Changes history

This LOG page was started on January 1, 2001 to keep the server users updated with the latest changes.

• The output of X0h_form and X0p_form was re-worked to provide better formatting, especially on mobile devices, and better compliance with the HTML standard.
   
  

• Two service programs, wwwwatch and wwwunzip were converted to Perl in order to extend functionality and simplify troubleshooting. ATTENTION: if you are using Perl automation scripts with GID_sl, TER_sl, TRDS_sl, or MAG_sl programs, please download a new version from the Automation web page or replace in your existing scripts wwwwatch.exe and wwwunzip.exe with wwwwatch.pl and wwwunzip.pl respectively.
   
  
• Example Python automation scripts have been posted at the Automation web page. The scripts were converted from their Perl counterparts using ChatGPT and then manually refined and tested.
   
  

• A new crystal structure of Li1Mn2O4 (see doi.org/10.1016/j.jallcom.2022.164027) has been added to the X0h DB. Thanks to Dr. Azat Khadiev from DESY (Hamburg, Germany).
   
  
• A caching problem at Cloudflair has been discovered: Cloudflair caches CGI requests to X-ray server. If new request has an URL identical to a cached one, Cloudflair does not send it to X-ray Server, but returns a cached response. This broke the task progress watching functionality perhaps quite long ago. A workaround to overcome the has been applied to the web browser interface, but if you use the automation scripts downloaded from X-ray Server, you will will need to update them. Modified scripts should be ready for downloading in a few days. Please watch this web page for the update readiness notice.
   
  

• A new crystal structure of PtSe2 has been added to the X0h DB. Thanks to Dr. Zdenko Zaprazny from the Institute of Electrical Engineering, Slovak Academy of Sciences. It should be noted that data on the PtSe2 lattice constants very significantly between various sources. The constants in the X0h DB correspond to PDF-2 record number 00-18-0970 from International Centre for Diffraction Data (ICDD).
   
  

• A new crystal structure of Sr2IrO4 has been added to the X0h DB. Thanks to Dr. Longlong Wu from the Brookhaven National Lab.
   
  

• A new crystal structure of Sr3Al2O6 has been added to the X0h DB. Thanks to Dr. Yorick Birkholzer from the University of Twente, Netherlands.
  Also, the size of the X0H buffers were increased from 10 atomic components per structure and 32 coordinates in the unit cell per atom to 20 and 200 respectively.
   
  

• A new crystal structure of Tungsten Disulfide (WS2) has been added to the X0h DB. Thanks to Dr. Zdenko Zaprazny from the Institute of Electrical Engineering Slovak Academy of Sciences.
   
  

• A new crystal structure of BiFeO3 (Bismuth Ferrite) has been added to the X0h DB. Thanks to Saptam Ganguly from the Catalan Institute of Nanoscience and Nanotechnology, ICN2 (Catalonia, Spain).
   
  

• Fixed a bug in the new algorithm for interpolating dispersion corrections which had been introduced 2023/12/02. In some rare cases the bug could lead to huge random and no-sense X0h values, like ~10 ¹⁵ instead of normally ~10 ^-5. Please rerun the calculations if you observed some nonsense values in the past 10 days.
   
  

• The algorithm for interpolating the dispersion corrections in the X0h system has been tweaked for a better stability near absorption edges. It resolved the error observed in the g1923150 calculation and could possibly help in rare similar cases. Also the X0h was improved.
   
  

• A new crystal structure of CoPS3_250K (see doi.org/10.1088/1361-648X/aa8a43) has been added to the X0h DB. Thanks to Dr. Azat Khadiev from DESY (Hamburg, Germany).
   
  

• A new crystal structure of CeO2 has been added to the X0h DB. Thanks to Dr. Ivan Vartaniants from DESY (Hamburg, Germany).
   
  

• A new crystal structure of Fe3O4 has been added to the X0h DB. Thanks to Yifan Xu, Forschungszentrum Juelich (Germany).
   
