TCQUENCH

Summary

Sets time cutoffs and/or quenching factors when scoring using the USRBIN or the EVENTBIN options. ​​​

See also TIME–CUT ​

WHAT(1) > 0.0:

time cutoff for scoring (seconds)

< 0.0:

resets any previously requested time cutoff to default (\(\infty\))

= 0.0:

ignored

WHAT(2) > 0.0:

first Birks​​​ law coefficient in g/(MeV\(\cdot\)cm\(^2\))

= 0.0:

ignored

< 0.0:

resets both Birks law coefficients to default = 0.0

WHAT(3) > 0.0:

second Birks law coefficient in g\(^2\)/(MeV\(^2\cdot\)cm\(^4\))

Default

= 0.0

WHAT(4) =
lower index bound of binnings (or corresponding name) in which the requested scoring time cutoff and/or Birks law coefficients must be applied
(“From binning ``WHAT(4)``…”)
Default

= 1.0

WHAT(5) =
upper index bound of binnings (or corresponding name) in which the requested scoring time cutoff and/or Birks law coefficients must be applied
(“…to binning ``WHAT(5)``…”)
Default

= WHAT(4)

WHAT(6) =
step length in assigning indices.
(“…in steps of ``WHAT(6)`` ”)
Default

= 1.0

SDUM

: not used

Default

(option TCQUENCH not given): no time cutoff for scoring and no quenching of dose binning


Notes

  1. Binnings are numbered​ sequentially in the order they are input via the USRBIN or EVENTBIN options. Of course, for quenching to be applied the quantity binned must be energy (generalised particle 208 or 211). The energy deposited in a charged particle step is “quenched” according to Birks law, i.e. it is weighted with a factor dependent on stopping power​ \(S = \mathrm{d} E/\mathrm{d} x\):

    \[\mathrm{d} E' = \frac{ \mathrm{d} E}{1 + B S + C S^2}\]

    with \(B\) = first Birks parameter and \(C\) = Chou​​ or second Birks parameter [Bir64].

  2. The time cutoff is useful in order to score only within a time gate​ between \(t~=~0\) and \(t~=~t_{cutoff}\)

  3. The scoring time cutoff should not be confused with the time cutoff for transport (see TIME–CUT). Particles outside the time gate defined by TCQUENCH are still transported and can contribute to scoring in regions and in binnings having a different time scoring cutoff.

  4. If the source has been defined as a radioactive isotope ​ (command BEAM with SDUM = ISOTOPE), transport of each isotope decay secondary starts with an age​ equal to the time of decay.

Example:

*...+....1....+....2....+....3....+....4....+....5....+....6....+....7...+...8
TCQUENCH        20.0   7.35E-3   1.45E-5       4.0      10.0       3.0
*  Set a 20 sec time scoring cutoff for binnings 4, 7 and 10, and apply to
*  them the NE213 scintillator Birks parameters published by Craun and
*  Smith, Nucl. Instr. Meth. 80, 239 (1970)