User specification of MINOS geometry
Note: This is still fairly preliminary.
This is documents most of the geometry/materials FFREAD cards
that were defined as of 5/1/96.
The details are still subject to change.
The use of FFREAD as the basic mechanism was chosen
simply for convenience (it is a CERN product, it is straightforward,
it works straight out of the box, it's already used by GEANT).
FFREAD long writeup @ CERN
Note: a common mistake is to overwrite previously set values by
re-issuing the same card without using a positioning indicator ('=').
In particular:
RTAG 'F1PL' 'F2PL' 'F3PL'
RTAG 'F4PL' 'F5PL'
leaves the array held by RTAG with the values:
'F4PL' 'F5PL' 'F3PL' .... remainder unchanged ...
There are two possible means of achieving what the user probably desired.
First, one can use continuation cards; these are lines without a key name
as the first element. Such lines are associated with the key that
immediately preceded them. The alternative is to explicitly position
the additions (eg. change the second card to
RTAG 4='F3PL' 'F5PL'). It is only necessary
to position the first element on a card as futher elements on the
same card are incremented from that position.
Choosing from defaults
Note:Default configurations will get implemented.
But the details of exactly what they are has not yet been decided.
When they are "set in stone" then they will get documented. Interested
parties should contact the author(s) about what defaults they wish to
see implemented.
SUPR card
Usage: SUPR isuper
Example:
SUPR 2
The SUPR card chooses the super-module
organization out of a predefined list, eg.
- 1 LST based Far detector (-1 for Near Hall)
- 2 FLS based Far detector (-2 for Near Hall)
- 3 RPC based Far detector (-3 for Near Hall)
The default would be to build the basic LST far detector.
Other pre-defined setups (including sub-variants) could be added to the list
upon demand.
Deviations from basics choices
For further discussion of what some of the terms in this section
mean, please refer to the documentation in the beginning
of the Geometry ADAMO specification.
Cards to specify the super-module organization
Example:
C overall detector layout
VHAL 700. 700. 4500.
NORF 0
NPLS 300 300 300 0
SSPA 2*100. 2*200. 2*150.
SX0 0. 0. 0.
SY0 0. 0. 0.
CSET 1 1 1
CCUR -1. -1. -1.
S1PA 'C1L1' 'C1L1' 'C1L1' 'C1L1' '....'
S1RM 'UVXY'
S2PA 'B4F4' 'B4F4' 'B4F4' 'B4F4' 'B4T1' '....'
S2RM 'UVUVX'
S3PA 'C1R1' 'C1R1' 'B1L1' 'B1L1' 'B4F4' 'B4F4' '....'
S3RM 'UVUVUV'
VHAL card
Usage: VHAL xhalf yhalf zhalf
The VHAL card sets the size of the 'HALL' volume.
Sizes are given as half-lengths in cm.
LTHK card
Usage: LTHK thickness
The LTHK card sets the thickness of the liner volume 'LINR'
surrounding the 'HALL' volume.
The thickness given in cm, which is added to the size of the 'HALL'.
This volume is used for limiting the range of particles that exit the
hall; if they leave the hall into the liner and then leave the liner
without re-entering the hall then they are deemed uninteresting and no
longer tracked.
VMAR card
Usage: VMAR xhalf yhalf zhalf
The VMAR card sets the size of the 'MARS' volume;
this is the size of the "world".
Sizes are given as half-lengths in cm. By default the world is very
large. User changes are limited to no smaller that the size set
by the VHAL + LTHK cards (or defaults).
NORF card
Usage: NORF inear
The NORF card sets whether the current configuration
is interpreted as being in the Near Hall or Far Hall. Any
negative value is taken as "Near".
NPLS card
Usage: NPLS nsup1 nsup2 ... nsupn 0
The NPLN card specifies the number of detector planes
(or passive-active pairs) in each
supermodule. This must be a multiple of the pair pattern
length (the number of detector planes in each module) since
fractional modules are never constructed;
it will be adjusted downwards to fit so that
NPairs = int(NModules) * int(NPairs/Module).
Up to 15 supermodules (a hex digit) can be formed; a list shorter
than the maximum is terminated by a value of zero. The length
of this list limits the number of values interpreted for the
other cards in this section.
