MSI-8(data sheet V2.0_01)

8 channel preamplifier+ shaper + timing filter amplifier

mesytec MSI-8 is a compact 8 channel preamplifier shaper box with integrated timing
filter amplifieres. Due to the modular setup, preamplifier and shaper module types can beselected individually for each channel. MSI-8 is the ideal solution for setups with a mix ofdifferent detectors requiring individual bias supply and energy ranges. It is also well suitedfor moderatly segmented strip detectors or as an easy to use and flexible lab system.

Features:• 8 channel compact standalone module• Preamplifier and shaper modules
individually selectable• Shaper with baseline restorer• Two shaping times, jumper selectable• Integrated timing filter amplifier• Individual and common timing output• Single and common detector bias
• All outputs can be terminated with 50 Ω
• Lemo connectors for in- and outputs• Discriminator gate output for peaksensing ADC

Schematics:

mesytec GmbH & Co. KG
Wernher-von-Braun-Str. 1, D-85640 Putzbrunn, Germany
phone: +49 - 89 / 456007-30 fax: +49 - 89 / 456007-39
info@mesytec.com - www.mesytec.com

MSI-8

8 channel preamplifier shaper box

System Design
MSI-8 has a very flexible modular design. Preamplifiers and shaper, timing filter amplifiers are pcb modules
mounted on a common main board. They can be chosen individually for each channel. This gives maximum
flexibility for multi channel setups with different detectors.

Rear Panel

Preamplifier inputs

Common bias switches• Lemo connectors directly situated on thepreamplifier modulebias inputs (not the detector inputs!) with switch„on“ are connected with each other.
This allows bias supply with a single lemo connector plugged to one of the connected bias inputs.
E.G. for strip detectors, switch all bias inputs to„on“ and connect bias voltage to one bias input.

Detector bias

• Lemo connectors directly situated on thepreamplifier module
Pulser input• Tail pulse, or square pulse• Internally terminated with 50 Ω
• 5 V for maximum output voltage at
minimum gain
mesytec GmbH & Co. KG
Wernher-von-Braun-Str. 1, D-85640 Putzbrunn, Germany
fon: ++49 - 89 / 456007-30 fax: ++49 - 89 / 456007-39
info@mesytec.com - www.mesytec.com

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MSI-8

8 channel preamplifier shaper box

Front Panel

Shaper outputs

•
•
•
•

Lemo connector
Positive, gaussean pulse
Max 10 V (8 V at 50 Ω)
Two jumper selectable shaping times(standard is 1 us FWHM and 2 us FWHM)• Supply voltages(currents for box with 8 shapers and 8 preamps)+12 V
250 mA
+6 V
50 mA
–6 V
–170 mA
total power: 4.3 W

Timing output• Pin connections(numbers are noted on the connector):• Lemo connectors• Fast negative signal• Max –1 V

pin

name

pin

name

1

Gnd

6

Not connected

2

Gnd

7

Not connected

3

+6 V

8

Not connected

Differential preamp outputs

4

+12 V

9

Not connected• 20 pin standard connector• 8 differential preamp signals• Can be connected to a twisted pair cable andterminated with 100 Ω• Amplitude: ±1 V for maximum range

5

–6 V

Common timing• Gain can be adjusted by a factor of 10• Another factor 5 by preamp sensitivity switch(at the preamp module)

Gate output and gate threshold adjust

Box size

length = 170 mm
width = 105 mm
height = 67 mm• NIM signal output• Useful for gating an external peak sensing ADC
in lab tests. As long as one of the shaper outputs
exceeds the threshold voltage, the NIM-output
gets negative.
Power supply• SUB-D 9 female connector. (NIM convention)mesytec GmbH & Co. KG
Wernher-von-Braun-Str. 1, D-85640 Putzbrunn, Germany
fon: ++49 - 89 / 456007-30 fax: ++49 - 89 / 456007-39
info@mesytec.com - www.mesytec.com

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MSI-8Preamp Module (MMPR-1)

8 channel preamplifier shaper box

2 us:

low noise, for low rate applications, very
well selected strip detectors.
Standard detectors often have a lot of 1/fnoise resulting in better noise to signal
ratio with shorter shaping time.
1 us: standard, best for large Si-detectors,
standard strip detectors
0.5 us: optimized for high countrates
0.25 us: optimized for very high countrates>100 kHz, use fast ADC!

Input

• The standard preamplifiers can handle capacitysof up to 1000 pF
Detector bias

• Maximum bias voltage: ±400 V• Bias filter 10 MΩ / 50 MΩ
(selectable by internal jumper)• Baseline shift with frequency:• A passive baseline restorer is integrated• For 1 us shaping time and a rate of 100 kHz,the baseline shifts less than 100 mV (1 %)• DC Offset at shaper output: U <10 mVPole zero adjust:• Modules are adjusted to less than 20 mV of undershoot at the shaper output• You can readjust if necessary

Power consumption• Low power: typ 150 mW• cooling not necessary

Timing Output

For details see data sheet of MMPR-1

Shaper Module (MMSH-1)
The module includes a shaper with passive
baseline restorer, an output driver for 10 V (8 V @50 Ω) and a timing filter stage with timing output.
The jumper allows to select one of the two
shaping times.

• Timing filter amplifier(is included on the shaper module)• integration: 7 ns
• differentiation: 200 ns• Noise:N = (70 + CDet) * 0.35
CDet = cable + detector capacity, in pF;
N = noise FWHM in keV;
Power consumption

+12 V
10 mA
–6 V
10 mA
total power = 180 mW
Connector(left pin = 1)
pin

name

pin

name

1

gnd

6

+12 V

2

in+

7

gnd

Shaper Output

3

in–

8

out shaper• Filtering: quasi gaussean (CR(RC)5)• Shaping time (FWHM):

4

gnd

9

out timing

5

–6 V

10

gnd

For details see data sheet MMSH-1

mesytec GmbH & Co. KG
Wernher-von-Braun-Str. 1, D-85640 Putzbrunn, Germany
fon: ++49 - 89 / 456007-30 fax: ++49 - 89 / 456007-39
info@mesytec.com - www.mesytec.com

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MSI-8

8 channel preamplifier shaper box

Timing considerations
Best timing

With constant fraction discriminator• Use high bias voltage to geht maximum charge
carrier velocity in the intrinsic zone of thedetectors• Implant particles with low range on the p-side(=strip side or guardring side for 2 sided
detectors)!

• fraction = 0.25, delay = 15 ns• timing is 25 % worse, but walk correction is
intrinsic

Time resolution with leading edge
discriminator• Use a low threshold to minimize walk
• If you have a wide range of input amplitudes,
use shaped signals for walk-correction• If the signal is much alrger than the noise, thetiming resolution t can be estimated: t  20ns * N ;SCommon timing output• For low energies (<10 MeV) about three times
worse than single channel timing (noise increased by √8)• For higher energies
Noise is not the limiting factor. If a coincidencewith responding energy channels is used insoftware, the 8 channels can be calibrated withindividual timing offset parameters.
If there is no coincidence, the timing
information will not get bett than 0.5 ns ue todelay tolerances for the 8 channels.

N = noise [MeV]
S= signal amplitude [MeV]• For 100 pF detector + cable capacity and1 MeV signal this means a timing resolutionof t = 1 ns
• Timing resolutions better than 100 ps are
difficult, even for large signals

mesytec GmbH & Co. KG
Wernher-von-Braun-Str. 1, D-85640 Putzbrunn, Germany
fon: ++49 - 89 / 456007-30 fax: ++49 - 89 / 456007-39
info@mesytec.com - www.mesytec.com

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