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Method

The phenomenological description of the response attenuation of organic scintillators [] is known as Birks' law:

The values quoted in [] for the parameters $C$ ₁, C₂

are:

These values have been measured for various scintillators. If the charge of the particle is greater than one, a better description can be obtained by correcting $C$ ₁ : $C$ ₁' = {7.212.6}C₁≈0.5714 C₁

The values of the parameters of Birks' formula (if defined) are in the ZEBRA bank next to the material bank:

JTM = LQ(JMATE-NTMED)

pointer to the current tracking medium bank;

JTMN = LQ(JTM)

pointer to the next bank to the current material one, where the specific tracking medium parameters are stored;

MODEL = Q(JTMN+27)

flag controlling the correction (

) for multiply charged particles:

$≠$ 1: correction is not applied;
=1: correction is applied;

C1 = Q(JTMN+28)

first parameter of the Birks' formula;

C2 = Q(JTMN+29)

second parameter of the Birks' formula.

These parameters are set via the GSTPAR routine, with names BIRK1, BIRK2 and BIRK3, respectively. For instance, to define the standard Birks' parameters for tracking medium ITM with correction for multiply charged particles, one would have to insert the following piece of code, after the definition of tracking media but before the call to GPHYSI

      CALL GSTPAR(ITM,'BIRK1',1.)
      CALL GSTPAR(ITM,'BIRK2',0.013)
      CALL GSTPAR(ITM,'BIRK3',9.6E-6)

PHYS340

Janne Saarela
Mon Apr 3 12:46:29 METDST 1995