Ionizing radiation measurement

Ionizing radiation measuring instruments containing, for purposes of internal calibration or standardization, one or more sources of byproduct material—exempt quantities of 241 Am 0.05 pCi NRC 2001 g 10CFR30.15(a)(9)... 

ISO, Determination of the detection limit and decision threshold for ionizing radiation measurements Part 3, ISO. 2000, ISO 11929-3 2000. 

First, aerosol particles are important from the point of view of atmospheric electricity. A fraction of the air molecules is electrically charged (small ions), as a result of ionizing radiation. Measurements show (Bricard and Pradel, 1966) that in 1 cm3 of surface air about 10 ion-pairs are formed each second. Eight out of ten are produced by the radioactivity of the air and soil, while the other two are produced by cosmic radiation. The electrical properties of the air are determined by the electrical mobility (B) of ions formed ... 

Polyphenylene sulfide is resistant to ionizing radiation. Measurements on molded parts made from glass fiber-reinforced polyphenylene sulfide have shown that neither flexural strength nor Young s modulus change under y- (50,000 kGy) or neutron radiation (10,000 kGy) [572]. Polyphenylene sulfide can be repeatedly sterilized. 

Source Counsel of Ionizing Radiation Measurements Workshop on Standards, Intercomparisons, and Performance Evaluations for Low-Level and Environmental Radionuclide Mass Spectrometry— Meeting Proceedings, NIST, Gaithersburg, MD, April 1999. 

If monochromatic X-rays are used as the ionizing radiation the experimental technique is very similar to that for XPS (Section 8.1.1) except that it is the kinetic energy of the Auger electrons which is to be measured. Alternatively, a monochromatic electron beam may be used to eject an electron. The energy E of an electron in such a beam is given by... 

U.S. radiation protection guidelines are estabHshed by the National CouncH on Radiation Protection and Measurement (NCRP) and are based on the recommendations of the International Commission on Radiological Protection (ICRP). The National Research CouncH also sponsors a report from its advisory committee on the biological effects of ionizing radiations (20). 

Conduct a risk assessment to any employee and other persons to identify measures needed to restrict exposure to ionizing radiation and to assess magnitude of risk including identifiable accidents. 

From the National Council on Radiation Protection and Measurements, "Recommendations on Limits for Exposure to Ionizing Radiation," NCRP report No. 91, 7910 Woodmont Ave., Bethesda, MD, June 1987. 

Ionizing radiation is unselective and has its effect on the monomer, the polymer, the solvent, and any other substances present in the system. The radiation sensitivity of a substrate is measured in terms of its G value or free radical yield G(R). Since radiation-induced grafting proceeds by generation of free radicals on the polymer as well as on the monomer, the highest graft yield is obtained when the free radical yield for the polymer is much greater than that for the monomer. Hence, the free radical yield plays an important role in grafting process [85]. 

The Control of Substances Hazardous to Health (COSHH) Regulations 1989 covers virtually all substances hazardous to health. Only asbestos, lead, materials producing ionizing radiation and substances below ground in mines (which all have their own legislation) are excluded. The Regulations set out measures that employers must implement. Failure to comply with COSHH, in addition to exposing employees and others to risk, constitutes an offence and is subject to penalties under the Health and Safety at Work Act, etc. 1974. 

One problem that should be of particular interest for separation processes is the identification and kinetic characterization of the reactive radicals that occur when strong nitric acid solutions are subject to ionizing radiation. The important reducing radical in such solutions is the H atom. There are presently no direct measurements of the rate of reduction of H atoms with any Pu oxidation state. 

Electron spin resonance (ESR) measures the trapped electron population in a lattice, which is directly related to the amount of ionizing radiation received by the sample since its formation. The total radiation dose received by the sample is estimated from the ESR... 

Epidemiological and Human Dosimetry Studies. Epidemiological studies of radiation dose typically involve estimates of exposure that are based on whole-body measurements of internally-deposited americium. A need remains for epidemiological data that can provide quantitative human dose-response information while supplying additional information on the health effects of exposure to ionizing radiation and americium in particular, for cases of known internal exposure. 

Total Ionization—The total electric charge of one sign on the ions produced by radiation in the process of losing its kinetic energy. For a given gas, the total ionization is closely proportional to the initial ionization and is nearly independent of the nature of the ionizing radiation. It is frequently used as a measure of absorption of radiation energy. 

It has been reported for many years that condensation nuclei can be produced by ionizing radiation. Recent studies have improved the measurement of the activity size distribution of these ultrafine particles produced by radon and its daughters (Reineking, et al., 1985 Knutson, et al., 1985). It seems that the Po-218 ion is formed by the radon decay, is neutralized within a few tens of milliseconds, and then attached to an ultrafine particle formed by the radiolysis generated by the polonium ion recoil. Although there will be radiolysis along the alpha track, those reactions will be very far away (several centimeters) from the polonium nucleus when it reaches thermal velocity. The recoil path radiolysis therefore seems to be the more likely source of the ultrafine particles near enough to the polonium atom to rapidly incorporate it. 

About 1910, M. Curie suggested that ions were responsible for the chemical effects of radioactive radiations. Soon thereafter, mainly due to the pioneering work of Lind on gases, the notation M/N was introduced for a quantitative measure of the radiation effect, where N is the number of ion pairs formed and M is the number of molecules transformed—either created or destroyed. This notation, referred to as the ion pair yield, was most conveniently employed in gases where N is a measurable quantity. However, for some time the same usage was extended to condensed systems assuming that ionization did not depend on the phase. This, however, is not necessarily correct. The notation G was introduced by Burton (1947) and others to denote the number of species produced or destroyed per 100 eV absorption of ionizing radiation. In this sense, it is defined... 

The gold-leaf electroscope has been widely used in the past to study ionizing radiation. The first measurement of the properties of ionizing radiation was accomplished with this instrument. A microscope containing a graduated scale in the eyepiece is used to observe the gold leaf. 

Because weak CL emission often is produced from the oxidation of many solid organic compounds, the measurement of this light emission may be used as an indicator of changes in materials composition due to oxidation processes, and for evaluating stabilizers intended to prevent or retard these oxidative alterations [6], Some examples of materials than can be characterized by CL emission are the polymers that are degraded by weathering, exposure to heat, or exposure to ionizing radiation, or food components that suffer flavor alterations. In this... 

Numerous behavioral measures have been evaluated for their usefulness in providing a sensitive index of exposure to ionizing radiation. Radiation-related mental retardation is the most likely type of behavioral abnormality in humans sensitivity peaked between 8 and 15 weeks of conception... 

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