| 摘要 |
In order to measure the weight per unit surface area of a continuous web of paper (10), the invention calls for a radioactive source (16) to be mounted on one side of the web (10) and a semiconductor detector (20) in the form of a linear photodiode array to be mounted on the other side. The detector array (20) is moved, together with the radioactive source (16), across the web of paper (10) at right angles to the direction of motion of the web and, in addition to measuring the current from each individual photodiode, the currents from the photodiodes at particular positions across the web are recorded. |
