Syntax:
DECAY: STOL={step-size tolerance}
Example:
DECAY: STOL=0.01
Purpose: Set the step-size tolerance. Changes in the instantaneous dose rate are modeled using a series of sequential time intervals. The dose rate within each of these time intervals is a constant. As the value of STOL decreases, the size of each time step decreases and the exponential nature of the true dose rate function is modeled more accurately.
Data Type: real
Unit: Gy/hour
Default: 10-3
Comments: Values for STOL in the range from about 0.05 to 1.0E-03 should be adequate in most cases. The time to execute a biophysical simulation tends to increase as the number of steps increases (i.e., as STOL decreases). The TCUT and DCUT parameters are used to limit damage repair simulations of damage repair processes to a finite time period. This procedure is justifiable on the grounds that, at some point in time, the activity of the radiation source becomes so small that any further radiation killing of the cell population can be neglected. Repopulation effects may also suffice to compensate for any radiation killing (i.e., the surviving fraction remains constant). The TAD parameter represents the total absorbed dose delivered to the cell system over all time. The SAD parameter is the effective dose delivered to the cell system in a finite time interval (0, TCUT). The total delivered dose is related to the effective delivered dose by SAD=(1-DCUT)*TAD.
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