SPOTTRAN

The SPOTTRAN card is used in conjunction with SPOTBEAM, SPOTPOS, SPOTTIME and SPOTDIR to define transformations of multiple beam spots. See SPECSOUR SPECSOUR.

Warning : These four cards are activated by indicating SDUM = BEAMSPOT in the SPECSOUR card. Barring this, the spot cards will be discarded.

See also SPOTBEAM, SPOTPOS, SPOTTIME, SPOTDIR

For SDUM = DIRECT or SDUM = INVERSE:

WHAT(1) =

index or name of the transformation to be applied to one or more beamlets. A -99999 value means unit transformation, whichever other negative value resets to default Zero is ignored

Default

0 no transformation

WHAT(2) =

index or name of a dummy transformation needed internally by the code. This transformation must be defined, and never used (it is internally overwritten)

Default

0 no transformation

WHAT(3)

not used

WHAT(4) =

lower bound of the spot number to which the transformation WHAT(1) apply. The spot numbers or names are those assigned using a SPOTBEAM card.

(“From spot ``WHAT(4)``…”)

Default

= 0

WHAT(5) =

upper bound of the spot number to which the transformation WHAT(1) applies. The spot numbers or names are those assigned using a SPOTBEAM card.

(“…to spot ``WHAT(5)``…”)

Default

= WHAT(4)

WHAT(6) =

step length in assigning the spot number.

(“…in steps of ``WHAT(6)`` ”)

WHAT(6) =

step length in assigning the spot number.

(“…in steps of ``WHAT(6)`` ”)

SDUM

= DIRECT: the WHAT(1) transformation is applied to the beam spot position and axes as well

INVERSE: the WHAT(1) inverse transformation is applied to the beam spot position and axes

BLANK : no transformation is applied to the beam spot position and axes

Default

no SDUM

Notes

When a beam spot in the range indicated by WHAT(4/5/6) is selected the transformation indicated in WHAT(2) is overwritten by the one indicated in WHAT(1). Please note that the transformation WHAT(2) is not restored after being overwritten

For SDUM = BACKTRAC:

WHAT(1) :

flag for enabling/disabling back-tracing

≥ 1.0:

back-tracing is enabled

≤ -1.0:

back-tracing is disabled

= 0:

ignored

Default

= 0, no back-tracing

WHAT(2) =

back-tracing distance (cm)

If WHAT(1) = 1 the beam position and angular spread are generated backward according to the nominal beam direction as defined by SPOTDIR at the requested distance from the spot nominal position point as defined by SPOTPOS (eg to generate them at a beam optics waist) and then the resulting beam moved forward by the same distance.

If WHAT(1) = 2 the beam position and angular spread are generated at the nominal spot point as defined by SPOTPOS (eg isocentre), then the beam is backtraced by a distance equal to what(2)

Default

= 0 no back-tracing

WHAT(3)

not used

WHAT(4) =

lower bound of the spot number to which the transformation WHAT(1) apply. The spot numbers or names are those assigned using a SPOTBEAM card.

(“From spot ``WHAT(4)``…”)

Default

= 0

WHAT(5) =

upper bound of the spot number to which the back-tracing applies. The spot numbers or names are those assigned using a SPOTBEAM card.

(“…to spot ``WHAT(5)``…”)

Default

= WHAT(4)

WHAT(6) =

step length in assigning the spot number.

(“…in steps of ``WHAT(6)`` ”)

WHAT(6) =

step length in assigning the spot number.

(“…in steps of ``WHAT(6)`` ”)