Radiation units used

Thus, for electromagnetic radiation of frequency, V, the wavelength in vacuum is longer than in other media. Another unit used to describe the wave properties of electromagnetic radiation is the wavenumber, V, which is the reciprocal of wavelength... 

An explanation of the many units used to describe the energy of electromagnetic radiation is provided in the following paper. 

The absorbed dose of radiation is the energy deposited in a sample (in particular, the human body) when it is exposed to radiation. The SI unit of absorbed dose is the gray, Gy, which corresponds to an energy deposit of 1 J-kg. The original unit used for reporting dose was the radiation absorbed dose (rad), the amount of... 

Parameters/Units Used in Electron Beam Radiation-Induced... 

Recently, Aida and Jiang [96] synthesized a series of dendrimers similar to those reported by McGrath and coworkers and reported photoisomerization of their core azobenzene units using infrared radiation. This new strategy holds immense potential for using dendrimers as light-harvesting matrices. 

Since 1925, The International Commission on Radiation Units and Measurements at Bethesda, Maryland has been publishing reports updating the definitions and units for measurements of various radiation-related quantities. Of these ICRU Reports, special mention may be made of reports no. 19 (1971) [radiation quantities and units], 33 (1980) [radiation quantities and units], 36 (1983) [microdosimetry], 47 (1992) [thermoluminiscent dosimetry], and 51 (1993) [radiation protection dosimetry]. A succinct description of various devices used in dosimetry, such as ionization chambers, chemical and solid-state dosimeters, and personnel (pocket) dosimeters, will be found in Spinks and Woods (1990). In this section, we will only consider some chemical dosimeters in a little detail. For a survey of the field the reader is referred to Kase et at, (1985, 1987), McLaughlin (1982), and to the International Atomic Energy Agency (1977). Of the earlier publications, many useful information can still be gleaned from Hine and Brownell (1956), Holm and Berry (1970), and Shapiro (1972). 

The units used to describe exposure and dose of ionizing radiation to living material are confusing, at best. First, the units have changed to an international system, SI, which stands for Systeme Internationale. We will use the SI system, but Table 12.2 compares the SI system with the older system. 

Codex General Standardfor Irradiated Foods and Recommended International Code of Practice for the Operation of Radiation Facilities Used for the Treatment of Food, CAC/Vol. XV-Ed. 1, Food and Agriculture Organization of the United Nations Rome, 1984. 

Rem unit used to measure radiation dose equivalents based on the quantity of radiation absorbed and type of radiation Residual Chlorine chlorine that has not combined with organic matter Resins sticky, liquid organic substances exuded from plants that harden upon exposure to air... 

Another unit used in photochemistry to express the energy of a quantum of radiation is the electron volt 1 eV = 96.49 kJ mol-1 = 23.06 kcal mol-1. Thus for A in nm... 

Absorbed dose Mean value of energy of the ionizing radiation absorbed by the unit of mass of the processed material. The unit of absorbed dose is 1 Gray (Gy) = 1 J kg or 1 kGy = ljg. The older unit, used officially until 1986 and still used occasionally in literature, is 1 megarad (Mrad), which is equivalent to 10 kGy. 

In 1993, ANSI issued a revised version of this standard (ANSI, 1993). The 30 cm diameter sphere of soft tissue of density 1 g cm was modified to a 30 cm X 30 cm X 16 cm slab of soft tissue with the composition defined by the International Commission on Radiation Units and Measurements [ICRU (1992)]. NVLAP and NRC have announced plans to use the revised version (NVLAP, 1994). 

Units used for radiation exposure, radiation dose and radiation dose equivalent are in transition (ICRU, 1980 NCRP, 1985). The relationship between the SI units and the conventional units are given in Thble 4.2. 

The curie is a huge unit of radioactivity and is approximately equal to the activity of one gram of radium. The inventories of radioactivity in a nuclear reactor upon shutdown are typically 109 Ci, whereas radiation sources used in tracer experiments have activities of p.Ci and the environmental levels of radioactivity are nCi or pCi. 

The gamma (y) radiation exposure units used to express radiation doses are as follows ... 

Max Planck determined in 1900 that energy is transferred by radiation in exact multiples of a discrete unit of energy called a quantum. Quanta of energy are extremely small, and may be found from the frequency of the radiation, v, using the equation ... 

Radiation Units. Units in use for activity of a radionuclide, ie, the curie, the roentgen (exposure to x and gamma rays), the rad (absorbed dose), and the rem (dose equivalent), should eventually be replaced by the becquerel (Bq), coulomb per kilogram (C/kg), gray (Gy), and the sievert (Sv), respectively. 

The synthesized samples were analyzed by X-ray powder diffraction for qualitative and quantitative phase identification. The unit used was a Philips Model with a vertical goniometer and a scintillation counter, utilizing Ni-filtered CuK radiation. For quantitative phase identification an external standard sample of ot-A O, was used. The percentage crystallization was calculated using thez "averaged peak intensities at 20 =35.2° and 20=47.3° of the reference sample and the peak intensity at 20=23.2° for the sample under study (31). 

The symbols for the quantities radiant energy through irradiance are also used for the corresponding quantities concerning visible radiation, i.e. luminous quantities and photon quantities. Subscripts e for energetic, v for visible, and p for photon may be added whenever confusion between these quantities might otherwise occur. The units used for luminous quantities are derived from the base unit candela (cd), see chapter 3. 

Five crystal modifications of Aspartame are known (Ajinomoto 1983 Hatada et al. 1985 Nagashima etal. 1987 Kishimoto andNaruse 1988 Tsuboi etal. 1991 Furedi-Milhofer et al. 1999). A number of analytical methods have been used recently to characterize three of them two hemihydrate polymorphs and a dihemihydrate (Leung etal. 1998a,b, Zell etal. 1999). The crystal structure of one of the hemihydrate forms, known as Form I, was published earlier (Hatada etal. 1985). More recently, synchroton radiation was used to determine the structure of the low humidity form (denoted Form Ib by the authors), with an asymmetric unit comprised of three aspartame molecules and two water molecules (Meguro et al. 2000). 

The fibers were annealed at 200 C for 5 min. in N2, wound parallel on a sample holder and flat plate X-ray photographs taken by exposing the fibers for 1 h (WAXS) to a beam collimated at 90° to the fiber axis, uatorial diffractometer traces of uniaxially oriented fibers were taken uring slit collimation. WAXS patterns were obtained on polaroid film and the difoctometer traces with a Siemens X-ray system. Nickel filtered CuKa radiation was used. The X-ray unit was operated at 30 KV and 20 mA. The sample to film distance was 71.4 mm. 

---