Geometry of the CDC
<#1587#>Figure<#1587#> 4:
<#1588#>Geometry of the CDC<#1588#>
|
Fig.~#fig:CDC#204> shows a schematic of the CDC chamber displaying
some of the parameters that serve as input to the estimate:
- <#1590#>#tex2html_wrap_inline507#<#1590#>
- minimum radius of the CDC tracking volume
- <#1591#>#tex2html_wrap_inline509#<#1591#>
- maximum radius of the CDC tracking volume
- <#1592#>#tex2html_wrap_inline511#<#1592#>
- #tex2html_wrap_inline513#-coordinate distance from center of target to
downstream end of the CDC
Other parameters, not shown in Fig.~#fig:CDC#210> are:
- <#1597#>#math43##tex2html_wrap_inline515#<#1597#>
- minimum radius of the CDC stereo layers
- <#1598#>#math44##tex2html_wrap_inline517#<#1598#>
- maximum radius of the CDC stereo layers
- <#1599#>#math45##tex2html_wrap_inline519#<#1599#>
- number of radiation lengths measured transverse to
the tracking layers, <#215#>i.~e.<#215#>, at #tex2html_wrap_inline521# in the lab (#math46##tex2html_wrap_inline523#)
- <#1600#>#math47##tex2html_wrap_inline525#<#1600#>
- number of radiation lengths in the material
inside the CDC (target, scattering chamber, start counter, <#218#> etc.<#218#>), measured radially from the beam line.
- <#1601#>#math48##tex2html_wrap_inline527#<#1601#>
- number of radiation lengths in the
downstream CDC endplate, measured along the beam direction
- <#1602#>#tex2html_wrap_inline529#<#1602#>
- number of position measurements for a track which
passes through all layers of the CDC (sum of number of axial and
stereo layers)
- <#1603#>#math49##tex2html_wrap_inline531#<#1603#>
- number of position measurements in stereo layers
Table~#tab:cdc-geometry#223> gives the values for these parameters in
the current design.
<#1645#>Table<#1645#> 1:
<#1646#>Values of geometry parameters for the CDC in the current
design.<#1646#>
| Parameter |
Value |
|---|
| #tex2html_wrap_inline533# |
0.10960~m |
| #tex2html_wrap_inline535# |
0.56534~m |
| #tex2html_wrap_inline537# |
1.02~m |
| #math50##tex2html_wrap_inline539# |
0.16304~m |
| #math51##tex2html_wrap_inline541# |
0.39473~m |
| #math52##tex2html_wrap_inline543# |
0.03437 |
| #math53##tex2html_wrap_inline545# |
0.01437 |
| #math54##tex2html_wrap_inline547# |
0.02810 |
| #tex2html_wrap_inline549# |
25 |
| #math55##tex2html_wrap_inline551# |
8 |
|
For the CDC, #math56##tex2html_wrap_inline553# is the
radial thickness of the active volume. Then #math57##tex2html_wrap_inline555#
and #math58##tex2html_wrap_inline557#.
For tracks that exit the end of the CDC, the straight-line track
approximation is used to scale the number of measurements, the number
of radiation lengths and the transverse length of the track
(#tex2html_wrap_inline559#). Also for tracks exiting through the end-plate, the
material in the endplate is used as the material in front of the FDC.
