The exemplar presented here is mounted on a metal support acting as a case as well. It is painted black both inside and out and consists of a trapezoidal base on three sharply pointed feet, a side piece, a front plate and a lid, all 6 mm thick.
The grating is attached to these four plates, rests at the base on one side so that the steps are vertical and therefore parallel to the collimator slit; the longest plate is in contact with the front plate of the support, which has a rectangular window 1.8 cm wide and 3 cm high, through which the light from the collimator enters.
Two steel tie rods hold the plate of the grating firmly between the front plate of the support and another metal plate of the same thickness on which the final plate of the grating lies. ...continues