We present below the specifications obtained on calculations performed at CREST Center for the hybrid mesh material, which suppose to be used in the micromegas nuclear detector. The concept of the micromegas was proposed in I. Giomatarios et al, Nucl. Instr. Meth. A 376 (1996) 29. Recently the description of ”bulk” version of the detector was published I. Giomatarios et al, Nucl. Instr. Meth. A 560 (2006) 405. Figure 1. shows a typical wire mesh.
Figure 1: The picture of wire mesh.
The main problem of the micromegas is significant dead time associated with the discharges between the mesh and anode of the detector in the case of sparking. We are proposing a hybrid mesh, which will allow to construct detector free from that problem.
The hybrid mesh has two types of thread. The first one is made from stainless steel as always in micromegas. The second wire must be non-conductive fiber, e.g. the glass or quartz fiber. It could be made of a nylon of a kapton fiber. The possible parameters are shown in the Table. The “Mesh per inch” could be different in two directions. Preferable pitch doe the SS wire is of 80 μm and the pitch for the non-conductive fiber is of 120-200 μm.
Table 1: Options for parameters of the experimental hybrid mesh.
The amount of the mesh required for detector testing is small, about 5-20 squire feet will be sufficient.