  

• Two new crystal structures, Li0.5Fe2.5O4_stchmtrc (Li(0.5)Fe(2.5)O4_stochiometric) and Li0.5Fe2.5O4_solutn (Li(0.5)Fe(2.5)O4_solution) have been added to the X0h DB. Thanks to Dr. Arturas Vailionis from the Stanford University. In the Li0.5Fe2.5O4_stchmtrc only half of Li sites (as compared to LiF2O4) contain Li atoms and the rest are taken by Fe. This structure can also be viewed or named as LiFe5O8. The Li0.5Fe2.5O4_solutn structure is a solid solution where Fe randomly occupies all possible Li sites with the probability of 75% and the Li atoms can be found in these sites with the probability of only 25%.
   
  

• A new crystal structure of FePS3 has been added to the X0h DB. Thanks to Dr. Azat Khadiev from DESY (Hamburg, Germany).
   
  

• A new crystal structure of Magnetite (Fe²⁺Fe³⁺₂O₄) has been added to the X0h DB. Thanks to Dr. Francesco Borgatti from Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), Bologna, Italy.
   
  

• A new crystal structure of LaNiO2 has been added to the X0h DB. Thanks to Wenjie Sun from Nanjing University, China.
   
  

• Four new crystal structures:
  FeTiO3,
  Ca2RuO4_HiTemp (above metal-insulator transition, 400 K),
  Ca2RuO4_LoTemp (below metal-insulator transition, 180 K),
  Ba2ScRuO6
  have been added to the X0h DB. Thanks to Dr. Yorick Birkhoelzer from the Cornell University.
   
  

• New Ga2O3-kappa crystal structure has been added to the X0h DB. Thanks to Dr. Claudio Ferrari from the Italian National Research Council (CNR).
   
  

• Two new crystal structures, LaInO3 and BaSnO3 have been added to the X0h DB. Thanks to Dr. Vladimir Kaganer from the Paul Drude Institute, Berlin, Germany.
   
  

• New FeGe2-alpha crystal structure has been added to the X0h DB. Thanks to Moritz Hansemann and Dr. Michael Hanke from the Paul Drude Institute, Berlin, Germany.
   
  

• New Ga2O3-alpha crystal structure has been added to the X0h DB. Thanks to Dr. Yorick Birkhoelzer from the Cornell University.
   
  

• New Langasite crystal structure has been added to the X0h DB. Thanks to Dr. Anton Kulikov from the Institute of Crystallography, Moscow, Russia.
   
  

• All automation scripts were updated to handle the Cloudflare proxy. Apparently moving the server behind Cloudflare on May 31, 2022 broke all the client scripts for automated access to the server. If you downloaded any automation scripts before August-2022, please re-download them. Please note that Dr. Luca Rebuffi has also updated his OASYS XRayServer plugin. If you are using this plugin, please execute the plugins update process in OASYS. Thanks to Dr. Martin Seyrich from DESY (Hamburg, Germany) for reporting the problem.
   
  

• New crystal structure InGaAs has been added to the X0h DB. Indium gallium arsenide (InGaAs) (alternatively gallium indium arsenide, GaInAs) is a ternary alloy (chemical compound) of indium arsenide (InAs) and gallium arsenide (GaAs). As so, the content of In and Ga may vary and the right notation of the structure is Ga_xIn_1-xAs. The structure added to the DB corresponds to x=0.47, i.e. Ga_0.47In_0.53As or In_0.53Ga_0.47As. According to Wikipedia, this is the most common and the most important Ga_xIn_1-xAs alloy composition from technological and commercial standpoints.
   
  

• By the Lab mandate X-Server was placed behind the Cloudlare proxy.
   
  

• New crystal structure Pentaerythritol (PET) has been added to the X0h DB. Thanks to Dr. Heath Lefevre from the University of Michigan.
   
  

• The server was migrated from the Redhat/CentOS Linux to Ubuntu/Mint Linux.
   
