Obituaries

Lachlan Cranswick (1968-2010)

The untimely passing of Lachlan Cranswick leaves a large vacuum within the powder diffraction community that will be very hard to fill.  It is not an exaggeration to say that he was a dynamo, and was one of those rare people who readily volunteered to take on mundane tasks without persuation.  He looked after the Computer Corner in the CPD newsletters for 11 years and edited a special software newsletter (number 20) in 1998.  On the technical side Lachlan was involved in a number of the CPD projects including Quantitive Phase Analysis RR and Rietveld Refinement RR as well as all three of the SDPD round robins (http://sdpd.univ-lemans.fr/SDPDRR/index.html, http://sdpd.univ-lemans.fr/sdpdrr2/index.html, and http://sdpd.univ-lemans.fr/SDPDRR3/index.html). 

People will forever associate Lachlan with the CCP14 website that became the global software resource for powder diffraction. For the wider crystallographic community he was the most recent chair of the IUCr Computing Commission (needless to say their website is now one of the more sophisticated of all the commissions), ran the software fairs at the IUCr Congresses and co-organized the popular "Under the Bonnet" workshop at the Geneva EPDIC meeting. Since arriving in Canada in 2003 he became a member of the Canadian National Committee for Crystallography and the local committee for the 2014 IUCr Congress in Montreal. He also ran the websites for the Canadian Institute for Neutron Scattering, the Toronto ACA meeting, and others too numerous to mention. 

Earlier this year a new mineral was approved with the name "cranswickite".  Appropriately the structure was solved using powder diffraction data by Ron Peterson at Queens University in Kingston, Ontario, Canada. As a measure of the regard with which he was held in Canada, at the time I was working with mineralogists at the University of British Columbia in Vancouver on the structure of another new mineral we intended to name cranswickite.  We were scooped to the IMA submission by a few weeks, but this is one instance where it really didn't matter. It must be one of the few times in mineralogy where there was competition for a mineral name, even if we didn't know it at the time. I also had the rather sad job of filling in for Lachlan (or at least trying) at the Canadian Powder Diffraction Workshop in late June.

It goes without saying that he will be sorely missed both within Canada and elsewhere.

Pamela Whitfield, CPD Chair, Ottawa, Canada (September 2010)

The open access obituary by Nikki Scarlett, Ian Swainson and Jeremy Cockcroft that was published in the Journal of Applied Crystallography can be found at http://journals.iucr.org/j/issues/2010/05/01/es0383/index.html

Joerg Bergmann (1956-2010)

Joerg Bergmann passed away after a long desired transplant operation, just after visiting the EPDIC 12 in Darmstadt.  Joerg was an enthusiastic X-ray powder diffractionist and he especially enjoyed very much the honoring of Hugo Rietveld at this conference.  The day before his tragic operation Joerg delivered the last update of his software BGMN for testing of the new features and updated his webpage http://www.bgmn.de/.  His last developments were new tools for the simultaneous refinement of data from different sources such as X-ray and neutron and for the recursive calculation of XRD patterns from disordered layered structures.

Joerg Bergmann studied physics in Dresden and in 1984 he presented his Ph.D thesis with the translated title Contributions to evaluation and experimental design on X-ray powder diffraction (http://www.bgmn.de/download/thesis.pdf).

Joerg was an exceptionally gifted mathematician.  He developed a solution for convolution-based peak profile modeling, which was integrated in a peak search program and combined with options for optimized measuring strategies.  Unfortunately, these results could not be published before the German reunification, at the EPDIC 1 in Munich (Querner et al., 1991).

Motivated by colleagues and friends, Joerg started development of a Rietveld program based on his "fundamental parameter" peak shape model in the early 90s.  I was as an inexperienced user of DBWS and was shocked when I first tested Joerg's software in 1993.  Some mysterious things happened, and the expected results were all written in the results file.  I suspected there were some dirty tricks or that some hidden parameters were fixed, but the great convergence behavior could be consistently reproduced.  This high level performance remains as one of the fascinating characteristics of BGMN to date.

Despite his poor health, Joerg worked tirelessly on the BGMN program as a private project and hobby without significant institutional support.  There are numerous impressive results and publications obtained with Joerg's software that have been noticed by the community including the IUCr indexing round robin (http://sdpd.univ-lemans.fr/sdpdrr2/sdpdrr2-CPD.pdf) and the CMS Reynolds Cup in quantitative mineral analysis (http://www.clays.org/SOCIETY%20AWARDS/RCresults.html).

Joerg's BGMN website (http://www.bgmn.de/methods.html#cite) also contributed to his reputation in the community of crystallographers and X-ray powder diffractionists and unselfishly provided valuable and practical information to people working in the field.

Joerg was known as a great personality, open in discussions and helpful in solving any scientific problems.  Sometimes it was hard to follow his highly technical thoughts, but he patiently answered any questions.  He was impressively fast at fixing bugs and implementing new features of his software that were related to someones individual scientific problem.  

Outside the scientific world he loved singing in the University chorus, hiking, and cooking exclusive meals. Joerg was also a passionate photographer and artist.  Some of his photos and computer graphics can be seen here http://www.jbergmann.de/.  Joerg's awareness about his unstable health allowed him to live intensely with the time he had and share the beauty and passion in his life with his beloved wife Anne.

Joerg Bergmann will be sorely missed by friends and colleagues in Germany and around the world.

Reinhard Kleeberg, Freiberg, Germany (October 2010)

Reference:

Querner, G., Bergmann, J. & Blau, W. (1991) "A method for data reduction and optimal experimental design in XPD". Materials Science Forum 79-82 (1) p107-112.