effect of concurrent irradiation-induced production of point defects is also included. The uniform time-dependent solution of the set of equations describing the evolution of the system is “probed” by small periodic perturbations. A linear stability condition obtained in this way as well as the preferred wavelength of the emerging pattern depend on the values of the parameters reflecting biases in the production and annihilation of vacancies and interstitial atoms. It is proposed that by studying the effect of different types of radiation and different irradiation intensities on the occurrence and the wavelength of the dislocation pattern information about the deformation-induced point defect production bias may be obtained.

Problem-Based Learning Curriculum as a Tool to Increase Medical Student Exposure to Radiation Oncology

The paper discusses the nature and consequences of competition between different types of radiation - spontaneous and induced, as well as superradiation in quantum and classical systems. Near the new threshold for the generation of stimulated radiation, t

Thermoluminescence Analysis for Detection of Irradiated Food—Luminescence Characteristics of Minerals for Different Types of Radiation and Radiation Doses

<p indent="0mm">Ultra-high dose rate radiotherapy (FLASH-RT) has emerged as a hot topic in the field of radiotherapy in recent years. A series of experimental data indicate that FLASH-RT can effectively kill tumors while significantly spare normal tissues from radiation damage. This unique phenomenon is known as the FLASH effect. Whether the FLASH effect is triggered or not is influenced by various factors, including physical parameters and biochemical parameters. Physical parameters include dose rate, total dose, dose fractionation strategy, and beam structure, whereas biochemical parameters include tissue oxygenation level, tissue type, and biological endpoint. Adjusting these parameters can have differing degrees of impact on tissue responses to FLASH-RT. For instance, experimental data indicate that, compared to conventional radiation therapy (CONV-RT), FLASH-RT with an average dose rate exceeding <sc>100 Gy/s</sc> can completely protect mice’s cognitive function. However, this protective effect diminishes as the dose rate decreases and disappears when the dose rate falls below <sc>30 Gy/s.</sc> A review of published data suggests that the degree of reduction in normal tissue toxicity by FLASH-RT is influenced by the dose in a single fraction. Higher single doses result in greater reductions in toxicity, but excessively high doses can trigger severe late-stage adverse effects, which warrant caution. For beam structure and radiation type, the types of radiation currently used in preclinical FLASH-RT research include low-energy electrons, very high energy electrons (VHEE), low-energy X-rays, high-energy X-rays, protons, and heavy ions. Overall, the biological effects of FLASH-RT produced by different types of radiation are similar and consistent. However, the technical routes used to generate FLASH-RT beams reported in the literature vary widely, and the beam structures used in different studies differ significantly. It is necessary to clearly describe the detailed beam structure information used in experiments, including dose, dose rate, irradiation time, pulse repetition frequency, pulse width, and single pulse dose. Regarding biochemical factors, oxygen concentration is one of the key factors affecting radiobiological effects. The biological effects of FLASH-RT are also regulated by oxygen content, but it is worth investigating the differential responses of normal and tumor tissues to changes in oxygen content induced by FLASH-RT. The radiation sensitivity of different tissues and organs varies, leading to differences in the benefits gained from FLASH-RT. Additionally, the choice of study endpoints significantly impacts the conclusions of preclinical research on the biological effects of FLASH-RT. For instance, using different markers of DNA damage or analyzing acute versus late-phase indicators post-radiotherapy may yield different conclusions. This study will systematically analyze the effects of physical and biochemical parameters on the FLASH effect based on published experimental data, and the findings will provide useful suggestions for further research on FLASH biological effects.

This introductory chapter gives a description of the different types of radiation and briefly outlines the means of their production. Spectral distributions are explained and discussed. A final paragraph deals with the fundamentals of radioactivity.

In support of the Department of Energy/Office of Technology Development`s Expedited Site Characterization (ESC) project (coordinated by Ames Laboratory), the Pacific Northwest Laboratory demonstrated two complementary technologies at the St. Louis Airport (SLAP) site that have been designed and optimized for the rapid, in situ quantification of radionuclide contamination in surface soils. The sensors are optimized for the detection of high-energy beta particles or gamma rays emitted from the decay of specific radionuclides of interest. These technologies were demonstrated by measuring the beta and gamma fluxes at several locations within the SLAP site. Measurements were converted to average contamination levels, using detector calibrations performed with spiked samples (beta) or sealed sources (gamma). Additionally, subsurface activity levels were derived from discrete soil samples (provided by the ESC field crew) via gamma-ray spectrometry in a controlled laboratory setting. Since the beta and gamma sensor technologies are intrinsically sensitive to different types of radiation and activity distributions (i.e., surface and shallow subsurface, respectively), the data obtained from the two detectors provide complementary information about the distribution of the contamination. The results reported here suggest that a number of locations within the SLAP site have elevated levels of {sup 211}U, and the differences between the beta and gamma activities indicate that the contamination is largely located near the surface of the soil.

