Vol.11 - Spring Issue 2011
Marresearch integrates the New GeniX 3D in its marµX
Marresearch recently accessed the performances of the GeniX 3D Cu High Flux, our new beam delivery system for single crystal diffraction applications.
Marresearch is offering a complete x-ray data collection system for macromolecular and small molecule x-ray crystallography under the trademark “marµX”, integrating the new GeniX 3D Cu High Flux x-ray source together with the mar345 image plate detector and the mardtb goniostat. According to Dr Claudio Klein ‘‘Marresearch needs a reliable supplier of a powerful x-ray source in order to offer a complete x-ray setup that fulfills today’s requirements for most x-ray applications’’. This has been achieved successfully for several years now with the integration of the GeniX version in the “marµX”. The new GeniX 3D Cu HF was carefully tested by Marresearch in comparison to the previous model. It proves to deliver more useful photons at the sample in the order of magnitude of 1.5. ‘‘This makes the choice of a small scale generator setup even more attractive’’ says Dr Claudio Klein. This Application Note from Marresearch describes data collections on different small molecule crystals comparing GeniX 3D to previous GeniX model.
Comparison of the GeniX 3D Cu HF beam delivery system with the GeniX Cu VHF system
Courtesy of Dr Claudio Klein, Marresearch Gmbh, Norderstedt
The marµX system (Fig.1) is a very compact yet powerful complete X-ray setup suitable for both protein and small molecule data collection as well as other types of experiments. The marµX system consists of a mar345 image plate detector, a mardtb goniometer system and the new 2010 micro-focus generator from XENOCS - the GeniX 3D Cu HF - operated at 30 W (50 kV / 0.6 mA).
In this study we compare the new GeniX 3D Cu HF system with the previous GeniX Cu VHF generator operated at 50 W (50 kV / 1.0 mA). The new system features an entirely new tube setup including a newly designed and highly optimized x-ray optic. Thanks to a number of major improvements the new generator delivers more X-ray photons onto the sample despite of running at lower power (30 W instead of 50W).
In order to assess the quality of the new system, several small molecules of different types and sizes have been collected. Here we present a selection of typical results.
| The New GeniX | Previous GeniX | |
|---|---|---|
Beam at crystal positionThe pictures show an area of 0.5 x 0.5. The color coding reflects the measured intensity of the beam. |
 |
 |
Distance source - optic center |
8 cm | 14 cm |
Distance optic center - focus |
30 cm | 39 cm |
Spot size in focus (FWHM) |
175 µm x 175 µm | 190 µm x 190 µm |
Flux within 100 µm at focus |
9 x 107 photons/sec | 5 x 107 photons/sec |
Divergence (mrad @ FWHM) |
~ 6 x 6 | 5.4 x 5.4 |
Total flux |
> 400 Mph/s | > 300 Mph/s |
Data collection and processing
The data for all crystals were collected on the same mar345dtb detector system. When exchanging the generators, the beam was carefully realigned. The crystals needed to be taken off the goniometer but they were remounted in a position very close to where they have been mounted before. Data were collected at:
- 90 mm distance crystal-to-detector giving 1.5 Ang. resolution at the edge
- 5 deg./image
- 72 images (i.e. 360 deg. of data)
- constant exposure time (typically 40s/image)
Data were processed using the Automar program suite.
| Anil | Bitartrate1 | Bitartrate2 | |
|---|---|---|---|
Crystal |
 |
 |
 |
Space group |
P 1 | P 212121 | P 212121 |
Unit cell axes a, b, c [Ang.] |
a=9.7 b=13.5 c=16.7 | a=7.6 b=7.8 c=11.1 | a=7.6 b=7.8 c=11.1 |
Mosaicity [deg.] |
0.6° | 0.6° | 0.3° |
Size of crystal W x H x L [µm] |
350 x 180 x 500 | 120 x 120 x 2000 | 30 x 60 x 500 |
Optics |
NEW - Old | NEW - Old | NEW - Old |
# reflections |
4166 - 4194 | 1287 - 1316 | 1417 - 1387 |
Multiplicity |
3.5 - 3.6 | 9.8 - 9.9 | 10.5 - 10.3 |
Rsym |
4.4 - 4.5 | 3.6 - 3.7 | 3.1 - 3.6 |
Intensity |
12276 - 8717 | 100706 - 57667 | 29244 - 23734 |
Scale I NEW : I Old |
1.41 | 1.75 | 1.23 |
Conclusion
The net intensities of reflections in the final data set depend on several factors:
- the amount of x-rays photons delivered by the generator in a small area
- divergence of x-ray beam
- size of crystal
- mosaicity of crystal
It is very difficult if not impossible to crystallographically separate the contributions of those individual factors. Still, by comparing the diffracted net intensities of a number of crystals of different sizes and forms, meaningful conclusions can be drawn about the performance of the x-ray equipment. In this study, we conclude that within limits of accuracy, the new GeniX 3D Cu HF source is stronger than the previous model despite of running at lower power. The gain in performance for crystallographic purposes is in the same order of magnitude as the specified x-ray photon flux, up to 1.8.
