Shutter head unit
Shutter Head Unit
The shutter head uses a rotary solenoid to flip a Supermax coated Silicon mirror in and out of the beam.
When the shutter is closed, the beam is reflected onto a water-cooled beam dump. When open, the beam passes straight through the unit. The open position is the electrically activated state of the solenoid.
Therefore, if the power were to fail, the shutter will close (a spring provides the force). LEDs on the shutter head indicate the status: red for open and green for closed. The open and close positions are detected by
Power is provided via the 9-pin D plug connector and open/close status can also be monitored via this connector. An optional Laser Shutter Controller, LSC01, supplies power and monitors the status of the
Note that the shutter is intended as a safety shutter and not for brief timing exposures. Using the LSC01, typical opening and closing times have been measured at 30 and 60 msec respectively (as defined by the period in which neither limit switch ‘sees’ the mirror). Note that these times cannot be equalised due to the solenoid limitations. The clear aperture is 19mm.
The beam dump is water cooled via the connectors (6/4 M6). For a water temperature rise of ΔT °C and a laser power P Watts, the water flow rate should be 0.014P/ΔT litres/min. e.g. for a 10° rise in water
temperature and 500W, the flow is 0.7 litres/min.
The shutter heads are provided with retractable screw rings for mounting to beam pipe. Before installing the shutter, check that the beam is centred to the beam pipe. Also note that there is an input and output side. Sending the beam in from the wrong side will cause it to hit the rear of the mirror mount.
The shutter will operate in any orientation.