Micro Pattern Gas Detector(MPGD) is a new type of radiation detector that works with gas to replace conventional wire chambers.

GEMを3段用いたガス増幅と2次元ストリップからの信号読み出しの模式図 ©Rey.Hori

Purpose and Vision

The project is aiming to promote a 2D micro-pattern gas detector technology for various fields as well as particle and nuclear physics experiments.


A gas electron multiplier (GEM) is a type of micro pattern gas detector (MPGD), in which incoming particles ionize the gas inside the chamber, producing electrons. An essential feature of all gaseous ionization detectors is the amplification of the resulting electrons by a factor of millions or more. GEM amplifies using a GEM foil perforated with arrays of small holes. Each GEM foil is a sheet of polyimide insulator sandwiched by thin copper electrodes. An electrical potential of 320 volts is applied across the GEM foil, producing inside each hole the strong electric field necessary to accelerate and cascade-multiply electrons.

Since the geometry of the GEM is flexible. each hole in the GEM foil can detect and amplify a signal. This means that the detector, together with the flexible geometry of the readout pad, can report two-dimensional information of any desired shape. In addition,the background noise of the GEM is generally low.

A new type of activity has started for the fundamental R&D work convened by the university researchers, where very basic properties or new structures/fabrication methods of MPGD are investigated.

Related WEB Site

MPGD group

Related Group

ASIC group
DAQ group
Kobe University μ-PIC group
Kokkaido University

Related Facilities

Hokkaido Unoversity 45MeV electron linac