  

• New crystal structure VO2_Rutile has been added to the X0h DB. Thanks to Yorick Birkholzer from the University of Twente, Netherlands.
   
  

• New crystal structure SmNiO3 has been added to the X0h DB. Thanks to Yorick Birkholzer from the University of Twente, Netherlands.
   
  

• New crystal structure C8H5KO4 has been added to the X0h DB. Thanks to Eduard Ibragimov from the Moscow State University, Russia.
   
  

• New crystal structure FeBO3 has been added to the X0h DB. Thanks to Dr. Anton Kulikov from the Institute of Crystallography, Moscow, Russia.
   
  

• New crystal structure Hfo2 has been added to the X0h DB. Thanks to Dr. Kit de Hond from the University of Twente, Netherlands.
   
  

• A javascript bug in the crystal structure submission HTML form has been fixed. The bug was causing incorrect disabling of lattice angles input for some Trigonal structures. Thanks to Dr. Kit de Hond from the University of Twente, Netherlands for reporting the issue.
   
  

• Two new external databases have been added to the X0h system interpolating dispersion corrections df' and df" for all X-ray Server programs. These are the David Wind data and the Chantler/NIST data. Data are available in the range 10 eV to 100 KeV for Windt and 10 eV to 450 KeV for Chantler. These data complement previously added Henke-Gullikson-Davis/LBL data and the Brennan-Cowan/SSRL data. See more details on the X0h webpage.
   
  

• New crystal structure Black_Phosphorus has been added to the X0h DB. Thanks to Eric Nilsson from the Lund University, Sweden.
   
  

• The BRL program (multiple Bragg diffraction) has been switched to a new calculation engine based on LAPACK.
   
  
• A bug in BRL leading to a reduced accuracy has been fixed.
   
  

• Programs TER_SL, TRDS_SL, MAG_SL, and the stable release of GID_SL have been switched to new calculation engine based on LAPACK and CPOLY.
   
  
• Several bugs in BRL and X0H have been fixed. It eliminated rare crashes due to non-initialized variables.
   
  
• Task monitoring system has been switched from C to Perl, which helped selecting right program for the submitted task.
   
  

• New beta-version of the GID_SL was released. It is available along with the old stable version. The release bring the following enhancements:
  1. Up to 10x faster calculations due to the reduction of the scattering matrix size.
  2. Option to specify phases for the Xh (Chi-h) parameters of the layers.
  3. Option to calculate X-ray Standing Waves (XSW) in crystals.
  4. New calculation engine based on LAPACK and CPOLY.
  
   
  

• The way the substrate da/a parameter is interpreted in the GID_SL program was changed. In the past all surface layers with unspecified da/a were assigned to have lattice spacing of unstraned substrate. It meant that when one specified non-zero substrate da/a, these layers were interpreted as strained with respect to the substrate. Also, automatic da/a calculations in the layers (da/a=auto) were disabled when non-zero substrate da/a was specified. Now, after the change, all surface layers with unspecified da/a are assigned lattice spacing of the strained substrate and with da/a=auto the strains calculations are allowed and the automatic strains are also calculated with respect to strained substrate lattice. Overall, with the new scheme, entering non-zero substrate da/a simply shifts the Bragg curve over angles without shape change.
   
  
• Lattice constant "c" of GaN was changed from c=5.178 Å to c=5.186 Å in order to bring it in accordance with the Wikipedia data . The "a" parameter remained unchanged at a=3.186 Å as it had been in the agreement. It must be noted that there is a considerable spread in the GaN lattice constants between different sources. For example, this source reports that the "a" data may be found in range 3.160 - 3.190 Å and "c" in the range 5.125 - 5.1900 Å. Still,c=5.186 Å seems to be closer to more sources than c=5.178 Å.
   
  

• X-ray Server passed the milestone of 5,000,000 calculations.
   
  

• Two new crystal structures of GdSb and LuPtBi have been added to the crystals database. Thanks to Hadass Inbar from the University of California, Santa Barbara (UCSB).
   
