Main areas: (bio) imaging, small angle X-ray scattering, coherent diffraction. See also other sites like for example the

• X-ray optics events list at http://www.x-ray-optics.de
• lightsources.org conferences, meetings and workshops list at http://www.lightsources.org
• Image Sciences Institute, University Medical Center Utrecht, conference list at http://www.isi.uu.nl/Conferences/
• PSI Useroffice conference calendar

conferences in 2012

• ISBI 2012 (Barcelona): IEEE Symposium on Biomedical Imaging
  May 2-5, 2012
  http://www.biomedicalimaging.org/

• E-MRS spring meeting (Strasbourg)
  May 14-18, 2012
  http://www.emrs-strasbourg.com/index.php?option=com_content&task=view&id=428&Itemid=160

• SR2A 2012: Conference on Synchrotron Radiation in Art and Archaeology (New York)
  June 5-8, 2012
  https://www.bnl.gov/sr2a/

• Coherence 2012 (Fukuoka)
  18-21 June 2012
  http://rsc.riken.jp/coherence/

• Annual Meeting of the Swiss Physical Society (Zurich)
  June 21-22, 2012
  http://www.sps.ch/en/events/spg_jahrestagung_2012/

• iWoRID 2012: 14th International Workshop on Radiation Imaging Detectors (Coimbra)
  July 1-5th, 2012
  http://iworid2012.fis.uc.pt

• NSS-7: 7th International Workshop on Nano-scale Spectroscopy and Nanotechnology (Zurich)
  July 2-6, 2012
  http://www.psi.ch/nss7

• X-Ray Detectors for Synchrotron Applications (Zurich), SRI 2012 satellite workshop
  July 5-7, 2012
  http://indico.psi.ch/conferenceDisplay.py?confId=1389

• SRI 2012 (Lyon): 11th International Conference on Synchrotron Radiation Instrumentation
  July 9-13, 2012
  http://sri2012.org

• SXNS-12: International Conference on Surface X-ray and Neutron Scattering (Kolkata)
  July 25-28, 2012
  http://sxns12.com

• XRM2012, 11th International Conference on X-Ray Microscopy (Shanghai)
  August 5-10, 2012
  http://www.sinap.ac.cn/xrm2012/

• DXC: 61st Annual Denver X-ray Conference (Denver, Colorado)
  August 6-10, 2012
  http://www.dxcicdd.com

• ECM27 (Bergen) / 27th Meeting of the European Crystallographic Association
  August 7-12, 2012
  http://ecm27.ecanews.org

• Imaging Life and Matter - using photons, neutrons and muons (11th PSI Summer School on Condensed Matter Research, Zug)
  August 11-17, 2012
  http://www.psi.ch/summerschool

• XTOP2012: 11th Biennial Conference on High Resolution X-Ray Diffraction and Imaging (St. Petersburg)
  September 15-20, 2012
  http://xtop12.org/

• E-MRS Fall Meeting 2012 (Warsaw)
  September 17 - 21, 2012
  http://www.emrs-strasbourg.com/index.php?option=com_content&task=view&id=500&Itemid=172

• NOBUGS 2012: New Opportunities for Better User Group Software (Harwell Oxford)
  24th - 26th September 2012
  http://nobugs2012.org/

• ISRP-12: International Symposium on Radiation Physics (Rio de Janeiro)
  October 7-12, 2012
  http://www.cnen.gov.br/hs_isrp12/

• Frontiers in Optics 2012 / Laser Science XXVIII (Rochester)
  October 14 - 18, 2012
  http://www.frontiersinoptics.com

• MEDSI 2012 (Shanghai): 7th International Conference on Mechanical Engineering, Design of Synchrotron Radiation Equipment, and Instrumentation
  October 15-19, 2012
  http://medsi2012.csp.escience.cn

• NSS/MIC/RTSD 2012 (Anaheim, CA): IEEE Nuclear Science Symposium, Medical Imaging Conference & Workshop on Room-Temperature Semiconductor X-Ray and Gamma-Ray Detectors
  October 29 - November 3, 2012
  http://www.nss-mic.org/2012

• SAS-2012 / XV International Conference on Small-Angle Scattering (Sydney)
  18-23 November 2012
  http://www.sas2012.com

conferences in 2013

• SAOG: 29th annual meeting of the Swiss Working Group on Surface and Interface Science
  to be announced on http://www.saog-gssi.ch/

• SPIE Medical Imaging (Buena Vista, Florida)
  9 - 14 February 2013
  http://spie.org/medical-imaging.xml

• VUVX 2013: 38th conference International Conference on Vacuum Ultraviolet and X-ray Radiation Physics (Hefei)
  13-18 July, 2013
  http://vuvx2013.ustc.edu.cn/dct/page/1

• ECM28 (Warwick) / 28th Meeting of the European Crystallographic Association
  August 25-29, 2013
  http://ecm28.org

• EUROMAT 2013: European Congress and Exhibition on Advanced Materials and Processes (Sevilla)
  8. - 12. September 2013
  to be announced on http://euromat2013.fems.eu/

• ICXOM22: International Congress on X-Ray Optics and Microanalysis
  tenatively scheduled for September 2013 (see http://utagri.enea.it/eventi/meeting-internazionali/icxom-international-congress-x-ray-optics-and-micro-analysis-open-call)

• ESB2013 (Madrid): 25th European Conference on Biomaterials
  http://www.esb2013.org

• BSR2013 (Hamburg): 11th conference on Biology and Synchrotron Radiation

conferences in 2014

• XXIII IUCr2014 (Montreal): Twenty-Third Congress and General Assembly of the International Union of Crystallography
  August 5-12, 2014
  http://www.iucr2014.org/,

• IMC 2014: 18th International Microscopy Congress (Prague)
  September 7-12, 2014
  http://www.imc2014.com/

• SNI2014: Deutsche Tagung für Forschung mit Synchrotronstrahlung, Neutronen, und Ionenstrahlen an Großgeräten

• SXNS-13: International Conference on Surface X-ray and Neutron Scattering

• SSOM 3D-microscopy symposium

• SR2A 2014: Conference on Synchrotron Radiation in Art and Archaeology

• NOBUGS 2014: New Opportunities for Better User Group Software
  to be linked from http://www.nobugsconference.org/Conferences

conferences in 2015

• SAS-2015 / XVI International Conference on Small-Angle Scattering (Berlin)

• EUROMAT 2015: European Congress and Exhibition on Advanced Materials and Processes