In this paper, the radiation induced air fluorescence is investigated for several different types of radiation sources, including high brightness laser sources, X-ray radiation sources, and alpha radiation sources. First, the air fluorescence spectrum with three spectral bandpass filters induced by the high intensity laser was analyzed from spectrometer detector. Second, the air fluorescence intensity induced by different types of radiation are measured from photomultiplier tube detector and followed by discussion. Finally, the potential application of radiation induced air fluorescence for the radiation detection is addressed.

In the upcoming years, agriculture will have a central role not only in feeding a growing population worldwide, but also in Space-related research, through the implementation of protected cultivation systems. To make it possible, it is fundamental to understand plants&amp;#8217; ability to cope with a dynamic environment, made worst by harsh Space conditions including microgravity and ionizing radiation.Plant plasticity in adaptation relies on the development of both structural and physiological traits, which are deeply influenced by the environment; therefore, leaf morpho-anatomical traits are critical for balancing plant water and CO2&amp;#160;exchange and determine the efficiency of CO2&amp;#160;diffusion within the mesophyll. Their relationship has been widely studied; however, it remains unclear at what extent leaf anatomical traits may drive leaf hydraulic and photosynthetic acclimation to Space environmental stressors.Previous studies have proven that ionizing radiation can induce positive, null or negative effects depending on the radiation type, dose and exposure (acute or chronic) as well as plant developmental stage and species.In this study, we compared functional, anatomical (e.g., leaf area, leaf dry matter content, leaf mass per area, stomatal and vein size and density, mesophyll organization, chloroplast distribution) and biochemical traits (e.g. chlorophyll and carotenoids content, polyphenols, ascorbic acid) of brassica microgreens (Brassica rapa L. subsp. sylvestris var. esculenta) exposed to three different types of radiation (X-rays, Carbon ion 12C, Iron ion 56Fe) at the same doses (0-control, 0.3, 1, 10, 20, and 25 Gy). Irradiation took place at the GSI Helmholtzzentrum f&amp;#252;r Schwerionenforschung GmbH, and then microgreens were cultivated in a growth chamber under controlled condition. Microgreens were chosen as study model for two main reasons. First, microgreens are good candidates for the diet integration of astronauts because they are rich in nutraceutical compounds and can be cultivated directly in Space with very low input resources. From a fundamental science viewpoint, understanding the morpho-functional responses of microgreens is needed because at this stage of development plants are very vulnerable: overcoming the microgreens stage may represent a bottleneck in the cultivation of adult plants in bioregenerative life support systems.The results suggest the different radiation type and doses determined alterations in morpo-anatomical and biochemical traits which may determine the limits of crop responses and biomass production. These findings should be considered when studying plant adaptation to Space environment, trying to optimize plant growth in controlled environment to achieve the sustainability of the system.&amp;#160;Part of the results presented here is based on the experiment Bio_08_DeMicco, which was performed at the SIS18 at the GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany) in the frame of FAIR Phase-0.&amp;#160;

Nowadays, radiation technologies are widely used in industry, medicine and other fields. One of the particular cases of application of such technologies is the irradiation-induced coloring of topaz. As a result of the application of this technology, colorless topaz acquires a more noble, respectively, economically advantageous color. For this, different types of radiation can be used. In the case of irradiation-induced coloring of topaz using neutrons, it is necessary to formation optimal conditions for irradiation of topaz. First of all, in the topaz irradiation zone it is necessary to formation a "hard" neutron spectrum not only for the formation of color centers, but also to reduce the residual radioactivity in the topaz. In this work, the possibility of implementing the technology of irradiation-induced coloring of topaz in the WWR-K research reactor was evaluated. For this, the energy distribution of neutrons in the central and peripheral irradiation positions of the WWR-K reactor was determined. On the basis of the obtained values, the time to reach the target neutron fluence (1018 cm-2) was estimated. The influence of the ratio of the flux of fast to thermal neutrons on the activation of natural impurities in topaz is shown. The results of trial irradiation of topazes in the WWR-K reactor without formation special conditions are presented. Ways to optimize the conditions for irradiation of topazes in the WWR-K reactor in order to improve the economic efficiency of the work were proposed.

