OT HV Distribution
Patch Panels
The 48 long-distance multi-wire cables (48 = 12 Cframes x 4 cables/Cframe)
go from the C-frames to the counting house D3, where the
HV power supplies
are located.
These 48 cables are not directly plugged into 48 outputs of the
HV power supplies, but are first patched on patch-panels provided with
HV jumpers.
The heart of this patching system are the patch boards. The front panel of
one patch board is shown in the photograph below;
as can be seen, each patch-board can service 18
Front-End Boxes, i.e. two quarters ("U"=upper and "L"=lower) and two layers.
Two patch boards are grouped into a patch panel. Each patch panel
services a half-station (two quarters, "U" and "L", and four layers).
The connectors used on the patch panels to interface to the
long-distance cables
are the
(Radiall)
HV multipin (52)
delivery chassis
(
Radiall code 691 803 004, EDH SCEM code 09.41.34.710.0).
There are three cabinets in the D3-D03 rack
for the three half-stations on the "A" side
(
T1-Q13, T2-Q13 and T3-Q13, resp.)
and three cabinets in the D3-D04 rack
for the "C" side (for
T1-Q02, T2-Q02 and T3-Q02, resp.)
The HV patch panels do not provide 1<-->1 connections to the HV power supplies.
Rather each patch panel provides an 8<-->1 connection between 8 (eight)
long-distance multi-wire (56x) cables to a half-station and 1 (one)
multi-wire cable to a
junction box located in the
HV racks in D3.
The scheme of this 8<-->1 connection is illustrated in the
figure below
(also available in
Autocad).
It is also graphically represented on the front-panel of each patch-board.
The main feature of this 8<-->1 connections is that they do not group the
8 HV lines (4 + 4) corresponding to the 2 "Upper" and "Lower"
Front-End Boxes
connected to each
detector module. Instead only the halves of the Front-End Boxes
corresponding to a
module monolayer are joined; namely, the 4 (2 + 2) HV lines of the
"Upper" and "Lower" monolayers of a module are joined together with the
4 (2 + 2) HV lines of the "Upper" and "Lower" monolayers of the next one.
