DR3 Active Geometry Cathodes

DR3 Cathodes

DRGeom and ADRGeom

DRGeom: Materials
ADRGeom: Individual (Aluminum) pads

8 Cathode Panels

DR3 Cathode: 8 equal Panels cover 360 degrees azimuth.
One of the seams between the cathodes is at 0 in azimuth

  • Numbering scheme: panel 0-7
  • gap between panels = 0.196"
    half gap (measured at outer radius)
    corresponds to (0.196"/2) / 31.64"= 0.00310 radians (.177 degrees)
  • Panel n:
    phiMin = n (pi/4) +0.00310 (radians) = n*45 + .177 (degrees)
    deltaphi = pi/4 - 0.00620 (radians) = 45.00 -0.354 (degrees)

Panel Materials

(DRGeom)
Honeycomb is wrapped (around) in Kevlar and Mylar. Aluminum pads are printed on mylar on low R-side, circuit is printed on the high R-side. 
Material            Rin                              Rout                                     
Aluminium           RInAl               ROutAl    =  RinAl    +    0.00068"
Mylar               ROutAl              ROutMlr1  =  RoutAl   +    0.0075"
Kevlar              ROutMlr1            ROutKvl1  =  RoutMlr1 +    0.010"
Honeycomb           ROutKvl1            ROutHny   =  RoutKvl1 +    0.22"
Kevlar              ROutHny             ROutKvl2  =  RoutHny  +    0.010"
Mylar               ROutKvl2            ROutMlr2  =  RoutKvl2 +    0.0075
Mylar/Kevlar are glued with high T epoxy
Polycarbonate Honeycomb/Kevlar glued w/Low T epoxy
There is a polycarbonate plastic frame around the honeycomb, with the same width as honeycomb, 0.22".
Sides of the frame are .373" wide, ends are 2.0" wide.
Question: True thickness? Is the difference significant?
Dan H. measures = 0.2621"
The Table above = 0.2557", i.e. 0.0063" smaller
Cathode outer radius
DanH. measures= inner radius + thickness =31.64"
table above = inner radius + thickness =31.6337"

Panel Geometry

  • Inner radius of the Aluminum, rInAL= 31.378" (DRGeom->ADRGeom)
  • 192 pads, each has active length 10.54 mm (ADRGeom)
  • Pad 0 is East-most
  • Pitch of the pads is derived as follows: L is measured from the z-center of the first pad to the z-center of the last pad: L=86.99"
    pitch = L/(191 pads) = 0.4554" (11.57 mm) (ADRGeom)
    Total length varies, it is approximately 87.5" (2222 mm). The survey (see below) is done only for active elements, i.e. the aluminum cathode pads. In DRGeom materials, we use nominal length corresponding to 192 pads and two half -gaps on each end.
  • Placement of panels and pads (DRGeom, ADRGeom )
    Four corners of the panel are surveyed as follows:
    A U-shaped tool is used to locate the edge of the 2nd pad from the end. The tool (M-o line in the drawing) is placed around the z-edges of the panel. One end (o) is placed at "beginning" of the 2nd pad, on the side of the panel facing the beam line. The other end (M) makes a marker M on the outer side of the pannel. R-z view: 
 

    ^  R 
    | 
    |  
     -----> z  

+----M                                                  M------+ Routside
|-====-====-====-====-       panel       -====-====-====-====- |		   
+-------o                                             o--------+ Rinside

In phi-z view, measured along the outside radius, the markers are placed:

  • 4.50" from low-phi edge
  • 4.25 " from high--phi edge

Each of the 4 M-markers is surveyed w/r to the DR3 endplate (surface 65?). It is a known distance C away in z from the beginning of the 2nd pad. If the marker M is distance X away from the DR3 endplate, the corresponding point at the beginning of the second pad is (X-C) away in z from the endplate.

In DR3Geom we will start with ideal geometry i.e. panels parallel to DR3 z axis. Survey values of the markers determine rotation of the panel from its ideal position. Rotation causes the z of the edge of the pad to be a function of phi, instead of being at a constant z.

