Technical and regulatory requirements for radiation sterilization facilities using electron beam accelerators

Author(s):  
M.C. Saylor ◽  
L.A. Parks ◽  
C.H. Herring
2021 ◽  
Vol 11 (2) ◽  
pp. 217-223
Author(s):  
Davison Baldos ◽  
◽  
Joseph Puno ◽  
Levelyn Tolentino ◽  
Djowel Montefalcon ◽  
...  

This study was conducted to determine the effect of radiation sterilization on alginate wound dressing containing honey from the Philippine stingless bee, Tetragonula biroi. Our results show that a radiation dose of 30 kGy did not affect the antibacterial property of honey against Staphylococcus aureus. Electron-beam irradiation did not produce significant alterations in the physicochemical properties (pH, total soluble solids, and flavonoids); however, the total phenolics was significantly increased in honey with higher irradiation doses. Demonstrating that irradiation can be applied to honey with negligible physicochemical effects, honey was incorporated in alginate and exposed to a sterilization dose of 25 kGy using an electron beam facility. Irradiation did not affect the physicochemical properties (pH, moisture content, gel fraction, moisture vapor transmission rate (MVTR), and fluid handling capacity) of the honey alginate wound dressing (HAWD). The perspectives for the potential use of irradiated HAWD as a natural product-based substitute for commercial wound care products may be considered.


2015 ◽  
Vol 1094 ◽  
pp. 11-14
Author(s):  
Xing Fang Li ◽  
Song Yi Lin ◽  
Zuo Zhao Wang

Electron beam irradiation is a chemical technology which mainly applies to food irradiation preservation, radiation sterilization of medical supplies, radiation chemistry and so on. It can change the molecular structure by using the radioactive radiation. In this present study, soybean protein concentrate powder was treated by electron beam irradiation to investigate its effects on the DH, the peptide antioxidant activity and the microcosmic surface morphology. The results indicated that the electron beam irradiation did not have effect on the DH. However, the peptide antioxidant activity significantly increased when increasing the irradiation dose. The highest peptide antioxidant activity 56.84 % was obtained at 3.24 kGy. Scanning electron microscope (SEM) revealed that there were a number of changes to the microcosmic surface morphology after the electron beam irradiation. Not only the shape of the soybean protein concentrate powder particles was changed, but the surface state was changed as well.


2010 ◽  
Vol 68 (9) ◽  
pp. 1627-1635 ◽  
Author(s):  
Babita K. Singh ◽  
Dilip V. Parwate ◽  
Indrani B. Dassarma ◽  
Sudhir K. Shukla

Vacuum ◽  
2001 ◽  
Vol 62 (2-3) ◽  
pp. 225-231 ◽  
Author(s):  
A.S Ivanov ◽  
V.P Ovchinnikov ◽  
M.P Svinin ◽  
N.G Tolstun ◽  
S.L Bogart

Author(s):  
G. G. Shaw

The morphology and composition of the fiber-matrix interface can best be studied by transmission electron microscopy and electron diffraction. For some composites satisfactory samples can be prepared by electropolishing. For others such as aluminum alloy-boron composites ion erosion is necessary.When one wishes to examine a specimen with the electron beam perpendicular to the fiber, preparation is as follows: A 1/8 in. disk is cut from the sample with a cylindrical tool by spark machining. Thin slices, 5 mils thick, containing one row of fibers, are then, spark-machined from the disk. After spark machining, the slice is carefully polished with diamond paste until the row of fibers is exposed on each side, as shown in Figure 1.In the case where examination is desired with the electron beam parallel to the fiber, preparation is as follows: Experimental composites are usually 50 mils or less in thickness so an auxiliary holder is necessary during ion milling and for easy transfer to the electron microscope. This holder is pure aluminum sheet, 3 mils thick.


Author(s):  
Kenneth H. Downing ◽  
Robert M. Glaeser

The structural damage of molecules irradiated by electrons is generally considered to occur in two steps. The direct result of inelastic scattering events is the disruption of covalent bonds. Following changes in bond structure, movement of the constituent atoms produces permanent distortions of the molecules. Since at least the second step should show a strong temperature dependence, it was to be expected that cooling a specimen should extend its lifetime in the electron beam. This result has been found in a large number of experiments, but the degree to which cooling the specimen enhances its resistance to radiation damage has been found to vary widely with specimen types.


Author(s):  
L. D. Jackel

Most production electron beam lithography systems can pattern minimum features a few tenths of a micron across. Linewidth in these systems is usually limited by the quality of the exposing beam and by electron scattering in the resist and substrate. By using a smaller spot along with exposure techniques that minimize scattering and its effects, laboratory e-beam lithography systems can now make features hundredths of a micron wide on standard substrate material. This talk will outline sane of these high- resolution e-beam lithography techniques.We first consider parameters of the exposure process that limit resolution in organic resists. For concreteness suppose that we have a “positive” resist in which exposing electrons break bonds in the resist molecules thus increasing the exposed resist's solubility in a developer. Ihe attainable resolution is obviously limited by the overall width of the exposing beam, but the spatial distribution of the beam intensity, the beam “profile” , also contributes to the resolution. Depending on the local electron dose, more or less resist bonds are broken resulting in slower or faster dissolution in the developer.


Author(s):  
Joseph J. Comer

Domains visible by transmission electron microscopy, believed to be Dauphiné inversion twins, were found in some specimens of synthetic quartz heated to 680°C and cooled to room temperature. With the electron beam close to parallel to the [0001] direction the domain boundaries appeared as straight lines normal to <100> and <410> or <510> directions. In the selected area diffraction mode, a shift of the Kikuchi lines was observed when the electron beam was made to traverse the specimen across a boundary. This shift indicates a change in orientation which accounts for the visibility of the domain by diffraction contrast when the specimen is tilted. Upon exposure to a 100 KV electron beam with a flux of 5x 1018 electrons/cm2sec the boundaries are rapidly decorated by radiation damage centers appearing as black spots. Similar crystallographio boundaries were sometimes found in unannealed (0001) quartz damaged by electrons.


Author(s):  
D. E. Speliotis

The interaction of electron beams with a large variety of materials for information storage has been the subject of numerous proposals and studies in the recent literature. The materials range from photographic to thermoplastic and magnetic, and the interactions with the electron beam for writing and reading the information utilize the energy, or the current, or even the magnetic field associated with the electron beam.


Author(s):  
P.J. Killingworth ◽  
M. Warren

Ultimate resolution in the scanning electron microscope is determined not only by the diameter of the incident electron beam, but by interaction of that beam with the specimen material. Generally, while minimum beam diameter diminishes with increasing voltage, due to the reduced effect of aberration component and magnetic interference, the excited volume within the sample increases with electron energy. Thus, for any given material and imaging signal, there is an optimum volt age to achieve best resolution.In the case of organic materials, which are in general of low density and electric ally non-conducting; and may in addition be susceptible to radiation and heat damage, the selection of correct operating parameters is extremely critical and is achiev ed by interative adjustment.


Sign in / Sign up

Export Citation Format

Share Document