SYNCRAD¶

Summary

Activates synchrotron radiation emission for selected charged particles.

For SDUM = BMAX-REG¶

This setting is compulsory when the magnetic field is not constant and uniform, or is provided by a magfld.f routine (see Note 1).

WHAT(1): maximum magnetic field intensity (T) in the regions defined by WHAT(4)–WHAT(6). No default.
WHAT(2), WHAT(3): not used
WHAT(4): lower bound (or corresponding name) of the region indices with maximum magnetic field intensity given by WHAT(1).
Default: = 2.0
WHAT(5): upper bound (or corresponding name) of the region indices.
Default: = WHAT(4)
WHAT(6): step length in assigning indices.
Default: = 1.0
SDUM: = BMAX-REG

For SDUM = SYPRONLY, SYNCRALL, or blank¶

WHAT(1) > 0.0:

activates synchrotron radiation emission for the particles defined by WHAT(4), (5), and (6), down to the photon energy threshold given by WHAT(1) (GeV).

< 0.0:

deactivates emission for the selected particles

= 0.0:

ignored

WHAT(2) > 0.0:

upper threshold (GeV) for treating synchrotron radiation photons as optical photons. Photons with energies between WHAT(1) and WHAT(2) are loaded on the optical photon stack and transported as such. Photons above WHAT(2) are transported and interact using EMF.

< 0.0:

resets to default

Default

= 0.0

WHAT(3) > 0.0:

relativistic gamma factor (\(E/m\)) threshold. Only charged particles with gamma larger than this threshold emit synchrotron radiation photons. It cannot be set lower than 3.

< 0.0:

resets to default

Default

= 100.0

WHAT(4)

lower bound of the particle numbers (or corresponding name) for which synchrotron radiation is activated.

Default

= 1.0

WHAT(5)

upper bound of the particle numbers (or corresponding name).

Default

= WHAT(4) if WHAT(4) > 0; otherwise 1.0

WHAT(6)

step length in assigning particle numbers.

Default

= 1.0

SDUM

= SYPRONLY: emission restricted to primary particles only.

= SYNCRALL: emission activated for all generations.

Default

: blank SDUM activates emission for all generations.

Default

(option SYNCRAD not given): synchrotron radiation is activated for all generations of electrons, positrons and muons inside regions flagged for emission by ASSIGNMAt. The minimum photon energy is 1 eV, optical photons are not requested, and the minimum gamma factor is 100.

Notes

Setting the maximum magnetic field intensity is compulsory in all regions flagged for synchrotron radiation emission by ASSIGNMAt if the field is not constant and uniform, or is supplied by MAGFLD (see MGNFIELD). An approximate upper bound is sufficient; the value need not be exact to the last digit.
Emission activation is automatically ignored for neutral particles included in the selection by WHAT(4), (5), and (6) with SDUM = SYPRONLY, SYNCRALL, or blank.
With SDUM = BMAX-REG, the maximum field intensity is ignored for regions not flagged for synchrotron radiation by ASSIGNMAt.
The emission threshold can be as low as 1 eV (the default), even though FLUKA cannot deal with photons below 100 eV and no optical photon properties have been supplied. Most of the emitted power is generated, transported through vacuum, and dumped in the first material region encountered. This permits accurate description of the emitting particle’s energy loss and the power loading on, for example, a vacuum chamber.