Manual for the new rotational fast shutters (FS2 @ BL and FS3 @ PG)
The new rotating fast shutters are able to select single pulses (or pulse trains if in multi-bunch mode) out of the generic 10 Hz repetition rate of the FLASH machine.
The rotating shutter consists of a thin aluminium (forseen was glassy carbon) disk which contains an outer trace with 6 equidistant slits. The disk is driven by a DC-motor outside the vacuum. A magnetic rotary feedthrough carries the motion of the motor into the vacuum. A programmable logic controller (PLC; programming done by Jan Tolkiehn) is used to control the system including a low-voltage DC-motor with rotary encoder and a planar light barrier. To pass a pulse through the shutter, the motor is triggered to rotate when one pulse hits the shutter. During the following 100 ms, the motor rotates the shutter disk by 30°, leading to a movement to the fully open position, thus allowing the passage of the following pulse. During the next 100 ms the rotation is continued to the 60° position, thus blocking the next pulse by turning the disk to the fully closed position.
Contents:
- Manual for the new rotational fast shutters (FS2 @ BL and FS3 @ PG)
Details
- able to open/close within 100 ms
- uses machine bunch train trigger (10 Hz) to sync with the machine
- feedback on angular motor position and light barrier signal available
- simple open/close mode and feeback signals (via DOOCS, jddd-Panel)
- open/close mode, single shot mode, chopper mode, direct control of angular position, and feedback signals (via LabVIEW from the hasfuser03 PC)
- external single shot trigger mode (via TTL or 5V signal, over the patchpannels)
- trigger signal when fast shutter is open available at beamline crates (event E0 for BL shutter, event E1 for the PG shutter)
Design and setup
- FS2_3 3D CAD drawing:
- Design details:
- chopper wheel (aluminium, thickness:0.5 mm): diameter 182 mm, 6 equally distributed slits with an opening angle of 18° and a slit depth of 38 mm (-> slit width in the middle: ~22.7 mm)
- CF200 flanges
- magnetic rotational feedthrough (MD35 from Vacom)
- DC motor (Maxon RE40 with GP42 planetary gearing)
- laser light barrier: beam size: width 35 mm; height: 2 mm; detector output: 0-10 V
- Shutter FS2 (BL branch) is located directly in front of the old shutter FS1 and behind the VLS mirror chamber in the BDA area.
- Shutter FS3 (PG branch) is located behind the PG0-M1 mirror chamber in the BDA area.
Controls
- SPS control details:
- FS2(BL): hasffs02 (131.169.38.74), connected to network jack: 28c-Halle-105-L (location: BDA area, on the right side, at the PETRA III ring wall)
- FS3(PG): hasffs03 (131.169.38.77), connected to network jack: 28c-GalRack1-3-L (location: rack gallery)
- Both SPS are located beneath the shutters in the BDA area