The relative biological effectiveness (RBE) of tritiated water (HTO) was investigated using mouse immature oocytes. Juvenile mice, having immature oocytes that are highly sensitive to radiation killing, were exposed to HTO, 137Cs gamma rays, 60Co gamma rays, or 252Cf fission neutrons. The 137Cs gamma rays were used to simulate the changing dose rate (but not the radiation quality) received from HTO (see section 2). On the 14th day after birth, female ICR strain mice were injected once in the abdominal cavity with HTO at levels of 1.70, 3.40, 6.81, or 10.21 MBq/10g body weight, and their ovaries were removed 2 weeks after the injection. (The cumulative doses are equivalent to 0.039, 0.077, 0.159 and 0.246 Gy, respectively.) The survival rate of oocytes was determined by light microscopy inspection of serial sections, and the results of the different exposures were compared. The number of surviving oocytes decreased exponentially with increasing dose of HTO or 137Cs, and RBEs of HTO compared to 137Cs gamma rays ranged from 1.1 to 3.5. The relative effectiveness of the different types of radiations was compared, and the results of the comparison, in order of increasing effectiveness, was 137Cs, 60Co, HTO, and 252Cf. The RBE of 252Cf compared to 60Co gamma rays ranged from 1.6 to 3.5.

Mossbauer spectroscopy can be performed in transmission and backscattering geometry. The backscattered conversion electrons and X-rays can be used for nondestructive phase analysis on surfaces. Based on their different interactions in materials, they enable analyses of different depths. It is of particular interest to measure backscattering radiation and γ-ray transmission simultaneously. Based on the hyperfine parameters of the Mossbauer spectra information about phases, structures, defects and magnetic properties can be obtained. Besides the qualitative analysis in general an accurate quantitative phase analysis is possible. For example spectra of laser treated alloys are shown. It is the purpose of this note to demonstrate the use of these different types of radiation (electrons, X-ray and γ-ray) in analyzing surface phenomena.

High-energy electron, proton, neutron, photon and ion irradiation of semiconductor diodes and solar cells has long been a topic of considerable interest in the field of semiconductor device fabrication. The inevitable damage production during the process of irradiation is used to study and engineer the defects in semiconductors. In a strong radiation environment in space, the electrical performance of solar cells is degraded due to direct exposure to energetically charged particles. A considerable amount of work has been reported on the study of radiation damage in various solar cell materials and devices in the recent past. In most cases, high-energy heavy ions damage the material by producing a large amount of extended defects, but high-energy light ions are suitable for producing and modifying the intrinsic point defects. The defects can play a variety of electronically active roles that affect the electrical, structural and optical properties of a semiconductor. This review article aims to present an overview of the advancement of research in the modification of glassy semiconducting thin films using different types of radiations (light, proton and swift heavy ions). The work which has been done in our laboratory related to irradiation induced effects in semiconducting thin films will also be compared with the existing literature.

Background/Objectives: Within the range of spread-out Bragg peak (SOBP), LET (linear energy transfer) gradually increases from proton beam entrance point toward the beam exit direction. While it is expected that the change in LET would lead to correspondent change in RBE (relative biological effectiveness) on many human cell lines, the incomplete cell killing due to low LET can result in tumor recurrence. Hence, this study aimed to assess the RBE on different cancer cell lines along low-LET proton SOBP. Methods: The clonogenicity of A549 and Panc-1 cells after irradiation was evaluated for investigating cell radiosensitivity in response to different types of radiation. The isoeffect doses of 6-MV photon and low-LET proton beams that resulted in equivalent cell surviving fractions at proton dose of 2 or 4 Gy were compared. Results: Ratios of α/β of A549 and Panc-1 cells from photon irradiation are 51.69 and −0.7747, respectively; RBE (2 Gy proton SOBP) on A549 and Panc-1 cells are 0.7403 ± 0.3324 and 1.0986 ± 0.3984, respectively. In addition, the change in RBE with proton LET was in a cell-specific and dose-dependent manner (LET-RBE linear correlations: A549 cells [r = 0.4673, p = 0.2430] vs. Panc-1 cells at 4 Gy [r = 0.7085, p = 0.0492]; Panc-1 cells at 2 Gy [r = −0.4123, p = 0.3100] vs. 4 Gy [r = 0.7085, p = 0.0492]). Conclusions: Compared with A549 cells, Panc-1 cells present greater resistance to low-LET proton beams. In addition, currently employed generic RBE value at 1.1 for proton therapy neglected the variation in cell-/tumor-specific radiobiological responses toward different dose levels of proton beams.