In order to keep SixTrack as close as possible to its
original form (i.e. to avoid the need of multiples input files), it
has been decided to include a new block in the parameter file for SixTrack (fort.3).Here is a sample of what this block looks
like:
COLLIMATION
(1) .TRUE.
(2) 157 450000
(3) 3 0. 0.
5.703 0.0015 "dummy" 1.129E4 0.0000E+00
(4) .TRUE. 8.
9.3 9.3 10. 5.7 6.7 6.7 10.
900. 6.8 8. 7. 6.8
(5) 900. 900.
900. 900. 900. 900. 900. 900.
(6) 0 0. 0. 0. 0.
(7) 0. 0. 0. 0. 0. 0.
(8) 0. 0. 0. 0. 0. 0.
(9) 7.82E09
7.82E09
(10) .FALSE. .FALSE. 0. .TRUE.
TCP.D6L7.B1 .FALSE. .TRUE. .TRUE. .TRUE.
(11) 0. 0. 0.
0.
(12) 0. 0. 0.
0.
(13) .FALSE. 6.003
0.0015
(14) 0. 0.
.FALSE. .FALSE.
(15) 0 0.0025
(16) "allelemLTCPinjP1.data"
1
(17) .TRUE. .FALSE.
DEoENomP1VertInj 10001 1 1.0
NEXT
Description of the parameters:
(1) DO_COLL : logical, switches on/off the
collimation studies
(2) NLOOP : number of packs of 64 particles to be
tracked (breaks internal limitation)
MYENOM : energy of the beam to be tracked
(3) DO_THISDIS: integer, selects the type of
distribution used (see below)
MYNEX : size in sigma of the beam in the X direction,
defines distribution to be tracked
MDEX : smear in sigma of the
beam in the X direction, defines distribution to be tracked
MYNEY : size in sigma of the
beam in the Y direction, defines distribution to be tracked
MDEY : smear in sigma of the
beam in the Y direction, defines distribution to be tracked
FILENAME_DIS: name of the
distribution file to be read if DO_THISDIS is set to 4
ENERROR: energy spread of the tracked
beam
BUNCHLENGTH: bunch length of the
tracked beam in millimeters
(4) nsig_tcp3:
opening of the primary collimator in IR3 (in sigmas)
nsig_tcsg3: opening of the secondary graphite collimator in
IR3 (in sigmas)
nsig_tcsm3: opening of the secondary metallic collimator in
IR3 (in sigmas)
nsig_tcla3: opening of the active absorbers in IR3 (in sigmas)
nsig_tcp7: opening of the primary collimators in IR7 (in
sigmas)
nsig_tcsg7: opening of the secondary graphite collimator in
IR7 (in sigmas)
nsig_tcsm7: opening of the secondary metallic collimator in
IR7 (in sigmas)
nsig_tcla7: opening of the active absorbers collimator in IR7
(in sigmas)
nsig_tclp: opening of the physics debris collimator (in
sigmas)
nsig_tcli: opening of the absorbers for injection protection
(in sigmas)
NSIG_TCDQ: opening of the beam dump
protection collimator (in sigmas)
NSIG_TCSTCDQ: opening of secondary
collimator dedicated to beam dump (in sigmas)
NSIG_TDI: opening of the injection
protection collimator (in sigmas)
(5) nsig_tCTH1:
opening of the horizontal tertiary collimator in IR1 (in sigmas)
nsig_tCTH2: opening of the horizontal tertiary collimator in
IR2 (in sigmas)
nsig_tCTH5: opening of the horizontal tertiary collimator in
IR5 (in sigmas)
nsig_tCTH8: opening of the horizontal tertiary collimator in
IR8 (in sigmas)
nsig_tCTV1: opening of the vertical tertiary collimator in
IR1 (in sigmas)
nsig_tCTV2: opening of the vertical tertiary collimator in
IR2 (in sigmas)
nsig_tCTV5: opening of the vertical tertiary collimator in
IR5 (in sigmas)
nsig_tCTV8: opening of the vertical tertiary collimator in
IR8 (in sigmas)
(6) N_SLICES : surface model of the jaw  number of slices in
which each jaw should be cut
SMIN_SLICES : surface model of the jaw  s
position for the start of the slicing
SMAX_SLICES : surface model of the jaw  s
position for the end of the slicing
RECENTER1 : surface model of the jaw  moving the
1st jaw to the new smallest opening
RECENTER2 : surface model of the jaw  moving the
2nd jaw to the new smallest opening
(7) FIT1_1 : surface model of the jaw  order 0 of the
polynomial fit for the 1st jaw
FIT1_2 : surface model of the jaw  order 1 of
the polynomial fit for the 1st jaw
FIT1_3 : surface model of the jaw  order 2 of
the polynomial fit for the 1st jaw
FIT1_4 : surface model of the jaw  order 3 of
the polynomial fit for the 1st jaw
FIT1_5 : surface model of the jaw  order 4 of
the polynomial fit for the 1st jaw
FIT1_6 : surface model of the jaw  order 5 of
the polynomial fit for the 1st jaw
SSF1 : surface model of the jaw  scaling factor
of the polynomial fit for the 1st jaw
(8) FIT2_1 : surface model of the jaw  order 0 of the
