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1
?????????????????µ-PIC???Development of
m-PICusing micro mesh
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Kobe Univ. Atsuhiko Ochi, Tomohiro Keika

• 1. Introduction
• 2. Test operation of prototype
• 3. Simulation studies
• 4. Summary

2
Introduction
Mesh
400mm

• Micro pixel chamber (m-PIC)
• Position resolution ( - 100mm)
• Timing resolution ( lt 100ns)
• High rate capability ( gt 107c/sec/mm2)
• With micro mesh
• Higher gain in stable operation (gt104)

3
Effect using micro mesh

• Higher Electric field around the anode
• Vertical direction against detection flat
• Without increase of e-field near cathode edge
• ? Higher gas gain will attain safely
• Reduction of positive ion distribution across
  detection volume

4
Applications

• Replacement of m-PIC with GEM
• Real time imaging device for
• X-ray
• Gamma-ray
• Charged particle
• Neutron
• etc.
• TPC
• Low ion diffuse

5
Prototype test

• Micro mesh was mounted on m-PIC
• Supported by plastic film / nylon wire
• Support structure is future tasks
• Distance between m-PIC and wire
• About 300mm
• Micro mesh is connected to HV controller
• Operation gas
• ArC2H6 9010

6
Micro scope pictures for same place (different
focus point)
0.5mm
Micro mesh mount on m-PIC by hand. Size of m-PIC
3cm x 3cm. Efficient area using mesh 2mm x 3cm
7
Test parameters

• Only signal pulses (gain) were measured
• Gain dependency on
• Anode voltage (Va)
• Mesh voltage (Vm)
• Drift voltage (Vd)

Drift Plane
Vd
Mesh
Vm
10 mm
Cathode
100mm
10 mm
Anode
Va
8
Gain curve (Va, Vm dependence)
Gain
Va V

• Vd-Vm 100V (Vd2kV for no mesh plot)
• Gas Ar(90)C2H5(10)
• Source Fe55 (5.9kV)

9
Collection efficiency problem

• Collection efficiencies for electrons
• Depend on Vd-Vm smaller is better

Gain
Gain
Va450V
Va450V
Without Mesh
With mesh (Vm0V)
Vd V
Vd V
10
Current status of development

• Came up with the new idea
• m-PIC with micro mesh
• Prototypes were made and tested
• Gas multiplicity of it is more than 3 times
• More studies are needed for tuning up the
  parameters
• Simulation studies
• ? Keika will talk
• There are many issue to study
• How to hold the mesh on detector?
• Optimization of geometries and operation voltage?
• 2 dimensional readout and larger detection area
• We have to get the budget for this project !!!
• There is no budget about this project yet !!