A versatile radiochromic dosimeter for low-medium gamma radiation and its application to food irradiation

2017 ◽  
Vol 135 (13) ◽  
pp. 45729 ◽  
Author(s):  
Franceline Aparecida Lopes ◽  
Giovana Ribeiro Ferreira ◽  
Marcella Rocha Franco ◽  
Thiago Schimitberger ◽  
Luiz Oliveira de Faria ◽  
...  
Keyword(s):  
Gamma Radiation ◽  
Food Irradiation ◽  
Radiochromic Dosimeter

Optical evaluation of dithizone solution as a new radiochromic dosimeter

2020 ◽  
Vol 49 (4) ◽  
pp. 249-253 ◽  
Author(s):  
Khalid Rabaeh ◽  
Ahmed Basfar
Keyword(s):  
Free Radicals ◽  
Region Of Interest ◽  
Food Irradiation ◽  
Optical Measurements ◽  
High Dose ◽  
Radiation Processing ◽  
Content Type ◽  
Radiochromic Dosimeter ◽  
Practical Implications ◽  
Dose Radiation

Purpose The purpose of this paper is to propose a new dithizone solution dosimeter for high radiation applications such as polymers applications and food irradiation. Design/methodology/approach Gamma-rays cell of Co-60 source with 8.4 kGy/h dose rate was used to irradiate the dithizone solutions at different irradiation temperatures. The optical measurements of unirradiated and irradiated dithizone dye solution dosimeters were performed using a UV/VIS spectrophotometer at absorption peaks of 421 and 515 nm. Findings The new dosimeter improved significantly with the increase of dithizone dye concentrations from 0.025 to 0.1 mM. The dosimeter shows a perfect pre- and post-irradiation stability after irradiation for five days. Because of irradiation temperature dependence, the dithizone solution dosimeter should be corrected under actual processing conditions. Practical implications Dosimetry is a key point in quality control of radiation processing to assure that uniform and correct radiation doses are delivered to a region of interest. Therefore, this study introduces a dithizone solution dosimeter for high-dose radiation applications such as food irradiation, polymers applications and agriculture. Originality/value Ionizing radiation interacted with the ethanol solvent, resulting in the formation of free radicals, then these free radicals interacted with the dithizone molecule and changed the dye color from yellow to orange.

Mold and Aflatoxin Reduction by Gamma Radiation of Packed Hot Peppers and Their Evolution during Storage

2012 ◽  
Vol 75 (8) ◽  
pp. 1528-1531 ◽  
Author(s):  
QUMER IQBAL ◽  
MUHAMMAD AMJAD ◽  
MUHAMMAD RAFIQUE ASI ◽  
AGUSTIN ARIÑO
Keyword(s):  
Radiation Dose ◽  
Gamma Radiation ◽  
Food Irradiation ◽  
Hot Pepper ◽  
Dependent Relationship ◽  
Hot Peppers ◽  
Polyethylene Bags ◽  
Target Theory ◽  
Gamma Irradiated ◽  
Dose Dependent

The effect of gamma radiation on moisture content, total mold counts, Aspergillus counts, and aflatoxins of three hot pepper hybrids (Sky Red, Maha, and Wonder King) was investigated. Whole dried peppers packed in polyethylene bags were gamma irradiated at 0 (control), 2, 4, and 6 kGy and stored at 25°C for 90 days. Gamma radiation proved to be effective in reducing total mold and Aspergillus counts in a dose-dependent relationship. Total mold counts in irradiated peppers immediately after treatments were significantly lowered compared with those in nonirradiated samples, achieving 90 and 99% reduction at 2- and 4-kGy doses, respectively. Aspergillus counts were significantly reduced, by 93 and 97%, immediately after irradiation at doses of 2 and 4 kGy, respectively. A radiation dose of 6 kGy completely eliminated the population of total molds and Aspergillus fungi. The evolution of total molds in control and irradiated samples indicated no further fungal proliferation during 3 months of storage at 25°C. Aflatoxin levels were slightly affected by radiation doses of 2 and 4 kGy and showed a nonsignificant reduction of 6% at the highest radiation dose of 6 kGy. The distinct effectiveness of gamma radiation in molds and aflatoxins can be explained by the target theory of food irradiation, which states that the likelihood of a microorganism or a molecule being inactivated by gamma rays increases as its size increases.

