PERFORMANCE INVESTIGATION OF MULTISTEP AVALANCHE CHAMBER

We have designed and operated a test module of multistep avalanche chamber with effective detection area of 9 by 9 cm². Argon-acetone mixture gas is provided by a simple gas mixing system, and mixture ratio can be modulated by gas flow. The performance of the chamber has been investigated by use of ⁵⁵Fe 5.9 keV X-ray source at acetone concentration in argon of 2.7％, and the effect of acetone concentration to the chamber has been measured.