GEM Chamber 20x24 prototype

The Gas tight box.
The box is realized in G10 with a total dimension of 30x30 cm^2.
In the picture are visible the green plane with the readout pads glued on the box. It is partially visible also the box cover.

The Gem stretcher.

The 20x24 gem is stretched with a tension of about 1Kg/cm.
The G10 frame is glued on top of the foil using the Ciba Epoxy 2010.

The Gem sag.

Several measurement have been performed with different loads trying to figure out the gem sag caused by electric fields.
With a field of 3 KV/cm the sag foreseen on a gem foil of 30x30 cm^2 stretched with a tension of 1Kg/cm is 10 micron that allows us to pile-up the gems without spacers.

The Gem is ready for the final assembling.
After 1h roughly the gem foil is released and extracted from the stretcher. After the edges cutting the frame is ready for the final assembling.

The Gem assembling.
The frames with the gem are piled up and assembled on the box with several teflon screw.
The gem hv contacts are solderd on the hv distributor card.
In the picture is visible the final cathod frame.

The hv distribution.
The gem foil is divided in 6 sectors.
Each sector is connected to the High Voltage through
a 1 Mohm resistor.


F.M.  Last Updated on 13-Mar-2002