Methods of treating of stannous oxide particles having at least a partial surface crust of stannic oxide by contacting the particles with a reducing agent for a period of time sufficient to produce stannous oxide are provided. The invention also relates to the process for manufacturing the plate and to the device that includes said plate. Four equidistantly spaced raised portions are homogenously joined to the tubular ring. The light detection is relatively fast, whereby the gain profile variations are compensated by fast controlled variable optical attenuator and pump power adjustment upon the change in loading conditions. The instrument module includes an inner housing shell, at least one motor disposed within the inner housing shell, a control board being in electrical communication with the at least one motor, and an energy source being in electrical communication with the at least one motor and the control board. The CPE reports a result to the management device.