MPR-16 / 32 / 64 -LOG
(Data sheet V8.0_01)

16 / 32 / 64 - foldlin/log charge
preamplifier

The mesytec MPR-LOG series provides a new type of multichannel preamplifier modules
which are specially designed for applications where very fast recovery from large signals
and precise spectroscopy of very small signals is required. They will usually be used for silicon strip detector readout. A typical application is decay spectroscopy after implantationof a heavy ion into a silicon detector. The MPR series can best be combined with the mesytec MSCF-16 shaping-/timing filter/ discriminator module.
Features:
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16 / 32 / 64 channel compact module
Sensitivity switch, 2.5 / 10 MeV linear
Recovers within 15 us from 3 GeV signals
ESD input protection
Differential output 100 Ω or
MPR16L with Lemo output connectors
Pulsar input
Bias voltage up to ±400 V
PCB module available for in vacuum use

Schematics:(for MPR-16)
ESDprotection

10 nGain
stage
1/5

Input

Diff.
Output...

15 furtherbranches

Diff.
Outputs

10 M

1MHV

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

multichannel lin/log
preamplifier

MPR-16 / 32 / 64 - LOG
Technical Data
Energy ranges

Output stage

The MPR-LOG series provides a linear range,
which covers 70 % of the total range. The last
30 % cover the range of up to 3 GeV.
A switch allows to choose a linear range of
2.5 MeV or 10 MeV.

• Differential output for twisted pair 34 pin maleheader connector.
• Output amplitude: ±1.3 V for maximum energy• Pin assignment of output connector:
pin 1, 2 channel 1, pin 3, 4 channel 2…..
pin 33, 34 output ground

With MSCF-16 the optimum gain setting(with gain jumper G2) is G = 2.2.

Rise and decay timeStandard decay times is 10 us.
Rise time is 12 ns for 0 pF input capacity.
Noise

N = (6.5 + 0.06/pF) keV [FWHM] for 2 us
FWHM shaping.
Temperature stability

10 MeV lin range with 2us (FWHM) spectroscopy
amplifier STM16+Input stage• Input connector(s): SubD25 female connector(for a 16 channel unit)• Pin assignment:Function
Sig-gnd
Cha 1
Cha 2
Cha 3
Cha 4
Cha 5
Cha 6
Cha 7
Cha 8connector Function connector
1,2,7,12,1
Cha 9
193,14,15,2511
Cha 10623
Cha 11
1810
Cha 12522
Cha 13179
Cha 14421
Cha 15168
Cha 16320guard ring24

• Positive and negative charge can be amplified
equally.
• The guard ring output (24) is connected via
R-C-R filter (100 kΩ, 10 nF, 100 kΩ) to thecommon detector bias input.

As MPR-16-log is based on diode current - voltage relation, the gain is slightly temperature dependent. Temperature coefficient in 10 MeV range at
5 MeV signal is about -3*10-3/K. So a thermallystabilized environment or permanent pulsar calibration (i.e. 1 pulse per second) is required forbest stability. Example: at environmental temperature variation of ±1 K the gain will change by±0.3 %. After power up, wait for thermal equilibrium before performing precision measurements.
Pulsar input

The pulsar is internally distributed to individual
charge termination capacities. Tolerances ±10 %Temperature stability 50 ppm.
MPR-16 log
0.78 pF (17 MeV/V)
Detector bias input• Lemo connector• Maximum voltage 400 V• When connected detector side must be on
ground level: terminate bias input with 50 Lemo terminator.

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

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MPR-16 / 32 / 64 - LOG
Ground connections• Ground screws on front and rear side• There are two different ground connections:
input and output ground.
• Input ground is connected to the vacuum
vessel if the setup is not isolated(ie. isolated flange).
• In critical environment the output ground canbe connected to the NIM electronics.

multichannel lin/log
preamplifier

STM16+ Shaper output for implantation anddecay signals(10MeV-lin range)

Power connector

SubD9 connector:• 1, 2 = gnd• 3= +6 V• 4= +12 V• 5= –6 VPin out of on board power connector
for PCB version••••••gnd :+12 V :
+6 V :–6 V :
LED+ :
LED– :

Shaper signal for implantation with energy of 3 GeV
followed by a decay signal of 2.5 MeV(The undershoot after implantation is artificial and dueto the tail pulsar)

1,3,10,11,1275
913 ("power ok" LED)
14Power consumption for 16 channels

Parameter+6 V–6 V+12 V
total power
HP-modeMPR-16-LOG
70 mA
60 mA
40 mA
1.3 W

Cooling

Due to the low power consumption cooling is notnecessary.
For in vacuum use: If several PCBs are densely
packed, heat conducting metal shields should beplaced in between the PCBs. Avoid to warm up
silicon detectors by the dissipated power.
Dimensions• Length• Width• Height

Implantation signal of 3 GeV. Red: preamplifier signal(before amplification of 2), blue: Shaper signal.
(Realistic signal, created with square pulsar): 173 mm (without connectors): 105 mm
: 46 mm (MPR-16),
67 mm (MPR-32),
92 mm (MPR-64)

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

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