STJ Quick Start Guide v 2.01
April 1, 2021
Page 7
The jumpers at location J400 are set by default, as shown at left below, to connect the preamplifiers to
the built-in diagnostic pulser from the MPX-32D module via a software-controlled relay. To select the user
pulser input connected to the STJ I/O front-panel SMA connector, move both jumpers towards the
backplane connector, as shown at right below.
Fig 4: STJ Analog pulser selection jumpers
STJ I/O MODULE
XIA’s STJ I/O module must be installed in the left-most slot of the custom crate. It provides a “kill” switch
that overrides the software-controlled relay connection between the STJ detectors and the preamplifier
inputs, as well as the user pulser analog input and a diagnostic ‘channel 0’ output for each STJ Analog
module installed.
INPUTS, OUTPUTS AND CONTROLS
Name
Connector Type
Description
“Kill” switch
Toggle switch
Left-hand position: overrides software control of STJ
input relays—STJs are disconnected!
Right-hand position: software controls STJ input relays
Channel 0 Outputs
SMA (x4)
A single-ended version of the channel 0 preamplifier
output signal from each STJ Analog card in the custom
crate is routed to an SMA output connector for
diagnostic purposes.
User Pulser Input
SMA
The bottom-most SMA connector accepts a user-
provided diagnostic pulser input that can be routed to
all preamplifiers in the crate via software-controlled
relays.
The input is terminated to ground with a 50
Ω
resistor.
Note that the STJ Analog pulser selection
jumpers must be configured properly, as described
above.