food was presented by McLaughlin and collaborators (29). Glover’s review (30) is less detailed but more recent. Dosimetry for food irradiation processing has reached a high level of perfec­ tion. Many standards for this purpose have been issued by the American Society for Testing and Materials (31,32). The role of dosimetry in good radiation processing practice is described in the Recommended International Code of Practice for the Operation of Irradiation Facilities Used for the Treatment of Foods (see Appendix II) and in a series of Codes of Good Irradiation Practice issued by ICGFI (International Consultative Group on Food Irradiation) (see Appendix III). With some food items, such as whole eggs (33) and ground com (34), it may be possible to use the food itself as a dose meter. This will be discussed in more detail in Chapter 5. As mentioned earlier, electron beams, on the one hand, and gamma rays and x-rays, on the other hand, differ greatly in their ability to penetrate matter. This has important consequences for the dose distribution in the irradiated medium. Since many foods consist mostly of water, the penetration of radiation in water is shown in Figure 14. When an electron beam penetrates an aqueous medium the dose somewhat below the surface is higher than at the surface. This is due to the formation of secondary electrons which, because of their lower energy, are more effectively absorbed than the primary electrons. Also, scattering causes some secondary electrons to escape from the surface in the direction opposite to that of the beam of primary electrons. Thus a 10-MeV electron beam giving a dose of 10 kGy at the surface will deposit about 12.5 kGy at 2 cm below the surface. As more and more primary electrons lose their energy by interacting with water molecules, the absorbed dose decreases with increasing depth and at about 5 cm the limit of penetration is reached. In contrast, the dose delivered by gamma rays decreases continuously. The rate of decrease is faster with 137Cs gamma radiation than with 60Co gamma radiation. With x-rays it depends on the energy of the x-ray-producing electrons. For practical purposes the penetration of 5-MeV x-rays is comparable to that of 60Co gamma rays. Two-sided irradiation permits processing of thicker packages with more uni­ form dose distribution, as indicated in Figure 15. If the density of the irradiated medium is less than that of water, e.g., in fatty foods or in dehydrated or porous foods, the depth of penetration is correspondingly greater. The 10-MeV electron beam, which barely reaches a depth of 5 cm in water, will reach approximately 10 cm at a density of 0.5g/cm3. From Figures 14 and 15 it is clear that an absolutely uniform dose distribution cannot be obtained, even if a material of uniform density is irradiated. If dose

1995 ◽  
pp. 52-52
Keyword(s):  
Electron Beam ◽  
Gamma Radiation ◽  
Gamma Rays ◽  
Dose Distribution ◽  
Food Irradiation ◽  
X Rays ◽  
Secondary Electrons ◽  
60Co Gamma ◽  
American Society ◽  
Primary Electrons

As mentioned in the previous chapter, many experiments on food irradiation in the 1950s were carried out with spent-fuel rods from nuclear reactors. Such fuel rods contain a mixture of many fission products, with greatly differing half-lives, emitting different types of radiation with different energies. The composition of fuel rods changes all the time because the radionuclides with short half-lives disappear quickly, whereas those with longer half-lives remain. Although fuel rods are primarily a source of gamma radiation (the less penetrating alpha and beta radiation are absorbed by the steel hull of the rods) they do give off some neutrons. Since the latter can produce radioactivity when they interact with matter such as food, fuel rods have not been used for irraditation of foods since the early 1960s. Because of their constantly varying composition, fuel rods also make dosimetry difficult, and this was another reason for abandoning their use. Individual constituents of spent fuel rods can be separated in reprocessing plants by chemical methods. One of the radionuclides obtainable in this way is Cs. With a half-life of 30 years and emission of gamma radiation (0.66 MeV) and beta radiation (0.51 MeV and 1.18 MeV), '^C s decays to stable '^B a (barium). After the ,37Cs is separated from the other constituents of the fission waste in the form of CsCl it is triply encapsulated in stainless steel containers because CsCl is soluble in water. If it leaked out it could cause contamination of the environment. As provided by the Waste Encapsulation and Storage Facility (WESF) at Hanford, Washington, the 137Cs capsule is 400 mm in active length (500 mm in total length) and 67 mm in diameter. There are only a few reprocessing plants in the world and the capacity for extracting ,37Cs from spent fuel rods is very limited. Plans for building several commercial reprocessing facilities in the United States were canceled by Presi­ dent Carter’s 1977 decision that the United States would not engage in commer­ cial reprocessing of spent nuclear fuel. As a consequence, not much ,37Cs is available and there are not many gamma radiation facilities which use ,Cs. No

1995 ◽  
pp. 31-31
Keyword(s):  
United States ◽  
Gamma Radiation ◽  
Spent Nuclear Fuel ◽  
Fission Products ◽  
The United States ◽  
Food Irradiation ◽  
Beta Radiation ◽  
Spent Fuel ◽  
Fuel Rods ◽  
Active Length

scholarly journals Effect of Temperature and Gamma Radiation on Salmonella Hadar Biofilm Production on Different Food Contact Surfaces

2018 ◽  
Vol 2018 ◽  
pp. 1-6
Author(s):  
Najla Ben Miloud Yahia ◽  
Salma Kloula Ben Ghorbal ◽  
Lobna Maalej ◽  
Abdelwaheb Chatti ◽  
Alya Elmay ◽  
...  
Keyword(s):  
Gamma Radiation ◽  
Biofilm Formation ◽  
Radiation Treatment ◽  
Food Irradiation ◽  
Effect Of Temperature ◽  
Food Contact ◽  
Biofilm Production ◽  
Food Contact Surfaces ◽  
Salmonella Hadar ◽  
Contact Surfaces

