The fast shutter used on ID23-1 is based on a fast stepper motor where the axis is fitted with a shaft drilled by a 2 mm hole for the X-rays going through. The 360 °rotation is completed by 12 steps.

ID23_eh1_fastshutter.gif

As we are very concerned about the quality check along the beamline, careful analysis has been carried out in order to provide the best diagnostic on this device. Especially on the opening and closing time of the shutter.

A 1 mm hole on top of the shaft have been drilled at 90 ° comparing the X-ray hole. This hole allow an infrared led and its detector to be fitted in order to check when the opening and closing command are sent the shutter does it.

Also, a scattering diode has been mounted just after the shutter to check the beam intensity. This diode is used for the translation alignment of the shutter (shutx and shuty).

The delay between the the command and the effective opening and closing of the shutter is pre-programmed and taken into account by an electronic card called MUSST controling the phi and the shutter. This card is also able to carry a full on-line diagnostic by collecting during the data collection passes: the i1 intensity (X-ray beam after the fast shutter), the phi position, the time, shutter command, Infrared sensor and the phi axis speed.

This diagnostic is saved in the user directory as prefix_runnumber_0diag.dat. It is an ascii file visible by using Newplot, graphical user interface to SPEC scan files. It is a freeware available on this ESRF intranet web address.