MDLL(Data sheet V1.5_01)

Readout Systemfor Delay line Detectors

mesytec MDLL is a delay line readout system for multi wire proportional counters with twodelay lines. The position is determined from the delay of the signals from the two ends ofa delay line. An anode signal is needed to start the signal processing. It includes discrimi nators (CFDs) and so allows direct processing of detector signals after amplification(input level –1 V).
Features MDLL:• X and Y position calculation• Anode amplitude is converted and availablefor adjustment• Register adjustable to detector delays
from 100 ns to 500 ns• List mode with time stamped events(100 ns resolution)• Stand alone and NIM form factor• In NIM case: can be time synchronized with several
MDLL modules and mesytec MCPDs (neutron systems)• Accepts –1 V analogue detector pulses, rise time typ.
10 ns to 35 ns.
(CFD- delays can be selected with jumpers)

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

MDLL

MWPC readout system

Technical Data
Input stage

TAC section• 5 inputs:

MDLL has 4 TACs (time to voltage converters)
which are started by the anode signal and are
stopped by the X0, X1, Y0, Y1 signals.
The range of the TACs is software adjustable from
100 ns to 500 ns.

X0, X1 for first coordinate delay line,
Y0, Y1 for second one
Anode input for common signal.
•Galvanic separation•

Accepts negative input of max –1 VInput filter

Time constants: see Table

Power consumption: (max 7 W)

+6 V 1 A–6 V –200 mA(at power up max 2 A)

For stand alone modules:
The ripple should be less than 50 mVpp
at 50/ 60 Hz.

CFD Discriminator• CFD delays, standard isFor Cathode:8 ns, 11.5 ns, 15.5 ns, and 19.5 ns,
For Anode:
9.5 ns, 14 ns, 19 ns, 28 ns
Delays are jumper selectable. Shortest delay
when jumper is near to bottom.
• Fraction 40• Threshold adjustable via software.
Maximum value 255 is –1 V
(maximum threshold). Default: 20 = 4 n%.

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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MDLL

MWPC readout system

Adjustment of MDLL module for
MWPC
Preparations

Connect detector to the MDLL module (inputs
X0, X1, Anode, Y0, Y1). All signals negative,
Amplitude typically –1 V, rise time 40 % (= fraction) to maximum 10 ns to 15 ns.
Set CFD-delay via jumpers for 5 inputs.
Install the Detector and add a source to fill all theactive area of the detector.
Apply typical voltages to the detector.

Adjust timing range and offset(spectrum spread)

1. Open 2-D (XY) view
2. Vary the spectrum spread X, Y (reasonable values 20...60)
3. and shift X, Y (range0...256) to fill all the 2-dspectrum
Well adjusted 2-D views

The input LEDs should light up.

Basic adjustments
Set parameters to adjustment defaults:
1. Open Set MDLL window
2. Set low thresholds for discriminators X, Y, andAnode to value 20
3. Set X,Y spread to 40 and X, Y offset to 100
4. Open timing and Energy restrictions
Energy: (minimum = 10, maximum = 240),
Timing: low 100, high 1000
5. Click Spectrum „E, X, Y“
6. Click „apply“
countsStart Data acquisition. → event counter should increment.
After activating the set command the spectra
should be cleared with the „clear“ button to see
the new data.

Adjust Amplitude
1. Spectrum: click „Energy“
2. Adjust Detector Voltage for correct output
amplitude. The amplitude range can be from 0
to 240, the spectrum should not be cut off significantly at the upper edge (240)amplitude

Energy spectrum
18000
16000

c o u n ts

14000
12000
10000
8000
6000
4000
2000
00240

480

720

960

Amplitude

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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MDLL

MWPC readout system

Add restrictions to the data (data filter)

The restrictions help to reduce the background.
They are not essentially needed for first tests.
If you change any other parameter after the restrictions are set, the efficiency may decrease or
all data may be filtered off. So when changing
other parameters, the restrictions should be removed before (set timing and energy window toadjustment default).
Sum timing restrictions

1. Stop data acquisition
2. Open set MDLL window
3. Click “E, Xtsum, Ytsum”
4. Clear spectra and start data acquisition

The position X and position Y spectra now show
the timing sum of the X-coordinate delay line, andthe Y delay line. There should be a sharp peak ofabout 10 bins FWHM at about position 400 to500.
Now you can set the timing sum lower and upperlimits for X and Y coordinate via „Set MDLL“window. You can immediately see the effect in thespectrum.
Energy restrictions

If the MWPC provides a significant amplituderesolution, the energy restriction may make sense.
Fot neutron detectors, a lower cut off may improve the position resolution with cost of efficiency.

Overview, serviceable elements inside the box

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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