  

• Two new crystal structures of Si_primitive and SiFe_primitive which may appear in epitaxial films have been added to the crystals database. These structures are similar to Ge_primitive and GeFe_primitive added 2017/08/09. Thanks to Bernd Jenichen from the Paul Drude Institute, Berlin, Germany.
   
  

• New crystal structure gamma-Ga2O3 has been added to the X0h DB. Thanks to Mr. Tobias Hadamek from the University of Texas at Austin.
   
  

• New crystal structure Fe2Mo3O8 has been added to the X0h DB. Thanks to Dr. Mark Dean from Brookhaven National Lab.
   
  

• New crystal structure LaNiO3_cubic has been added to the X0h DB. Thanks to Dr. Arturas Vailionis from Stanford University. Note that this structure complements previously available LaNiO3 which is orthorhombic.
   
  

• Plain http access to the server was removed due to new Argonne security policies. Please use the secure https protocol instead. Also please note that if you have any scripts for automated access to X-Server or web browser bookmarks, they need to be tweaked for using https instead of http, i.e. please replace http://x-server.gmca.aps.anl.gov by https://x-server.gmca.aps.anl.gov.
   
  

• New crystal structure LaFeO3_cubic has been added to the X0h DB. Thanks to Dr. Arturas Vailionis from Stanford University. Note that this structure complements previously available LaFeO3 which is orthorhombic.
   
  

• Secure access to the Server using the https protocol has been implemented. The old http protocol is planned to be ceased down shortly. Please note that if you have any scripts for automated access to X-Server or web browser bookmarks, they need to be tweaked for using https instead of http, i.e. please replace http://x-server.gmca.aps.anl.gov by https://x-server.gmca.aps.anl.gov.
   
  

• New crystal structure Cu2ZnSnSe4 has been added to the X0h DB. Thanks to Dr. Hitoshi Tampo from the National Institute of Advanced Science and Technology, Japan.
   
  

• A new tool to print full dumps of the X0h atom scattering properties records was added. The tool is accessible either via a web form or via a downloadable Perl script.
   
  

• X-Server was moved to a different server and from Ubuntu-16.04 to CentOS-7.4. While before the move X-Server had been hosted on my desktop computer, now it runs as an Apache VirtualHost on the GMCA@APS dedicated webserver.
   
  

• New crystal of Molybdenite (MoS2) has been added to the X0h DB. Thanks to Dr. Alexander Gerlach from the University of Tuebingen, Germany.
   
  

• New crystal of SnO2 (Cassiterite) has been added to the X0h DB. Thanks to Dr. Hugo Mangar from the University of Targu, Estonia.
   
  

• New crystal of NdScO3 has been added to the X0h DB. Thanks to Dr. Kit de Hond from the University of Twente, Netherland.
   
  

• New crystal of La2CuO4_tetragonal has been added to the X0h DB. Thanks to Arturas Vailionis from Stanford University.
   
  
• Please note that after moving X-Ray Server from Windows to Linux, the names of the programs became case-sensitive (all lower case). So, if you have any scripts accessing the Server, please verify that they call e.g. gid_form.pl and wwwunzip.pl instead of GID_form.pl or WWWunzip.pl.
   
  

• Lattice constants of Quartz crystal were updated to a more modern Wikipedia data (see this page). Thanks to Dr. Nino Pereira from Ecopulse, Inc. for providing data links.
   
  
• New crystal of LaCuO3 has been added to the X0h DB. Thanks to Arturas Vailionis from Stanford University.
   
  

• Lattice constant of Diamond crystal was changed from 3.559 to a more modern data of 3.5668 (see this source). Thanks to Hendrik Bernhardt from the University of Jena, Germany.
   
  
• New crystal of LaCuO3 has been added to the X0h DB. Thanks to Arturas Vailionis from Stanford University.
   
