Document type:
Title:
Revision date:
Revision:
User's Manual (MUT)
Mod. N968 Spectroscopy Amplifier
14/06/2004
4
NPO:
Filename:
Number of pages:
Page:
00100/03:N968x.MUTx/04
N968_REV4.DOC
14
9
2.6 Front panel displays
PZ VISUAL INDICATOR:
PZ Visual Indicator leading to high precision adjustment of the
pole-zero cancellation, for exact compensation of the decay
time of the preamplifier signal. Left LED signals
overcompensation, right LED under compensation. Setting the
BLR switch to the adjust position activates the PZ Visual
Indicator. Under compensation can be corrected by turning the
potentiometer clockwise, while over compensation requires the
potentiometer to be turned anti-clockwise. A correct Pole Zero
setting is signalled by the two LEDs off (or, at least, blinking
low).
2.7 Input/Output connections
INPUTS:
INPUT
BNC front- and rear-panel connectors, accept either positive or
negative pulses with rise times of 10 to 500 ns and decay times of 40
µs to infinity;
if Preamp Gain = 1, Z
in
≅
1000
Ω
DC-coupled /
≅
500
Ω
AC-coupled;
if Preamp Gain = 0.1, Z
in
≅
1000
Ω
DC-coupled / AC-coupled
linear maximum: 1V (Preamp gain = 1, Amplifier gain = 10), 10 V (x01
attenuation selected); absolute maximum: 10 V.
Front-panel INPUT is provided with a test point.
RTP
(Rise Time Protection)
Rear-panel BNC connector (TTL signal,
50
Ω
impedance), it is provided by the Multichannel Analyzer (MCA) to
communicate to the amplifier that the ADC lower level threshold is
exceeded and the signal has been accepted. It is used only in the Live
Time Corrector (LTC) circuit.
PRS
Reset signal on the Rear-panel D-type 9 pin female connector.
OUTPUTS:
UNI
Front-panel BNC connector with Z < 0.5
Ω
and rear-panel
connector with Z = 93
Ω
; short-circuit maximum duration: 10 s (Front-
panel), ? 8 (Rear-panel); full-scale linear range of 0 to +10 V; active
filter shaped; DC-restored; DC-level adjustable to ±100 mV.
Front-panel UNI output is provided with a test point.
BI
Front-panel BNC connector with Z <1
Ω
and rear-panel connector
with Z = 93
Ω
; short-circuit maximum duration: 10 s (Front-panel), ?
8
(Rear-panel); prompt output with positive lobe leading and linear range
of ±10 V; active filter shaped.
Front-panel BI output is provided with a test point.
CRM
Rear-panel BNC connector with Z <10
Ω
provides a nom5
V, 100 ns logic pulse every time the input signal exceeds the baseline
restorer fast
discriminator threshold.
INH
Rear-panel BNC connector with Z <10
Ω
provides a nominally
+5 V logic pulse (suitable for the MCA anticoincidence input) when the
internal pile-up rejection logic detects a distortion of the input signal due