Target/I-counter radius and thickness in UMC

                               Takeshi K. Komatsubara (KEK)
                               latest update: 2003-Jan-22(Wed)

 *This txt is based on a reply from Peter Meyers (Princeton) in Jul 1999
  on the TGT geometry.


> 
> I would verify the IC/VC radii in UMC. 
> 
> Here is a schematic drawing of the Target subsystem
>  ( taken from $UMC_SOURCE/geomtg1.cdf ) : 
> C
> C .........................................................................
> C                         JTGDC  (in BF subsys)
> C ..................................................................._RTGBF
> C                         JOUTTG (in TG subsys)
> C ....................................................________________RADOUT
> C         JOUTDG                        :   : VC gap  |       VC
> C                                       : J :_________|_______________WIHEXO
> C ......________________________________: D |  IC      |   ICLP
> C   g   |                 |   |     |B|B| G |__________|______________WTAR
> C   a   |      degrader segments    |4|4| T :g|
> C   p   |      (BeO, gaps, PbGl)    |u|v| G :a|    target (one region)
> C   1   |                 |   |     | | |   :p|
> C       |                 |   |     | | |   :2|
> C ------+-------+---beam axis--+------+------+------+------+------+------+-----
> C
> and in $UMC_SOURCE(or $KOFIA_KUMC)/geodat.cdf , 
> 
>  WTAR	(target outer radius)	5.98
>  WIHEXO (IC outer radius)	6.615
>  RADOUT (VC outer radius)	7.091	and
> 
> 
> 
> In $KOFIA_TT/sqgeom.cdf by Jim  
>  (though these geometrical parameters are not used in KOFIA analyses ),  
> 
> c	air to inner radius of ICounters 5.980 cm         2.16  cm^2
> c ...
> c	outer radius of ICounters = inner radius of Vcounters  6.683 cm
> c	outer radius of VCounters  7.260 cm
> 
> 
> Do you think we should change WIHEXO and RADOUT in UMC 
> to be 6.683  and 7.260  ? 
> 
> 
> * The Degrader/B4 radius in UMC (RDGTG) is 5.35 in geodat.cdf . 
>   How can I veryfy the parameter ? 
> 


   I worked pretty hard on this.  Take a look at the UMC help file under the
BNL-787 web site:

   DETECTOR_VERSIONS
      TG_DG_BM 
         Target_2
            dimensions 
                 http://www.phy.bnl.gov/e787/umc/umc_5.html#Ref8

This is a list of the various versions of the dimensions that I was able to 
compile.  (Sorry: this is a table that doesn't come out well in HTML.  Use
"View Source" to see it clearly in ASCII).  The issue is air gaps.  They
exist in the real target, but not in the UMC one.  So, the choice is whether
you want the outside radius to be accurate, or the thickness of plastic.
I chose the latter.  You and Jim should take a look at my table and see
what you think.

                                          Peter


[ http://www.phy.bnl.gov/e787/umc/umc_5.html#Ref8 ]

dimensions

These are the dimensions used for the new target subsystem. I list various
data and sources and the ones finally used. Items in [] are from Kelvin, and
the ones with * were scaled by him from a TRIUMF drawing.

param definition values

ZDGSTG(1) length of BeO TN237: 15 or 16 X .975"; Kelvin: 15" PK: meas .975"
[15x0.982"]: 1992,1994 runs, BeO thickness =15x14.73 cm =37.41 cm varies and
not exactly flat. USE 37.41 CM

ZDGSTG(2) gap between BeO TN237: I calc 0.4 cm; Kelvin doesn't recall a gap
and PbGl *[1/16"] = .159 cm Akira: black plastic light shield ~.3-.4 cm
Takashi: 0 (sure) USE 0.3 CM -- AND MAKE IT PLASTIC

ZDGSTG(3) length of PbGl TN237: 10 cm; Kelvin: 4"=10.16 cm [4"] Akira: 10 cm
as ordered from company USE 10.0 CM

ZDGSTG(4) gap between PbGl TN237: I calc .33 cm and B4 *[0.04"] = .102 cm
Takashi: .33 cm about right USE 0.33 CM

ZGAPTG gap between B4 TN237: 0.0 cm; Kelvin: a little less than 1/4" and
ends of IC *[1/8"] = .3175 cm USE 0.3 CM ????????????

RDGTG radius of PbGl TN237: 5.6 cm; Kelvin 4.212"=5.35 cm (also used for B4
and degr) [4.212"] = 10.7 cm/2=5.35 cm Akira: 10.7 cm, lightguide fm 10.8 to
12.9 cm part of lightguide is leadglass, part lucite PK: "radius" of B4:
match TG, diam=12 cm Takashi: 5.35 cm. Is 5.6 cm at front USE 5.35 CM

ZXYHOD thickness of each TN237: .635 cm B4 plane [1/4"] PK: .25" = .635 cm
USE 0.635 CM

WTAR RADIUS of target DWG: 5.95 cm; SQGEOM: 5.98 cm (IR of IC): close
(=inner rad of IC) enough [2.375"] = 6.0325 cm USE 5.98 CM

WIHEXO Outer radius of IC SQGEOM: 6.683 cm. This makes IC .277" thick.
(=inner rad of VC) Is this correct? [2.625"] 6.6675 cm USE 6.615 CM = 5.98 +
.25"

RADOUT Outer radius of VC DWG: 7.06 cm; SQGEOM: 7.26 cm [2.842"] = 7.219 cm
USE 7.091 CM = 6.615 + 3/16"

ZICTR Length of IC (which DWG: 25.37 cm = 9.99"; Jim: <9.5" everyone seems
to agree are centered on z=0) [9.55"] = 24.257 cm USE 24.257 CM

ZSVETO z of start of VC DWG: 11.445 cm [4.5"] = 11.43 cm USE 11.43 CM

ZICOH overhang of IC beyond DWG = Kelvin = .25" = .635 cm end of target. USE
0.635 CM

DFIB size of main fiber DWG: .492 SQGEOM: scint+clad+wrap=.488, rest air USE
0.492 CM (no good way to treat air)

-- thickness of IC [1/4"] = .635 cm -- thickness of VC [3/16"] = .476 cm

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