Radiation, ionizing dose ranges

Alanine dosimeters are based on the ability of 1-a alanine (a crystalline amino acid) to form a very stable free radical when subjected to ionizing radiation. The alanine free radical yields an electron paramagnetic resonance (EPR) signal that is dose dependent, yet independent of the dose rate, energy type, and relatively insensitive to temperature and humidity. Alanine dosimeters are available in the form of pellets or films and can be used for doses ranging from 10 Gy to 200 kGy. A reference calibration service using the alanine EPR system was developed and the scans were sent to the service center by mail. Currently the available system allows transferring the EPR scan to a NIST server for a calibration certificate. This way the procedure has been shortened from days to hours. ... 

Figure 3 illustrates rough dose-response model fits with human data for ionizing radiation and leukemia incidence from atomic bomb survivors (24). Data exist down to about the 10-5 lifetime risk per person exposed. This value is close to the region of regulatory interest, and relatively small risk differences are predicted by the three illustrated models in the dose range up to two orders of magnitude below the last observed dose value (ca. 5 rad). 

HPhe Fricke dosimeter (ferrous sulfate solutions) has been used to measure A the radiation intensity of various types of ionizing radiation sources since its development by Fricke and Morse in 1927 (2). It is widely accepted because it yields accurate and reproducible results with a minimum of care. This system meets many of the requirements specified for an ideal dosimeter (5, 9) however, it has a limited dose range, and for our applications it has been necessary to develop a dosimeter covering larger doses. Of the systems reviewed (6, 7), two (ferrous sulfate-cupric sulfate and ceric sulfate) showed the most promise for use with the radiation sources at the U. S. Army Natick Laboratories (8). Of these, the ferrous-cupric system has received the most use, and this paper describes our experience in using this system and suggests procedures by which it may be used by others with equal success. 

The level of the lesions is expressed as number of modifications per 109 bases and per either kj/m2 (UV-C laser pulse dose range 0—150 kj/m2) or per Gy of ionizing radiation (dose range 0-40Gy) [45]. 

In radiation processing practice the dose is sometimes measured by means of the alanine-EPR (CH3CH(NH2)C00H) dosimetry system (ISO/ASTM 51607 Alanine-EPR Dosimetry). The operation of the dosimeter is based on the generation of CHaCH COOH radicals by ionizing radiation. The read-out is made with electron-paramagnetic-resonance analysis. The nominal absorbed dose range is 1-10 Gy, with linear responses up to 10 Gy. 

Dose ranges considered low by various approaches to biological effects of ionizing radiation... 

Relative Dose Ranges from Ionizing Radiation... 

RELATIVE DOSE RANGES FROM IONIZING RADIATION... 

Metting, N. F., Ionizing Radiation Dose Ranges, Office of Science, U.S. Department of Energy , 2010. 

The modem ionization chamber, called a dose caUbrator in this appHcation, is capable of linear measurements of radioactivity having a precision in the range of several percent coefficient of variation over a range of 370 kBq (10 -lCi) to at least 370 GBq (10 Ci). This extraordinary range is the chief advantage of this instmment. It may only be used when the sample is known to have only a single isotope. It has no capacity to distinguish radiation from different isotopes. 

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