Page History

Introduction

The Decarad system was developed at JLab - it consists of 10 radiation detecting heads (geiger-mueller (GM) tubes) that connect (signal & HV cables) to a central box. That box has a board inside for changing the HV level and reading out the GM tube signals. It's connected to the outside world with DB9 connector. On the other end of that cable is an RJ50 that plugs into a digi The center box is connected to a digi port server via DB9 at box to RJ50 at the digi, which is then connected to the outside world via ethernet. The software uses the epics tool Stream with an asyn connection to the digi to send commands to the center box to read and write. The software is part of the RadiationMonitoring slac epics package.

Proposed names:

There are two sets of decarads (10 heads + central unit) so the PVs listed above are doubled and differentiated by $(P).
Suggested $(P) = 

Cable Connection

Notes on cable connection (from email 8/12/21)

RJ50 cable/breakout (digiport server side)                              DecaRad Chassis DB9
Pins                                                                                                  Pins
1 blue/wht  TX-                                                                             2
2 org/wht    RX-                                                                             8
3 org      NC
4 green/wht   NC
5 green TX+                                                                                    7
6 brown/wht  RX+                                                                         3
7 brown    SGND                                                                            6
8 blk/wht    NC
9 black         NC
10 blue        NC

Hardware Components

Using Decarad frame.pdf as the basic design

...

Ethernet cable length calculation: max(min(distance to nearest))+40' = 145' (CM33)

Quotes

Quote from Teco Tech:

Original Files

Files from Bob and JLab folks (2020, 2021)