SSPA card
Usage: SSPA up1 down1 up2 down2 ...
The SSPA card sets the additional spacing up- and downstream
of the super-module. This allows space for winding coil
cross connections and separates the super-mdoules.
Each super-module has a pair of values associated with it.
SX0/SY0 cards
Usage: SX0 xoff1 xoff2 ...
Usage: SY0 yoff1 yoff2 ...
The SX0 (SY0) card specifies the x (y)
offset of the super-module with respect to the centerline of the hall.
SiPA cards
Usage: SiPA 'pair' 'pair' 'pair' ... '....'
The SiPA card specifies the key and instance values
for the passive and active planes in each pair. The i value
runs from 1 to F (hex digit), allowing each super-module
to have an independent configuration. For each super-module up to 16
pairs can be specified (lists shorter than 16 should be terminated by
the string '....'). Each 4 character hollerith value is
constructed, in order, from the key-passive, instance-passive, key-active,
instance-active values (see Geometry.ddl
for the description of the terms).
In the above example, the first super-module is constructed of modules
each containing 4 C1 planes (concrete) each followed by a L1
limited-streamer tube detector.
The second super-module has magnetized iron B4 planes, the first four
have F4 liquid scintillator planes after them and the fifth is followed
by at T1 (test/trigger) plane. The final super-module has a concrete
planes, RPC's, magnetized iron planes, LST's, a (possibly) different type of
magnetized iron planes and FLS planes.
SiRM cards
Usage: SiRM 'rotation-keys'
The SiRM card defines the rotation applied to
the active partners in a module. Each super-module (i=1-9,A-F)
is constructed of
modules that may have different ordering for the rotations. There should
be a single key (X,Y,U,V) for each pair defined in the module (see
above for the description of the SiPA card).
Cards affecting the magnet coils
CSET card
Usage: CSET coil_org1 coil_org2 ...
The CSET card specifies the arrangement of coil winding
in the super-module. A preliminary mapping of index to arrangement is:
| index |
description |
|---|
| 0 |
no coils |
| 1 |
center bus; return bus in (-x,-y) corner |
| 4 |
center bus; return bus bars in 4 corners |
| 8 |
center bus; return bus bars at 45degree intervals |
| 10 |
"dipole configuration"; 4 bus bars at 50% of half-lengths, horizontal connections |
CCUR card
Usage: CCUR coil_I1 coil_I2 ...
The CCUR card is a multiplier applied to the field returned by
the field maps. Each super-module has an independent multiplier. By
default the original map effectively focussed mu+ and defocussed mu-.
This is reversed by setting the CCUR values to -1.
RMAG/CMAG cards
Usage: RMAG coil_radius
Usage: CMAG coil_clearance
The RMAG card determines the radius of the coil winding bus bars.
The CMAG card is used to determine the clearance necessary
between the cross connection bus bars on the front/back faces from
the first/last module. If insufficient space (see SSPA card
is allotted) then the cross connection are not inserted into the
super-module. This means that
2*(coil_radius+coil_clearance) should
be larger than the value given for either up or down
in the SSPA card.
RCOL/NCOL cards
Usage: RCOL rmin rmax
Usage: NCOL 'material_name'
The RCOL and NCOL define an insulating collar
that is inserted into the FLS and LST active planes at (x,y)=(0,0)
of the plane.
The two radii in the RCOL define the size of the annulus
(depth is set by the plane size). The first 4 characters on the
NCOL should match a defined material.
Cards to modify the plane geometry
The planes and, in the case of active detectors, their sub-components
are initialized by nominal_pln_geom.F.
This forms a base family of (1..9,A-Z) instances of each component to
choose from.
It may occur that none of the possibilities in a set is appropriate for a
desired configuration. The following section describes a method of
"tweaking" individual components away from their default values.
Cell-based geometries (LST,FLS,RPC)
For a given volume (a plane, extrusion, ...) there are associated
attributes (to use ADAMO terminology) containing a value.
