TOF Design Decision Page

• 3Pack Distribution into the Shelves
• Design of Inner PMT Covers
• Scintillator Bar Wrapping and Painting
• Alignment of 3 Packs with the CDF Detector
• Design of Outer PMT Cover
• Supply and Signal Cable Routing

 DECISIONS 25/01/2000: 3Pack Distribution into the Shelves
 =========================================================
 
 =========================
 | Shelf | Grade | 3pack |
 =========================
 | 01    | B-    |  T14  |
 | 02    | C(+)  |  T11  |
 | 03    | B+    |  T13  |
 | 04    | B     |  T09  |
 | 05    | C     |  T17  |
 | 06    | B+    |  T16  |
 | 07    | A+    |  T05  |
 | 08    | A+    |  T19  |
 | 09    | A(+)  |  T29  |
 | 10    | A+    |  T20  |
 =========================
 | 11    | A+    |  T01  |
 | 12    | A+    |  T02  |
 | 13    | A+    |  T25  |
 | 14    | A(+)  |  T18  |
 | 15    | A+    |  T23  |
 <<<< =============== >>>>  the middle of the detector
 | 16    | A++   |  T22  |
 | 17    | A++   |  T21  |
 | 18    | A++   |  T24  |
 | 19    | B-    |  T10  |
 | 20    | A     |  T12  |
 =========================
 | 21    | B-    |  T15  |
 | 22    | ***** |  T27  |
 | 23    | C     |  T26  |
 | 24    | C     |  T30  |
 | 25    | C     |  T28  |
 | 26    | A+    |  T06  |
 | 27    | B+    |  T07  |
 | 28    | A     |  T08  |
 | 29    | A+    |  T03  |
 | 30    | A+    |  T04  |
 =========================

 DECISIONS 09/09/1999: Design of the Inner PMT Support
 =====================================================

 The design of the inner PMT cover is partially decided and handed out
 to production. The Winston cone and the plastic piece for protecting
 the PMT pins are finalised.

The drawings are available as IDEAS-D version 6 documents and as
 postscript files for printing.

  Winston Cone          (IDEAS-D, PS)
  Tube Holder           (IDEAS-D, PS)

 The interface to the outer structure is defined by the overall length
 the big middle whole and two small wholes for the screws of the cover.

 DECISIONS - 26/08/1999: Scintillator Bar Wrapping and Painting
 ==============================================================

 Matthews Monte Carlo study shows that the colour of the bar wrap does
 not influence the signals significantly and thus we stay with white
 wrap for each bar (non adhesive material).

 The Winston cone is also not affected by wrapping thus it stays as
 is.

 The scintillator ends which are not covered influence - due to
 reflection - the signal amplitude by 10%. This is not a very large
 effect but it is worth the effort to paint the end of the PMT covers
 black to reduce the reflection.

 Further to reduce cross talk within the 3pack the middle bar will be
 additionally wrapped in blck Tyvak paper and the Marvelguard paper
 around the 3 pack will be turned around with the black side at the
 inner side.

 DECISIONS - 19/08/1999: Alignment of 3 Packs with the CDF Detector
 ==================================================================

 The CDF physics groups leader have been asked for arguments for
 the scenarios of either ligning up the scintillator bar edge with the
 crack in the CDF calorimeter or covering this gap by aligning the
 middle of the bar with the crack.

 No solution was really favoured and it has been decided to align the
 edges. Thus the edge of the top most scintillator in the first 3pack
 starts at 12 o'clock.

 DECISIONS - 14/09/1999: Design of the Outer PMT Cover
 =====================================================

 * REVISED DESIGN AS OF 14/09/1999
   reduced size of the left and right covers by shaving-off material

* REVISED DESIGN AS OF 02/08/1999
   fixed inconsistency in drawings on left sliding cover
   (45 degrees, instead of 35 degrees, for the bore position)

 * REVISED DESIGN AS OF 30/07/1999
   fixed inconsistency in drawings on all left/right covers

 * REVISED DESIGN AS OF 02/07/1999
   fixed design error for the sliding slots

 The design of the PMT cover has been split into two parts which can
 be treated independently since the interface is well defined. The one
 part is the inner structure which consists of the PMT, its base,
 preamp and further parts. The second part is the container which
 provides the connection between bars within the three-packs and
 between the three-packs themselves.

 The latter one has been presented at the meeting and has been signed
 off as is. After some problems were identified in the first prototype
 the design has been improved and signed off again for production.
 Due to the fact that space is very tight the design has been
 optimised to reduce the size.

 Further to equalize length variations between the scintillator bars
 the connections on one side of the three-pack allow for a certain
 shift (sliding connection). As a consequence there are six different
 types of containers. The drawings are available as IDEAS-D version 4
 documents (in inches and millimeters) and as postscript files for
 printing.

  PMT FIXED COVER - CENTER   (IDEAS-D, PS)
  PMT FIXED COVER - RIGHT    (IDEAS-D, PS)
  PMT FIXED COVER - LEFT     (IDEAS-D, PS)
  PMT SLIDING COVER - CENTER (IDEAS-D, PS)
  PMT SLIDING COVER - RIGHT  (IDEAS-D, PS)
  PMT SLIDING COVER - LEFT   (IDEAS-D, PS)

 The interface to the inner structure is defined by the overall length
 the big middle whole and two small wholes for the screws of the cover.

 DECISIONS - 08/04/1999: Supply and Signal Cable Routing
 =======================================================

 Supply and signal cables to and from the PMTs will be pulled from
 both sides to the TOF system. This facilitates the design of the
 Mechanical parts and makes the installation simpler.

 To have a handle on the possible problems arrising from the fact that
 the signals from one bar are read out from different modules each
 crate will have one pair of PMTs which could be connected in a one
 sided readout. Therefore cables have to be forseen.