Experiences and expectations of a novel X-ray microsource with focusing mirror. I. erratum.

The following are corrections to a paper by Bloomer & Arndt [(1999), Acta Cryst. D55, 1672-1680]. The entry in the second row of the I(MAR) column of Table 1(b) on page 1674 should read 6.

Experiences and expectations of a novel X-ray microsource with focusing mirror. I.

Data are presented from a novel microfocus X-ray generator installed with a choice of ellipsoidal specularly reflecting mirrors. Diffraction data from proteins show the useful flux from this low-power device to be approaching equivalence with that from many far more powerful generators. Intensity measurements show that for small crystals the brilliance is now restricted by the performance of the mirror, which appears to be limited by imperfections in the figure of its surface rather than by a low reflectivity.

A neutron television camera detector.

The system under development has a large counting rate capability; this is extremely important where the total background count exceeds the total counts in the signals of interest. Its spatial resolution is of the order of one mm, which is perfectly adequate for neutron work, while the screen size of 400 mm is reasonable. The main limitation of the system is its limited counting efficiency, and this is directly attributable to the optical self-absorption of the neutron phosphor.