A cellulose acylate-based dope, which has an exothermic peak giving a calorific value of 1 to 10 Jg, between 0 and 40\xb0 C. The transmission expected value is a sum of expected transmission counts, which is a reciprocal of multiplication of forward transmission success rate and backward transmission success rate of a communication link between the nodes disposed on the transmission paths. The pivot joint coincides with the center of gravity for the X-ray imaging arm. Further, an intrinsically safe two-wire bus connecting the controller and the gauging units is provided, wherein the two-wire bus is usable both for transmitting measurement signals related to the sensed product parameters from the gauging units to the controller and for providing intrinsically safe power from the controller to the gauging units. The design preferably includes a provision for readily disabling the radiation resistant system so the same design can be easily transformed into a non-radiation resistant design. The edge portions of a lower auxiliary capacitance electrode and the terminal portion are sequentially coated with a first insulating film, a second insulating film that is thinner than the first insulating film, and a third insulating film.