マイクロメッシュを用いた 三次元電場構造型 μ-pic の開発
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マイクロメッシュを用いた 三次元電場構造型 μ-PIC の開発. 神戸大学 越智 敦彦、本間康浩、桂華 智裕、 故島陽太、守谷健司、道前武. 1. Introduction 2. Test operation of prototype 3. Summary. 日本物理学会 2007 年春季大会 26 Mar. 2007. Introduction. Mesh. 400 m m. Micro pixel chamber ( m -PIC) Position resolution ( - 100 m m) - PowerPoint PPT PresentationTRANSCRIPT
マイクロメッシュを用いた三次元電場構造型 μ-PIC の開発
1. Introduction2. Test operation of prototype3. Summary
神戸大学 越智 敦彦、本間康浩、桂華 智裕、
故島陽太、守谷健司、道前武
日本物理学会 2007 年春季大会 26 Mar. 2007
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
be attained safely• 104-5
• Reduction of positive ion distribution across detection volume– ~ 1% (simulation)
Applications
• Replacement of -PIC with GEM– Real time imaging device for
• X-ray• Gamma-ray• Charged particle• Neutron• etc.
• TPC– Low ion diffuse
• No gating method needed
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 mounted 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– Gain of 2 x 104 were attained
• With prototype mesh (distance is about 300m)
– More studies are needed for tuning up the parameters
• Simulation studies Keika will talk
Future prospects
• How to hold the mesh on detector?– How to keep the flatness of the mesh?– Wire or leg?– Insulations are attached with micro mesh or -PIC?
• Optimization of geometries and operation voltage?– Collection efficiency ↑ and gas gain ↑– To get consistency of simulation and measurement
• 2 dimensional readout and larger detection area– With amplifiers and data acquisition system
• We have to get the budget for this project !!!– There is no budget about this project yet !!
• We need more than 5M JPY to make new design of -PIC