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.

patch board front patch board back

Two patch boards are grouped into a patch panel. Each patch panel services a half-station (two quarters, "U" and "L", and four layers).

patch scheme T1-Q13

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

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.)

Q13 PP Overview

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.

FE mapping FE Box

FE mapping