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
10
to pile-up. Signals whose peak occurs when the INH signal is active
must be thus rejected.
BUSY
Rear-panel BNC connector with Z <10
Ω
provides a +5 V logic
pulse for the duration that the input pulse exceeds the baseline restorer
discriminator.
LTC
Rear-panel BNC connector, provides a positive true TTL logic
signal that is used to stop the MCA time counter; this allows a precise
evaluation of the source actual rate.
PREAMP POWER
Rear-panel D-type 9 pin female power connector; it
mates with captive and noncaptive power cords on almost all
preamplifiers. Contact assignment is shown in Fig. 2.1.
2.8 Technical specification table
Table 2.2: Mod. N968 Technical Features
Packaging
One unit wide NIM unit
Gain range
1 ÷ 3000
Pulse shape
UNIpolar shape
: quasi Gaussian, peaking time 2.4 Ts, pulse
width at 0.1% level equal to 2.9 times the peaking time
Bipolar shape
: approximate derivative, time to crossover 3 Ts
Integral non linearity
<± 0.025% @ 2 µs shaping time
Temperature instability
(0 to 50°C)
Gain
: < ±50 ppm/°C.
DC level
: UNIpolar output: < ±10 µV/°C
BIpolar output: < ±30 µV/°C
Bipolar crossover walk
≤
±3 ns at 2 µs Ts for 50:1 dynamic range
Overload recovery
Recovers to within 2% of rated output from X300 overload in 2.5
nonoverloaded pulse widths using a gain of 1000 for UNIpolar
Output. Same recovery from X1000 overload for BIpolar
Spectrum broadening
Typical: <16% FWHM for a
60
Co 1.33 MeV gamma line at 85% of
full scale for an incoming count rate of 10
3
to 10
5
counts/s
(Unipolar Output, 2-µs shaping)
Spectrum shift
Peak position typical shift: <0.024% for a
60
Co 1.33 MeV gamma
line at 85% of full scale measured from 10
3
to 10
5
counts/s
(Unipolar Output, 2-µs shaping) (T.B.C.)
Equivalent noise
4 µV / 6 µV (RMS) for UNIpolar/Bipolar output for 3 µs shaping time
and coarse gain = 100
3.5 µV / 5 µV (RMS) for UNIpolar/Bipolar output for 3 µs shaping
time and coarse gain = 1000
[Fig. 2.3: Equivalent RMS Noise Vs. Shaping Time (Ts)]