  

• A bug in the X0h system supplying X-ray scattering factors to all X-Server programs was fixed. The bug introduced at the beginning of September-2017 when the Server was ported from Windows to Linux was leading to ~10-20% incorrect values of the absorption part of X0 and Xh. Thanks to Maksim Rakitin from NSLS-II for noticing and reporting the bug.
   
  

• New PbZrO3 crystal structure has been added to the crystals database. Thanks to Dr. Kit de Hond from the University of Twente, Netherland. Plasma Physics Laboratory.
   
  

• New PbTiO3 crystal structure has been added to the crystals database. Thanks to Dr. Kit de Hond from the University of Twente, Netherland. Plasma Physics Laboratory.
   
  

• The server was moved from Windows OS to Linux. Please watch for not working pages due to extensive changes. The main issue may be related by case sensitifity of Linux file system. If something does not work, first try to reload the web page (shift+reload) in your web browser. If that does not help, please contact me.
   
  

• New KAP (KC₆H₄COOH.COO) crystal structure has been added to the crystals database. Thanks to Brian Kraus from the Princeton Plasma Physics Laboratory.
   
  

• Two new crystal structures of Ge_primitive and GeFe_primitive which may appear in epitaxial films have been added to the crystals database. Thanks to Bernd Jenichen from the Paul Drude Institute, Berlin, Germany.
   
  

• A new Cr2AlC crystal structure has been added to the crystals database. Thanks to Mr. Cosmin C. Popescu from Drexel University.
   
  

• Three new crystal structures: GdScO3, LaFeO3 and NdGaO3 have been added to the crystals database. Thanks to Kristoffer Kjaernes from the Norwegian University of Science and Technology.
   
  

• An javascript filter for allowed characters has been added to the GID_SL, TER_SL, MAG_SL and TRDS_SL input forms. The filter should prevent inputting non-ASCII and UTF symbols into the surface profile field. It is aimed at preventing submissions which would cause the respective X-Server program to return an error message about incorrect input syntax. The X-Server programs accept ASCII letters, digits, and the following symbols: !#%&()*+,-./:;=?@[]^{}~. Non-English letters, UTF symbols, and "$'<>|\ are not allowed.
   
  

• A new RuO2 crystal structure has been added to the crystals database. Thanks to Dr.Yang Wang from Oak Ridge National Lab.
   
  

• The obsolete interface programs gid_form.exe, mag_form.exe, ter_form.exe, trds_frm.exe, and welcome.exe were finally removed from the server. They had been replaced by ".pl" versions on 2013/06/26 (see respective note in this log) and kept for almost 3 years solely for compatibility with those who may have old bookmarks or automation scripts, but everything has its lifetime limits and maintenance effort. Please upgrade to more modern ".pl" versions if you have to.
   
  

• The X0h DB Structure Verification Tool was extended to input new structures not only in the wizard style, but also directly in the X0h DB format.
   
  

• X-Server moved from a 9-years old computer to a new faster hardware and upgraded to Windows-10.
   
  

• A new tool to print full dumps of the X0h DB records was added. The tool is accessible either via a web form or via two downloadable Perl scripts for individual structures and for the whole DB respectively.
   
  
• A new X0h DB Structure Verification Tool was added. Also, the structures submission web page was redesigned.
   
  
• A bug in TER_sl was fixed. Under certain conditions the bug could case calculation of physically meaningless very small values for the Critical Angle of X-ray Total External Reflection and then TER_sl would fail.
   
  

• A new Sn2P2Se6 crystal structure has been added to the crystals database. Thanks to Martin Kubli from Swiss Federal Institute of Technology (ETH Zurich).
   
  

• A minor bug was fixed in the LiNbO3 structure: one of 18 oxygen coordinates was incorrect. Thanks to Dr. Francois-Xavier Darras from CEA/LETI, Francy for providing the correction.
   
