Analog Boards; Pmt Strips; X-E Board - Philips CARDIOMD Service Manual

Detectors
3.3.6

Analog Boards

The analog boards are located below the bronze-lead covers under the EDC Boards.
Figure 3.21 Location of analog circuitry
3.3.6.1

PMT Strips

The PMT Strips are passive boards interconnecting four PMT's each. They transfer power supply
voltages, including high voltage, autotune drive signals, tune reference voltages, working point
signals and control voltages for DynCor and threshold.
3.3.6.2

X-E Board

The X-E board sums the output from seven overlapping groups of PMT's in the X direction. Each
group sum is subjected to a DynCor process, and after that, a threshold is applied in order to
exclude those groups that are far away from the scintillations to eliminate noise. The information
from those groups is too noisy due to low photon statistics.
After threshold discrimination, the seven group sums are fed into a resistor matrix which feeds
into two summing nodes, X+ and X–. The resistor values of the matrix are such that the difference
between X+ and X– changes linearly with the X-positions of the scintillations.
The X-E board also provides an undiscriminated sum of all PMT signals which represents the
isotope energy.
3-28 CardioMD Service Manual
PMT strips
Power strip
X-E strip
Y strip
Tune strip
1MAN0158-H11 04-2005 CSIP Level 1