Study on the analog read-out of the YBJ-ARGO RPC

The YBJ-ARGO experiment is presently in the mounting and debugging phase at the Yangbajing High Altitude Cosmic Ray Laboratory, Tibet, China. The YBJ-ARGO EAS array is composed of bakelite RPCs which operate in the streamer mode. The digital read-out, performed by means of read-out strips, allows measuring the secondary particle number of small size air showers. To extend the dynamic range of the secondary particle number density up to 104/m2, thus to measure the component and spectrum of primary cosmic rays at the knee region, it is necessary to implement the analog read-out of the RPC, which is achieved by encapsulating each RPC with two Big PADs. This paper reports on the primary analysis of the analog read-out signal of the Big PAD under different gas mixtures, including the amplitude distribution and ratio of the single streamer signal