Real-time X-ray beam position monitor for synchrotron beamlines
The RIGI is a 4-quadrant beam position monitor suited for hard X-ray synchrotron beam lines. It is ultra-high-vacuum (UHV) compatible, can remain continuously in the X-ray beam and allows monitoring the position of the X-ray beam in real time with a sub-micron precision. The RIGI is available with two different active areas to fit into most beamlines and is very simple to install and to operate.
Principle:
The RIGI is based on a very thin CVD diamond membrane. The transmission of the X-ray beam generates charge carriers in the diamond layer and hence a photocurrent is induced. With an external picoampere meter, this photocurrent can be measured for each pad. The difference of photocurrent between pads over the total current gives the signal, which can be calibrated to provide position information.
Applications:
- Beam intensity monitoring after monochromator
- Automatic beamline alignment after change of diffractometers
- Online feedback
- Pink beam monitoring
Technical specifications
| Sensor | CVD diamond membrane |
| Sensor thickness | 12 µm |
| Transmission | > 98% at 10 keV |
| Framing rate | ~1 kHz (depends on read-out setup) |
| Bias voltage | typ. -10 VDC |
| Large area RIGI 4-M | |
 Pad size |
4.5 x 1.5 mm |
| Gap between pads |
20 µm |
| Total active area |
9.0 x 3.0 mm |
| Window size |
9.6 x 3.6 mm |
| Small area RIGI 4-S | |
| Pad size |
2.0 x 1.0 mm |
| Gap between pads |
6 µm |
| Total active area |
4.0 x 2.0 mm |
| Window size |
4.6 x 2.6 mm |
| Cooling | Not required |
| Dimensions | 40 x 30 mm |
| Weight | ~ 3 g |