  

• A bug was fixed in the Standing Waves calculations by TER_sl. The bug could cause incorrect jumpy Standing Waves profiles at large distances above the surface. Thanks to Georgi Gochev from Max Planck Institute of Colloids and Interfaces, Germany for reporting the problem.
   
  

• A new NaOsO3 crystal structure has been added to the crystals database. Thanks to Valerio Scagnoli from Swisss Light Source.
   
  

• Fixed a minor, but annoying bug in Brl causing the program to crash at Step-1 while searching for multiple diffraction cases. The bud only appearing when the diffraction vector was perpendicular to the surface normal or almost perperdicular within +-2degr.
   
  

• A new service page X0h DB Listing has been added. The page allows to display the lists of structures contained in the X0h databases. User can requests either the lists of available structure names or the dumps of structure descriptions. A corresponding script is made available too via the Automation page.
   
  

• A security filter has been added to parsing of web input. Now some special symbols like '"*?$!@% are no longer allowed. This should not affect user input, but may restrict what can be included into optional comments. For example, one cannot include an email address since it contains "@". Then, the comments cannot be made in languages containing non-ASCII letter. Finally, now the comments themselves can start with ";" only since "!" is no longer allowed. I apologize for these inconveniences: we have to "thank" hard working hackers for the need of all these security measures.
   
  
• A new structure, LaNiO3 has been added to the crystals database. Thanks to Alexandra Senegas from University Paris-Sud, France.
   
  

• A new structure, ADP (Ammonium Dihydrogen Phosphate, NH4H2PO4) has been added to the crystals database. Thanks to Dr. Elisa Buffagni from IMEM-CNR, Parma, Italy.
   
  

• A new structure, Gd2O3 has been added to the crystals database. Thanks to Vladimir Kaganer from the Paul Drude Institute, Berlin, Germany.
   
  

• Three new structures: Lu2O3cub, La2O3cub, and La2O3hex have been added to the crystals database and the Pr2O3 structure was corrected. Thanks to Vladimir Kaganer from the Paul Drude Institute, Berlin, Germany.
   
  

• Two new structures: DyScO3 and SrTiO3_tetragonal have been added to the crystals database. Thanks to Jasper Robbert Anton Smit from Stanford University.
   
  

• The BRL program was extended to offer a choice of two multiple diffraction configurations (see O and O' on the BRL web page Figure 1) when in both cases the incident wave can enter the cryatal. Thanks to John Sutter from Diamond Light Source.
   
  

• The server switched to Apache-2.4 under Windows7 and the server program recompiled with Mingw GNU Fortran and CodeBlocks. The server is now fully portable and can run under both Windows and Linux in either root web server directory or a subdirectory. The current choice of Windows-7 platform is due to sharing the server computer for other needs like office activities.
   
  

• New versions of the Server programs have been installed that are modified to compile with GNU Fortran and also to support relative Server path. This is the first step of porting the Server from phasing out Compaq Visual Fortran and Windows XP platfrom to GNU Fortran and Linux. After a week of the new code testing with the old compiler, the programs will first be replaced by those compiled with GNU Fortran and then after another week of testing will be moved to Linux. Please be alert of potential burst of bugs during this transitional period. Any bugs reports will be highly appreciated.
   
  
• Most of automation scripts were updated because in preparation to moving the Server to case-sensitive Linux OS, the files were converted to lower case. If you had used the automation scripts before, you may need to download new versions.
   
  

• A crystal structure of Co2TiSi was added to the crystals database. Thanks to Bernd Jenichen from the Paul Drude Institute, Berlin, Germany.
   
  
• A crystal structure of SrVO3 was added to the crystals database. Thanks to Arnaud Fouchet from the University of Versailles Saint-Quentin-en-Yvelines, France.
   
  

• Fixed a minor bug in TRDS_SL: when the program was encountering certain rare type of errors, it was not reporting them to the web server and for a user it looked as the program kept calculating indefinitely.
   
