| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a compact and simple shutter of a radiation thickness measuring device which reduces impact at a position stopping rotations of a rotary solenoid, suppresses bounding of the shutter, and extends a life.SOLUTION: A shutter driving portion 5 includes: a rotary solenoid provided so as to have an axial direction of a rotation shaft 5a1 of the rotary solenoid 5a in a vertical direction; and a shutter holder plate 5b fixed to a rotation shaft in a horizontal state orthogonal to an axial direction of the rotation shaft, and fixed with a lead plate 5c ot a thickness reference sample plate at one end. A shutter control portion pulse-duration modulates an excitation power source to the rotary solenoid during a fixed time period from a predetermined speed-reduction start position to a rotation finish position, and suppresses impact to a fixing portion of the lead plate or the thickness reference sample plate fixed to the shutter holder plate and the rotation shaft, at a position where the rotations of the rotary solenoid stops.</p> |
