Sievert

Ra.dia.tlon Units. Units in use for activity of a radionucHde, 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. 

For this and subsequent demonstrations involving a heat source, use a gas torch such as the Sievert self-blowing propane outfit (W. A. Meyer Ltd., 9/11 Gleneldon Road, London SW16 2AU, or from most tool shops) this comprises 3.9-kg propane bottle, 3085 hose-failure valve, fitted pressure hose no. 16310,3486 torch, 2941 burner. 

Severe events with a frequency of >lE-6/reactor-year to result in <25R (0,25 sieverts) a half-mile from the reactor... 

Sv - Sievert radiation health effects (IJ/kg tissue) equivalent to ICX) REM. system - A collection of components to perform a purpose. 

It is essentially a phase diagram which consists of a family of isotherms that relate the equilibrium pressure of hydrogen to the H content of the metal. Initially the isotherm ascends steeply as hydrogen dissolves in the metal to form a solid solution, which by convention is designated as the a phase. At low concentrations the behaviour is ideal and the isotherm obeys Sievert s Law, i.e.,... 

Fig. 2. Example of a hysteresis loop on the isotherm pHj = /(H/Pd) obtained during absorption (upper curve) and desorption (lower curve) of hydrogen from palladium black at 100°C. After Sieverts and Danz (19).

The dose equivalent is the actual dose modified to take into account the different destructive powers of the various types of radiation in combination with various types of tissue. It is obtained by multiplying the actual dose (in gray) by the value of Q for the radiation type. The result is expressed in the SI unit called a sievert (Sv) ... 

The former (non-SI) unit of dose equivalent was the roentgen equivalent man (rem), which was defined in the same way as the sievert but with the absorbed dose in rad thus, 1 rem = 10 2 Sv. 

A 2.0-kg sample absorbs an energy of 1.5 J as a result of its exposure to (1 radiation. Calculate the dose in rads and the dose equivalent in rems and in sieverts. 

Jabaudon D, Sztajzel J, Sievert K, Landis T, Sztajzel R. Usefulness of amulatory 7 day ECG monitoring for the detection of atrial finrillation and flutter after acute stroke and transient ischemic attack. Stroke 2004 35 1647-1651. 

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