  

• All GET-style requests were switched from EXE to PERL wrappers to provide uniform handling with the POST-style requests. The GET-style web templates and example automation scripts were modified accordingly. Users possessing earlier dowloaded or modified automation scripts should make a tiny change: replace <prg>_form.exe by <prg>_form.pl (for example, gid_form.exe by gid_form.pl).
   
  
• A warning was added to processing the GET-style web requests when the received query string gets close to 2024 bytes. Users will receive this warning on the web page shpowing results for their GID_SL, TER_SL, MAG_SL and TRDS_SL requests.
   
  

• A bug was fixed in the javascript disabling/enabling fields on the web form for GID_SL, TER_SL, MAG_SL and TRDS_SL. The bug was causing incorrect disabling of some form fields when clicking "Back" in Internet Explorer.
   
  
• A bug was fixed in the scripts parsing the POST web input for GID_SL, TER_SL, MAG_SL and TRDS_SL. The bug was that when a field on the web form was disabled, the form parsing scripts skipped it instead of assigning a default value. It could cause some parameters to shift their positions in the inputs array, thus leading to their incorrect interpretation. The most typical occurrence of the bug was when user was entering scan limits in arc seconds, but the input was interpreted in degrees because another angular units parameter was disabled and skipped in the input stack. The bug did not affect the older GET web input.
   
  

• Aluminium (Aluminum) crystal structure was added to the crystals database. Thanks to Bernd Jenichen from the Paul Drude Institute, Berlin, Germany.
   
  

• Added a CGI POST method to call the TRDS_sl program. This method complements the previously used and still available CGI GET method where all parameters are transferred as a part of the URL string. The issue had been that the GET method may have problems with some firewalls and the Internet Explorer when the URL request string exceeds 2 kilobytes (certain firewals may truncate the URL request string to even shorter length of 1K). That had been the case with GID_SL, TER_SL, MAG_SL and TRDS_SL when users had long surface profiles consisting of several dozens of layers. In the POST method, data is no longer a part of the URL string and this restriction is removed, although TRDS_SL itself still has a restriction of 5000 layers in the profile.
   
  
• The templates for a scripted access to TRDS_SL using the POST method added too.
   
  
• Rewrote TRDS_SL scripted access templates (the example client-side Perl scripts) to use the associated array representation of the WWW forms, which made them more compact and hopefully easier to understand.
   
  
• The implementations for TER_SL, GID_SL and MAG_SL had been rolled out earlier.
   
  

• Added a CGI POST method to call the MAG_sl program. This method complements the previously used and still available CGI GET method where all parameters are transferred as a part of the URL string. The issue had been that the GET method may have problems with some firewalls and the Internet Explorer when the URL request string exceeds 2 kilobytes (certain firewals may truncate the URL request string to even shorter length of 1K). That had been the case with GID_SL, TER_SL,MAG_SL and TRDS_SL when users had long surface profiles consisting of several dozens of layers. In the POST method, data is no longer a part of the URL string and this restriction is removed, although MAG_SL itself still has a restriction of 5000 layers in the profile.
   
  
• The templates for a scripted access to MAG_SL using the POST method added too.
   
  
• Rewrote MAG_SL scripted access templates (the example client-side Perl scripts) to use the associated array representation of the WWW forms, which made them more compact and hopefully easier to understand.
   
  
• The implementations for TER_SL and GID_SL had been rolled out earlier.
   
  

• Added a CGI POST method to call the TER_sl program. This method complements the previously used and still available CGI GET method where all parameters are transferred as a part of the URL string. The issue had been that the GET method may have problems with some firewalls and Internet Explorer when the URL request string exceeds 2 kilobytes (certain firewals may truncate the URL request string to even shorter length of 1K). That had been the case with GID_SL, TER_SL, MAG_SL and TRDS_SL when users had long surface profiles consisting of several dozens of layers. In the POST method, data is no longer a part of the URL string and this restriction is removed, although TER_SL itself still has a restriction of 5000 layers in the profile.
   
  
• The templates for a scripted access to TER_SL using the POST method added too.
   
