Single rate plateau curve with different gas mixture Standard cell prototype with SLD gas mixture If we want a plateau region starting at lower voltage we need to increase Ar in our gas mixture. The plateau with Ar 16%, Isob 9% and CO2 75% has a plateau curve very similar to the one found for the 9x9 standard cell prototype with SLD gas mixture

I choose Ar/Isob/CO2 – 16/9/75 Rates are normalized by the number of HV channel. The plateau region is acceptable: ~ between 4.8KV an 5.2KV. All the tube has very similar behavior. Tube number 2 still has a cell which sparks frequently: this tube should be rejected.

Gas mixture: Ar/Isob/CO2 – 16/9/75 @ 5000V Signals from the scope Ch. 3 (yellow) phi strip signal (no amplified) – Ch. 4 (blue) wire OR signal (threshold 30 mV) Gas mixture: Ar/Isob/CO2 – 16/9/75 @ 5000V