The volume names use the key/instance for the first two characters.
| Type |
Volume Name |
Description |
|---|
| PL |
Plane |
clipping volume |
| BX | Box |
artifact for extrusion division (not user adjustable) |
| XT | Extrusion |
divided out of BX volume |
| CB | Comb |
inserted into extrusion |
| CV | Cover |
inserted into extrusion |
| CL | Cell |
displaces comb, touches cover volume |
| GV | Gap Cover-side |
dead region between the cover and extrusion |
| GB | Gap Comb-side |
dead region between the comb and extrusion |
In this figure:
- the XT (extrusion) volume is filled in black
- the CB (comb) volume is cyan
- the CV (cover) is green for the LST/RPC;
no CV is defined for the FLS extrusion
- the CL cell volume is yellow; this is
the active region where hits are generated.
- the GV (gap cover) and GB (gap comb)
volumes colored red. These are inactive regions in the RPC.
Tiled geometries (Emu)
These planes are covered by tiles set on a rectangular grid.
| Type |
Volume Name |
Description |
|---|
| PL |
Plane |
clipping volume |
| XT | Extrusion (tile) |
uniformly distributed across PL area |
| CL | Cell |
inserted into XT |
| CV | Cover |
inserted into XT |
Each tile
is a XT volume and should be specified with a BOX shape
and both a width and length. Embedded into the XT are
one or two CL (active) volumes and optionally CV volumes.
These a placed so that the CL (or CV) touches the
z surface(s). The number of tiles is determined by what is
allowed by integer numbers of XT volumes in each direction.
An emulsion plane (E?PL) would be defined to
be of the desired coverage size and made of air. Into that one inserts
tiles (sheets) of backing plastic. The front (and back) surfaces of
the plastic are then displaced by active cells of emulsion. If cover
volumes are requested they displace only plastic, not emulsion.
RVOL/RTAG/RVAL & IVOL/ITAG/IVAL cards
These cards must are used to form a triplet connecting a volume,
an attribute and a value. The real valued attributes must use
the 'R' cards, the others use the 'I' cards. Tag names must
be truncated to exactly four characters.
Example:
RVOL 'B7PL' 'B7PL' 'R7PL' 'R7PL' 'R7XT'
RTAG 'THIC' 'AIR1' 'THIC' 'AIR2' 'THIC'
RVAL 40. 50. 40. 50. 40.
IVOL 'B7PL' 'B5PL'
ITAG 'SHAP' 'BMAP'
IVAL 'TUBE' 2
| Tag |
Type |
Volume |
Description
|
|---|
|
SHAPe
|
hollerith
|
'??PL'
other
|
'BOX ',
'TUBE',
'PGON' (taken as an octogon)
'BOX ' only
|
|
MEDIum
|
hollerith
|
any
|
first 4 characters of tracking medium name
|
|
WIDTh
|
real
|
any
|
transverse size of volume
|
|
LENGth
|
real
|
any
|
length of volume (used in BOX shapes)
|
|
THICkness
|
real
|
any
|
depth of volume in z
|
|
AIR1gap
|
real
|
'??PL'
|
extra space in z allotted for "waviness" on front side of plane
|
|
AIR2gap
|
real
|
'??PL'
|
extra space in z allotted for "waviness" on back side of plane
|
|
BMAP
|
integer
|
'B?PL'
|
magnetic field map (0=none,1=old GUFLD).
|
|
CHILdren
|
integer
|
'??XT'
'??CB'
|
# of sub-volumes
for the extrusion: 1=comb alone, 2=comb+cover, >2=+gaps
for the comb: this is the number of cells
|
|
DIGType
|
integer
|
'??PL'
.
|
digitization scheme (1=LST, 2=FLS, 3=RPC)
if >10, upper part modifies selected method
|
Materials and Tracking Parameters
ABSA/ABSZ/ABSW/ABSD/ABSN cards
Usage: ABSA Aelement1 Aelement2 ...
Usage: ABSZ Zelement1 Zelement2 ...
Usage: ABSW Wfraction1 Wfraction2 ...
Usage: ABSD absorber density
Usage: ABSN 'absorber-name'
This collection of cards allow the user to specify their own admixture
of elements to create a material for using in 'Z' plane. Up to 10
elements can be combined; for each the user must specify the atomic
A, Z and proportion by weight. End the list with a value of 0 if
less than 10 elements are supplied.
