Radiation dosage

One early program carried out at AUied-Signal, Inc. proposed the use of conductive polymers in remotely readable indicators (210). Conductivity changes induced in the conductive polymer could be read externally and the history of the sample known. Systems designed to detect time—temperature, temperature limit, radiation dosage, mechanical abuse, and chemical exposure were developed. 

Torlon-type polymers are unaffected by aliphatic, aromatic, chlorinated and fluorinated hydrocarbons, dilute acids, aldehydes, ketones, ethers and esters. Resistance to alkalis is poor. They have excellent resistance to radiation. If a total of 10 Mrad is absorbed at a radiation dosage of 1 Mrad/h the tensile strength decreases by only 5%. 

Other, non-linear, proposals for the relation between property and radiation dosage include a power law and an exponential relationship ... 

Note that radiation dosage has been used, although this is substituted by time of exposure by many workers. 

The obvious effect of increasing radiation dosages is a decrease in Tg (Table l). The Tg of a control is 40°C higher than the Tg of specimens irradiated to 10,000 Mrads. Also, the o-transition region broadens with increasing dose. 

For the sake of brevity detailed tables of all tests performed are shown for duPont ionomer resins only (Tables II, III, IV, VI to X). The other ethylene copolymers were similarly treated and evaluated. The effects of increasing radiation dosages on certain physical properties of selected duPont ionomers are shown graphically in Figures 1, 2, and 3. 

Sample Designation Radiation Rate, Mrads/sec. Total Radiation Dosage, Mrads... 

Figure 2. Effect of total radiation dosage on ultimate tensile strength...

The relationship between conveyor speed with which a material can be moved under the electron beam and the obtainable radiation dosage, assuming 50% beam absorption efficiency, is shown in Table XII. These data show that a 1.0 specific gravity material could obtain a dosage of... 

The final problem to consider is that owing to attenuation the radiation dosage throughout the sample, and consequently the concentration of contaminants, will not be uniform. A method for doing this is to make dosage measurements throughout the absorber by use of a technique such as has been described by Henley (H13). 

FIGURE 15.23 Percent change in initial tensile shear strength caused by nuclear radiation dosage.7 ... 

The concentration of trapped radicals in the cellulose lattice depended on the radiation dosage and the amount of moisture present in the cellulose during irradiation. The trapped radical yield in irradiated cellulose, containing about 7% moisture, is shown in Table I. If cellulose was irradiated dry (about 0.5% moisture) and in vacuum, an initial yield of 2.5-3 times that shown was obtained however, the concentration of the radicals decreased rapidly on exposure of the irradiated, dry cellulose to moisture (26). 

Rad a unit of radiation dosage corresponding to 10 2 J of energy deposited per kilogram of tissue (from radiation absorbed dose). (21.7)... 

One of the earliest devices for the measurement of radiation dosage, the Fricke dosimeter, is based on the oxidation of the ferrous ion by OH radicals produced in the radiolysis of a dilute aqueous solution of ferrous sulfate ... 

Discuss the interactions of radiation with various kinds of matter and the measurement of radiation dosage (Section 19.4, Problems 33-36). 

Patients receiving radiation therapy may experience complications including severe esophagitis, fatigue, radiation pneumonitis, and cardiac toxicity. These toxicities are usually more common and severe when radiation is combined with chemotherapy. The patient s baseline performance status and the degree of pulmonary dysfunction (e.g., chronic obstructive pulmonary disease from years of tobacco use) must be considered in the decision of radiation dosage and fractionation. 

Since the radiation tolerance for both on and off-site locations was on a 7-day basis, the stack output for the previous 6 days was converted by means of the appropriate templates into radiation-dosage values. A decision could then be made as to whether continuation of reactor operations would result in dosages higher than the specified maximum. 

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