The DRGeom panels are DetectorGeometry/ DGVolumeTubePhiSegments

ADRGeom Cathodes
  • ADRGeom/ADRCathodeStore
    attaches 8 Active panels to DRGeom
  • ADRGeom/ADRCathodePanel
    places 192 pads (ADRCathodePadInfo)
    Panel Object w/its access functions
  • ADRGeom/ADRCathodePadInfo
    Pad Object w/its access functions

ADRGeom Cathodes Access

Example of all access functions shown in /home/inga/cleo3/DRGeomProcessor/Class/DRGeomProcessor.cc
  • ADRGeom/ADRCathodeStore

    unsigned int numberOfPanels()
    unsigned int numberOfPadsInPanel()
    unsigned int numberOfPadsTotal()

    //panel object( panel #) and panel # (panel object)
    const ADRCathodePanel& panel( unsigned int iPanel );
    unsigned int panelNumber(const ADRCathodePanel& npanel)

    //Mapping (Panel 0-7 and Pad 0-191) <-> padID (1-1536)
    unsigned short panelOfPadID(const unsigned int PadId)
    unsigned short padInPanelOfPadID(const unsigned int PadId)
    unsigned int padID(const unsigned short Panel, const unsigned short Pad)

    still to add
    // const ADRCathodePanel& panelObject(
    DABoolean& success, const HepPoint3D& position )

  • ADRGeom/ADRCathodePanel

    // Cleo Lab Coordinates of the panel center and corners
    const HepPoint3D& point0();
    const HepPoint3D& cornerEastPhiMin()
    const HepPoint3D& cornerEastPhiMax() ;
    const HepPoint3D& cornerWestPhiMin()
    const HepPoint3D& cornerWestPhiMax();

    //LOCAL coordinates of the panel
    //phi is centered on 0, localPhiMin = - PhiDelta/2
    //z is centered on 0, local zmin/max = -/+halfLengthZ

    double panelRadius()
    double localPhiMin()
    double phiDelta()
    double halfLengthZ()

    unsigned int numberOfPads()

    const DGConstLabVolumePtr& panelVolume()
    //make pad
    ADRCathodePadInfo ADRCathodePadMk( unsigned int iPadID )
    //extract pad from the array made at initialization
    const ADRCathodePadInfo& ADRCathodePad
    ( unsigned int iPadID )

    // panels limits in z and phi
    double phiMin() ;
    double phiMax();
    double zMax()
    double zMin()
    // edges // success=.false. if parameter is outside the range
    double phiMinAtZ( DABoolean& success,double z)
    double phiMaxAtZ( DABoolean& success,double z)
    double zMinAtPhi( DABoolean& success,double phi)
    double zMaxAtPhi( DABoolean& success,double phi)

    still to add

    closest pad for the 3D nearby (at DR3 layer 47? ) point
    // const ADRCathodePadInfo& PadObjectClosest
    ( DABoolean& success, const HepPoint3D& iPoint )


  • ADRGeom/ADRCathodePadInfo

    // Cleo Lab Coordinates of the pad center and corners
    const HepPoint3D& point0()
    const HepPoint3D& cornerEastPhiMin()
    const HepPoint3D& cornerEastPhiMax()
    const HepPoint3D& cornerWestPhiMin()
    const HepPoint3D& cornerWestPhiMax()

    //LOCAL coordinates of the pad
    double radius()
    double localPadPhiMin()
    double padPhiDelta()
    double padHalfLengthZ()

    // limits in z and phi
    // double padGlobalPhiMin()
    // double padGlobalPhiMax()
    // double padGlobalZMax()
    // double padGlobalZMin()

    // edges // success=.false. if parameter is outside the range
    // double padPhiMinAtZ( DABoolean& success, double z) ;
    // double padPhiMaxAtZ(DABoolean& success, double z)
    // double padZMinAtPhi( DABoolean& success, double phi)
    // double padZMaxAtPhi(DABoolean& success, double phi)