LSTD/LSTW/RPCD/RPCW
Usage: LSTD density
Usage: LSTW argon co2 isobutane sf6 freon13B1
Usage: RPCD density
Usage: RPCW argon co2 isobutane sf6 freon13B1
These cards allow the user to change the composition and density
of the gas mixture in the LST or RPC. The density must be specified in
g/cm**3 (not g/liter). The proportions of the different gases is given
by numbers of molecules (for ideal gases, and we'll assume they are, this
means by volume). It is a good idea to explicitly set all the
fractions (to zero if appropriate) if any are changed from the defaults.
Sxxx/Cxxx/Fxxx (xxx = LST,FLS,RPC,EMU,FE,PB)
Usage: SXXX
tmaxfd stemax deemax epsil stmin [idray iloss dcute dcutm]
Usage: CXXX
cutgam cutele cutneu cuthad cutmuo bcute bcutm dcute dcutm ppcutm
Usage: PXXX
pair comp phot pfis dray anni brem hadr munu dcay loss muls stra
These cards allow the user to modify (most of) the behaviours of
GEANT while tracking in the LSTGAS MIXTURE, SCINT OIL (& PSTYRENE),
RPCGAS MIXTURE, EMULSION, IRON and LEAD tracking media. Each media has three
associated cards: the "S" card for tracking parameters (mostly step size);
the "C" card for energy cutoffs; and the "F" card for physics flags.
The "S" card retains the ability to modify limited "C" and "F" parameters
based on it's previous functionality, but use of this feature is
discouraged. The "S" and "C" cards take real values, while the "F" card
takes integer values.
SLST / SFLS / SRPC / SEMU / SFE / SPB
Tracking parameters:
- tmaxfd max. tracking step angle (degrees)
- stemax max. tracking step size (cm)
- deemax max. fractional energy loss per step
- epsil boundary crossing precision (cm)
- stmin min. step size (cm)
old format:
- idray delta-ray production flag [integer]
- iloss energy loss mechanism flag [integer]
- dcute electron generated delta-ray cut
- dcutm muon generated delta-ray cut
|
CLST / CFLS / CRPC / CEMU / CFE / CPB
Energy cutoff values (in GeV):
- cutgam cutoff for gammas
- cutele cutoff for electrons
- cutneu cutoff for neutral hadrons
- cuthad cutoff for charged hadrons
- cutmuo cutoff for muons
- bcute electron generated bremsstrahlung cut
- bcutm muon/hadron generated bremsstrahlung
- dcute electron generated delta-ray cut
- dcutm muon generated delta-ray cut
- ppcutm total energy cut for direct pair production by muons
|
FLST / FFLS / FRPC / FEMU / FFE / FPB
Physics process flags (see [PHYS001]):
- pair pair production flag
- comp compton scattering flag
- phot photoelectric effect flag
- pfis photon induced nuclear fission flag
- dray delta-ray production flag
- anni positron annihilation flag
- brem bremsstrahlung flag
- hadr hadronic interactions flag
- munu muon-nucleus interaction flag
- dcay decay in flight flag
- loss continuous energy loss glag
- muls multiple scattering flag
- stra collision sampling energy loss in thin materials flag
|
Note: the SXXX parameters have no effect unless
the AUTO 0 card is issued
Obsolete/removed cards
STDG card
Usage: STDG ilst ifls irpc iabs
Example:
STDG 1 1 1 2
The STDG card specifies the sets from which
instances of the components are chosen (or act as base families).
Differents sets are available for LST, FLS, RPC and absorber planes.
The default is all 1's (base setup for all components).
If the value is negative the members of the family may not be modified
by the means described below [now above].
As of 5/1/96 only one set for each type exists, and most rely on default
values. The locking mechanism is also not yet in place.
The actual available configurations can be gleaned from the
values given in the routine nominal_pln_geom.F and an
understanding of the format used as input to set_vol_par.F.
This handling needs serious work and is high on the to-do list.
Users who would like help modifying the geometry of planes or
components of those planes should contact R. Hatcher
(hatcher@astro.indiana.edu)
for additional help.
This card was removed 10/10/96. Multiple lists/sets of default
instances will not be supported. This cleans up the code and
eliminates some confusing aspects.
hatcher@astro.indiana.edu
Last modified: Tue Jul 16 08:52:09 CDT 2002