polynomial fit for the 2nd jaw
FIT2_2 : surface model of the jaw  order 1 of
the polynomial fit for the 2nd jaw
FIT2_3 : surface model of the jaw  order 2 of
the polynomial fit for the 2nd jaw
FIT2_4 : surface model of the jaw  order 3 of
the polynomial fit for the 2nd jaw
FIT2_5 : surface model of the jaw  order 4 of
the polynomial fit for the 2nd jaw
FIT2_6 : surface model of the jaw  order 5 of
the polynomial fit for the 2nd jaw
SSF2 : surface model of the jaw  scaling factor
of the polynomial fit for the 2nd jaw
(9) EMITX0 : geometric emittance in the horizontal plane
EMITY0 : geometric emittance in the
vertical plane
(10) DO_SELECT : logical, does a dedicated study of
selected collimator (see NAME_SEL)
DO_NOMINAL : logical, switches on/off
the use of design β values of collimators
RND_SEED : seed studied; if set to 0, seed
will be selected randomly for every run
DOWRITE_DIST : logical, saves or not
the initial distribution to be tracked
NAME_SEL : name as in the fort.2 file of
the collimator one wants a dedicated study
DO_ONESIDE : logical, switches on/off
the collimator being onesided
DOWRITE_IMPACT : logical, saves the
impact parameters for each collimator
DOWRITE_SECONDARY : logical, writes a
2ry halo file based on normalized amplitude
DOWRITE_AMPLITUDE : logical, writes
checking files for amplitude, closed orbit...
(11) XBEAT : offset in X for the computation of collimator in
case of betabeating
XBEATPHASE : phase offset in X for the
computation of collimator in case of betabeating
YBEAT : offset in Y for the computation of
collimator in case of betabeating
YBEATPHASE : phase offset in X for the
computation of collimator in case of betabeating
(12) C_RMSTILT_PRIM : rms value of tilt to apply to primary
collimators
C_RMSTILT_SEC : rms value of tilt to apply to
secondary collimators
C_SYSTILT_PRIM : systematic value of tilt to
apply to primary collimators
C_SYSTILT_SEC : systematic value of tilt to apply
to secondary collimators
(13) RADIAL : logical, switches on/off the radial
distribution
NR : size of the beam to be tracked in number of
radial sigmas
NDR : smear of the beam to be tracked in number
of radial sigmas
(14) DRIFTSX : to apply an emittance drift in x direction
DRIFTSY : to apply an emittance drift
in y direction
CUT_INPUT : logical, formerly
used to select particles to be tracked (set .FALSE.)
SYSTILT_ANTISYM : logical, to
deduce C_SYSTILT to C_RMSTILT instead of adding
(15) IPENCIL : resets original distribution to pencil beam
distribution on selected collimator
PENCIL_OFFSET : size in number of
sigmas of the desired impact parameter
(16) COLL_DB : name of the collimator database; must be quoted
IBEAM : "name" of the beam
tracked (1 or 2) => TO BE UPGRADED
(17) DOWRITETRACKS : logical, writes secondary/tertiary halo
files
CERN : logical, switches on/off
to cut halo files in separate pieces, one per 64 particles
CASTORDIR : name of the run; MUST BE
EXACTLY 16 characters
JOBNUMBER : 5 digit number, name of
the complement to the name of the run (gives seed)
SIGSECUT2 : cut in square sigmas x/y
for saving particles (e.g. 64 for a cut at 8 σ_{x}/σ_{y})
SIGSECUT3 : cut in square sigmas
radial for saving particles (e.g. 90.25 for a cut at 9.5 σ_{r})
One should know that a large value for NLOOP combined with
DOWRITE_TRACKS set to .TRUE. may create really huge output files,
depending on the optics you run with.
For example, in our current simulations, a run with NLOOP = 50 (i.e.
simulations over 3200 particles) for the LHC collision optics will
produce a tracks2.dat file of 2.8 Go
(!!), for just 1/1000th of the statistics we need.
Remark: the flag DO_THISDIS provides the user with
4 different options:
 DO_THISIDS = 1 : distribution in
the plane for which the parameters are specified ONLY
 DO_THISIDS = 2 : distribution in
the plane for which the parameters are specified +
1 sigma distribution in the other plane
 DO_THISIDS = 3 : distribution in
the plane for which the parameters are specified +
1 sigma distribution in the other plane
+ energy distribution and bunch length
according to the values given with ENERROR and BUNCHLENGTH
 DO_THISIDS = 4 : reads an external file that
contains the beam distribution to be tracked.
