Upload
anastasia-hall
View
221
Download
2
Embed Size (px)
Citation preview
マイクロメッシュを用いた高増幅率型 μ-PIC の開発
Development of -PICusing micro mesh
1. Introduction2. Test operation of prototype3. Simulation studies4. Summary
神戸大学 越智 敦彦、桂華 智裕Kobe Univ. Atsuhiko Ochi, Tomohiro Keika
400m
Mesh
Introduction
• Micro pixel chamber (-PIC)– Position resolution ( - 100m)– Timing resolution ( < 100ns)– High rate capability
( > 107c/sec/mm2)
• With micro mesh– Higher gain in stable
operation (>104)
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
Applications
• Replacement of -PIC with GEM– Real time imaging device for
• X-ray• Gamma-ray• Charged particle• Neutron• etc.
• TPC– Low ion diffuse
Prototype test• Micro mesh was mounted on -PIC
– Supported by plastic film / nylon wire• Support structure is future tasks
– Distance between -PIC and wire• About 300m
– Micro mesh is connected to HV controller
• Operation gas– Ar:C2H6 = 90:10
0.5mm
Micro scope picturesfor same place(different focus point)
Micro mesh mount on -PIC by hand.Size of -PIC = 3cm x 3cm.Efficient area using mesh = 2mm x 3cm
Test parameters
• Only signal pulses (gain) were measured– Gain dependency on
• Anode voltage (=Va)• Mesh voltage (=Vm)• Drift voltage (=Vd)
10 m
10 m100m
Drift Plane
Cathode
Anode 信号
Vd
Va
MeshVm
0
2000
4000
6000
8000
10000
12000
14000
16000
420 430 440 450 460 470 480 490 500
no meshVm=0VVm=-50VVm=-100VVm=-150V
Gain curve (Va, Vm dependence)
• Vd-Vm = 100V (Vd=2kV for no mesh plot)• Gas: Ar(90%)+C2H5(10%)• Source: Fe55 (5.9kV)
Va [V]
Gain
Collection efficiency problem
• Collection efficiencies for electrons– Depend on Vd-Vm … smaller is better
Without MeshWith mesh (Vm=0V)
Va=450V Va=450V
Vd [V] Vd [V]
Gain Gain
Current status of development
• Came up with the new idea -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 !!