Salmonella is a pathogen transmitted by foods and it is one of the most important target bacteria in food irradiation studies. Few works were carried out on the effectiveness of gamma radiation against biofilms formed by this bacterium. Salmonella can form a biofilm on different material surfaces. The physicochemical properties of surfaces and environmental factors influence the adhesion of this pathogen. The present study investigated the effect of gamma radiation (1 and 2 kGy) and temperature (28°C and 37°C) on the development of Salmonella Hadar biofilm on polyvinyl chloride (PVC), glass, cellophane paper (CELLO), and polystyrene (POLY). The obtained results indicated that biofilm production is surface and temperature dependent. In addition, biofilm formation decreased significantly after gamma irradiation at either 1 or 2 kGy doses. However, the agfD and adrA genes expression did not demonstrate significant decrease. This work highlighted that gamma radiation treatment could reduce the biofilm formation of Salmonella enterica serovar Hadar on different food contact surfaces.

Effects of sterilization modes on the mechanical strengths of plaster of paris implants

1989 ◽  
Vol 47 ◽  
pp. 890-891
Author(s):  
K. Cowden ◽  
B. Giammara ◽  
T. Devine ◽  
J. Hanker
Keyword(s):  
Gamma Radiation ◽  
Calcium Sulfate ◽  
Significant Loss ◽  
Potassium Sulfate ◽  
Limiting Factors ◽  
Radiation Sterilization ◽  
Plaster Of Paris ◽  
Hardness Tester ◽  
Dry Heat ◽  
Calcium Sulfate Hemihydrate

Plaster of Paris (calcium sulfate hemihydrate, CaSO4. ½ H2O) has been used as a biomedical implant material since 1892. One of the primary limiting factors of these implants is their mechanical properties. These materials have low compressive and tensile strengths when compared to normal bone. These are important limiting factors where large biomechanical forces exist. Previous work has suggested that sterilization techniques could affect the implant’s strength. A study of plaster of Paris implant mechanical and physical properties to find optimum sterilization techniques therefore, could lead to a significant increase in their application and promise for future use as hard tissue prosthetic materials.USG Medical Grade Calcium Sulfate Hemihydrate Types A, A-1 and B, were sterilized by dry heat and by gamma radiation. Types A and B were additionally sterilized with and without the setting agent potassium sulfate (K2SO4). The plaster mixtures were then moistened with a minimum amount of water and formed into disks (.339 in. diameter x .053 in. deep) in polyethylene molds with a microspatula. After drying, the disks were fractured with a Stokes Hardness Tester. The compressive strengths of the disks were obtained directly from the hardness tester. Values for the maximum tensile strengths σo were then calculated: where (P = applied compression, D = disk diameter, and t = disk thickness). Plaster disks (types A and B) that contained no setting agent showed a significant loss in strength with either dry heat or gamma radiation sterilization. Those that contained potassium sulfate (K2SO4) did not show a significant loss in strength with either sterilization technique. In all comparisons (with and without K2SO4 and with either dry heat or gamma radiation sterilization) the type B plaster had higher compressive and tensile strengths than that of the type A plaster. The type A-1 plaster however, which is specially modified for accelerated setting, was comparable to that of type B with K2SO4 in both compressive and tensile strength (Table 1).

Use of the comet assay to measure DNA damage in cells exposed to photosensitizers and gamma radiation

1999 ◽  
Vol 96 (1) ◽  
pp. 143-146 ◽  
Author(s):  
J.-P. Pouget ◽  
J.-L. Ravanat ◽  
T. Douki ◽  
M.-J. Richard ◽  
J. Cadet
Keyword(s):  
Dna Damage ◽  
Comet Assay ◽  
Gamma Radiation ◽  
In Cells

National primary standard of air kerma, air kerma rate, exposure, exposure rate and energy flux for X-rays and gamma radiation GET 8-2019

2020 ◽  
pp. 8-12
Author(s):  
Alexandr V. Oborin ◽  
Anna Y. Villevalde ◽  
Sergey G. Trofimchuk
Keyword(s):  
Gamma Radiation ◽  
Energy Flux ◽  
Primary Standard ◽  
Average Energy ◽  
Ion Pair ◽  
X Rays ◽  
Exposure Rate ◽  
Ionization Chambers ◽  
Air Kerma ◽  
Air Kerma Rate

The results of development of the national primary standard of air kerma, air kerma rate, exposure, exposure rate and energy flux for X-rays and gamma radiation GET 8-2011 in 2019 are presented according to the recommendations of the ICRU Report No. 90 “Key Data for Ionizing-Radiation Dosimetry: Measurement Standards and Applications”. The following changes are made to the equations for the units determination with the standard: in the field of X-rays, new correction coefficients of the free-air ionization chambers are introduced and the relative standard uncertainty of the average energy to create an ion pair in air is changed; in the field of gamma radiation, the product of the average energy to create an ion pair in air and the electron stopping-power graphite to air ratio for the cavity ionization chambers is changed. More accurate values of the units reproduced by GET 8-2019 are obtained and new metrological characteristics of the standard are stated.

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