RoentDek DLD120, Руководство пользователя

Страница: 24 / 80

Page 24 of 80 MCP Delay Line (Version 6.2.90.5)
Figure 2.30: The ATR19 module
The ATR19 can also be operated as a non-symmetric (single input) amplifier with 50 Ω impedance to ground, inverting (-) or
non-inverting (+). The non-symmetric operation is the default mode for the use of a delay-line detector in combination with
the FT12(16)-TP feedthrough and decoupling plugs.
The outputs of the ATR19 allow verification of the signals after the first amplification stage on the DLATR board (“analog”
signal) and of the NIM or ECL timing output signals. Amplification, trigger threshold and timing signal width can be adjusted
by potentiometers (default) or externally by DC levels (0 to +5V), the CFD “walk” adjust is automated (push-button). The
double-hit dead-time of the CFD-outputs is about 20ns, depending on the input signal width.
Since the amplifier inputs are internally not tolerant to both signal polarities (no bipolar amplification), it is required to feed
signals into the inputs of corresponding polarity. Therefore positive input signals (e.g. the signal from the MCP) must be
connected via the inverting (-) input and negative signals have to be connected via the non-inverting (+) input. To ensure a
proper 50 Ω termination of single polarity signals the other side of the internal amplifier input must be terminated to ground
(see chapter 2.6.1).
The recommended readout version of the
RoentDek
delay-line detectors involves the FT12(16)-TP plug with internal
signal transformers for the delay-line signals.
When the
ATR19 is delivered, channel 1 and 2 are by default prepared for positive input polarity (inverting) and the other
channels (used for the delay-line signals) for negative (non-inverting) signal polarity. If the voltages to the detector are
supplied in the recommended way the signal from the MCP front or back contact (positive) has to be connected to ch1- or
ch2- and the delay-line signals to ch3+ to ch6+ (or ch8+). Changing these settings requires to open the ATR19 module (see
chapter 2.6.5).
2.6.1 Signal inputs and amplification
The ATR19 hosts 3 or 4 DLATR boards. Each board has two independent channels for amplification and timing
discrimination. Each differential amplifying stage has 100 Ω impedance (2x50 Ω to ground) and a selectable differential
amplification gain between 20 and 100. The gain can be adjusted by a potentiometer (“poti”) on each board and channel
independently through holes in the top lid of the
ATR19 module.