Time properties of MPGD signals - jlab.org · 2015/8/3 MPGD@LZU 4 Time properties of MPGD signals •Fast raising time •Signal duration depends on the way of energy deposition

Time properties of MPGD signals —— MPGD studies in Lanzhou university

Yi Zhang

2015/8/3 MPGD@LZU 2

Contents

• Time properties of MPGD signals

• MPGD studies in Lanzhou university

• future plan

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Time properties of MPGD signals

• Fast raising time

– No inductive signals in

drifting

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• Signal duration depends

on the way of energy

deposition

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deposition

– Particle identification by

time cut

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deposition

– Particle identification by

time cut

• The maximum duration is

independent of incidental

energy

– Correct the initial position

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To demonstrate the conclusions, a test was done

@ IMP

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55Fe spectrum, just to check the measured signal

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Got the expected result

normalized

Mean=135.7 σ= 22.8

Mean=89.4 σ= 1.744

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Got the expected result, but also issues

归一化

Mean=89.4 σ= 1.744

Mean=135.7 σ= 22.8

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New version of the detector

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Garfield++ simulation of the double GEM (as a reference)

Edrift=1kV/cm

EGem=58.33kV/cm

gain=9032

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Garfield++ simulation of the double GEM + Mesh

Edrift=1kV/cm

EGem=58.33kV/cm

Eamp=40kV/cm

gain=68930

Schematic view of fast neutron imaging

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neutron

collimator

proton

PCB

metallic mesh

polyethylene

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Challenge of DAQ for offline analysis (18×10 cm)

8(bit)×50MHz×1700(channel) = 79.162 GB/s

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Signals collected on the PCB plane

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Steps of online track reconstruction

• Divide signals according time —— time slide

– Segmentation in readout plane —— cut on signal amplitude

– Combine adjacent segment —— identify clusters of hits

• Process multi time slides

– Combine adjacent time slides —— distinguish if signal continues

– Integrate multi time slides —— identify the start and end of a

signal

Forming hit clusters in one time slide

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Combine few time slides, get the complete tracks

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Identify the tracks

Simulation with Quartus II (FPGA development)

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Signal ID

charge

Cluster sum X,Y position

Participate the update of APV25 readout panel

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old new

@ JLab

Improved signal/noise ratio

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Old panel,

RMS of noise

~16.89

New panel,

RMS of noise

~6.99

Reduced ~60% noise

@ JLab

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5米

10米

15米

Observed an increase of

noise with longer cable

Help from INFN

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The 5th CMPGD workshop @ LZU Jul 23-24, 2015

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Future plan

• Detector —— build a hybrid MPGD

– Gain, rising time, spark

• DAQ

– Simulation + test on develop board

– Design of the peripheral circuit

• Way of signal readout

– Position encoding

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Thanks for your attention

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BACKUP

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Future application I

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Future application II

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nuclear material thermal neutron

fast neutron

PC

B

poly

eth

yle

ne

the γ spectrum

Key parameters in simulation

material

� PCB ：FR-4(Si、C、H、Br、O) 1.5mm

�Working gas： Ar(75%)+CO2(25%) drift 2cm

� mesh: steel 100um thick 40% geometric transmission

� polythene： 300um thick

Energy of hot neutron 30keV～70keV

Energy of fast neutron 0.8～3.3MeV

Time properties of MPGD signals - jlab.org · 2015/8/3 MPGD@LZU 4 Time properties of MPGD signals •Fast raising time •Signal duration depends on the way of energy deposition

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