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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Time properties of MPGD signals

• Fast raising time

• Signal duration depends

on the way of energy

deposition

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Time properties of MPGD signals

• Fast raising time

• Signal duration depends

on the way of energy

deposition

– Particle identification by

time cut

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Time properties of MPGD signals

• Fast raising time

• Signal duration depends

on the way of energy

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