Posted by Peter Gumplinger (gum@triumf.ca) , Tuesday Jun 01, 2004 12:40
https://twist.phys.ualberta.ca/forum/view.php?site=twist&bn=twist_montecarlo&key=1086116775

Preliminary remarks:

Capitalized are the four letter G3 volume acronyms.

House-CenTR [HCTR] is the active tracking volume with chambers etc.

House-RiNG [HRNG] surrounds radially the active tracking volume and contains the
dead material around it.

HouSe-CoVer [HSCV] are 'lids' on both ends of HOUSe, i.e. the mother volume of
both HCTR and HRNG.

The YOKE has nothing to do with the VCIN volume list. The yoke is put directly
into Envelope-VOLume [EVOL]. However, this is not done by default, see the
e614.ffcards:

C
C ========== YOKE: IYOKE ==========
C
C     iyoke ==  0 0/>0 means do not/do insert a YOKE [0]
C
C YOKE 1

----------------------------------------------------------------------------

The list of VCIN volumes is exhaustive in that every track which leaves the
central tracking volume [HCTR] will go into one of them. Some of the volumes
listed are daughters of one of the other volumes in the list. These daughters
had to be included because they share a common boundary with their mother volume
and House-CenTRe [HCTR] and the G3 navigator will immediately drop into the
deepest daughter when crossing these boundaries.

The volume tree below shows the daughters only one volume down. It is by no
means the complete tree. If you wish to investigate further how the G3 geometry
(tree) is built, you can run int614_motif and use the command, for example:

/GEANT/DRAWING/DTREE 'EVOL' '2' '111'

etc.

----------------------------------------------------------------------------

WORLd [WORL] contains:

Envelope-VOLume [EVOL]

Envelope-VOLume [EVOL] contains:

HouSeWalL [HSWL]

and the 'upstream beam package':

HElium-Bag-Mantle [HEBM]
Beam-Pipe-WalL [BPWL]
Beam-Pipe-Mantle-Small [BMSN]
Beam-Pipe-Mantle-Large [BMLN]
T0-SCintillator-Volume [TSCV]

HouSe-WalL [HSWL] contains:

HOUSe [HOUS]
2 * HouSe-CoVers [HSCV]

HOUSe [HOUS] contains:

House-CenTR [HCTR]
House-RiNG [HRNG]

House-CenTR [HCTR] is the active tracking volume with chambers etc.

House-RiNG [HRNG] surrounds radially the active tracking volume and contains the
dead material around it.

HouSe-CoVer [HSCV] contains:

House-ENtrance1 [HEN1]
House-ENtrance2 [HEN2]

House-ENtrance1 [HEN1] (more downstream than HEN2) contains:

Beam-MYLar-Window (on its upstream side) - Aluminized-Mylar a qrt-thou thick.

House-ENtrance2 [HEN2] contains:

Housing-FlaNSh [HFNS] (cover ring which holds BMYL on the upstream side)

HElium-Bag-Mantle [HEBM] contains

HElium-BaG [HEBG]

HElium-BaG [HEBG] contains:

Muon-SCintillator-Volume [MSCV]
Beam-Pipe-WalL [BPWL]
Gas-ABsorber-Mantle [GABM]

G10-Ring-Foil-Support [GRFS] (around the tracking volume)

If you want to simulate including the dead material upstream but not the dead
material around the tracking chambers, your VCIN list should read:

VCIN 'SEC ' 'HRNG' 'GRFS'

On the other hand, if you want to simulate the dead material around the chambers
but not the upstream beam package, your VCIN list should read:

VCIN 'SEC ' 'HSCV' 'HFNS' 'HEBG' 'EVOL'

I shall add a one line comment for each volume listed to the VCIN/VCOT
explanation in the FFCARDS.

Attached is a G3 drawing of the upstream region. 'Radially outside' of HCTR is
everything beyond the horizontal blue lines on the right of the picture.
'Upstream' of HCTR is everything to the left of the most downstream long
vertical line.
[see forum for attachment]