  
• Rewrote GID_SL and TER_SL scripted access templates to use associated array representation of WWW forms, which made them more compact and hopefully easier to understand.
   
  

• Added a CGI POST method to call the GID_sl program. This method complements the previously used and still available CGI GET method where all parameters are transferred as a part of the URL string. The issue had been that the GET method may have problems with some firewalls and Internet Explorer when the URL request string exceeds 2 kilobytes (certain firewals may truncate the URL request string to even shorter length of 1K). That had been the case with GID_SL, TER_SL, MAG_SL and TRDS_SL when users had long surface profiles consisting of several dozens of layers. In the POST method, data is no longer a part of the URL string and this restriction is removed, although GID_SL itself still has a restriction of 5000 layers in the profile.
   
  
• Templates for scripted access to GID_SL using the POST method added too.
   
  
• An implementation of POST method for TER_SL, MAG_SL and TRDS_SL should follow shortly.
   
  

• Cobalt Iron Silicide (Co2FeSi) crystal structure was added to the crystals database. Thanks to Bernd Jenichen from the Paul Drude Institute, Berlin, Germany.
   
  

• Fixed a bug in Javascript-based verification of X-Server web forms (the feature introduced 2011/04). The bug reported by Alexander Kazimirov from CHESS was resulted in blocking all X-Server programs in Internet Explorer 8. Please note that with a variety of available web browsers it is hard to guarantee Javascript functionality for any combination of web broser and operating system. Most of X-Server testing has been performed with Mozilla Firefox. Besides of Javascript issues, Internet Explorer is not recommended because it may truncate submitted profiles in all XXX_sl programs (see log record of 2003/04/08). In case of task submition issues please try another browser. Also please report the problems to the author so that they could be resolved promptly.
   
  

• Modified webforms for all X-Server programs so that they bypass inputs disabling when a browser has Javascript disabled.
   
  

• Added energy scanning to GID_sl.
   
  
• Added automatic disabling unused inputs and pre-check for limits on used inputs in the WWW forms for TRDS_sl and MAG_sl.
   
  

• Added automatic disabling unused inputs and pre-check for limits on used inputs in the WWW forms for TER_sl.
   
  

• Added automatic disabling unused inputs and pre-check for limits on used inputs in the WWW forms for X0h and X0h_search.
   
  

• Added an option to specify X-ray wavelength via Bragg angle in GID_sl.
   
  
• Added automatic disabling unused inputs and pre-check for limits on used inputs in the WWW forms for GID_sl.
   
  
• Added a sample WWW form for GID_sl demonstrating how to specify geometries with Bragg angles close to 90-degrees.
   
  

• A new structure La(.5)Sr(1.5)MnO4 has been added to the crystals database. Thanks to Dr. Clemens von Korff Schmising from Lund University, Sweden.
   
  

• A bug in the X0h code has been fixed. The bug could cause usage of the X0h DB data instead of Henke and Cowan-Brennan data at higher X-ray energies even when the Henke or Cowan-Brennan were selected. Thanks to Ondrej Caha from Masaryk University, Czech Republic for communicating the problem.
   
  

• A new structure MgAl2O4 (Magnesium Aluminate Spinel) has been added to the crystals database. Thanks to Anna Kossoy (LANL).
   
  

• The room-temperature Debye coefficient for Silicon has been changed from B=0.556 to B=0.480 as per Acta Cryst. 1996 A52, 456-470. Thanks to Johannes Will from the University of Erlagen for providing the reference.
   
  

• A new structure Sapphire_hex (Sapphire crystal in hexagonal setting) has been added to the crystals database. The previosly existed Sapphire structure in the rhombohedral setting was renamed into Sapphire_rhomb. Thanks to Steven Huband at the University of Warwick for the submission of Sapphire_hex.
   
  

• Three new structures: Gd3Ga5O12, Gd3Sc2Ga3O12 and Y3Al5O12 (YAG) have been added to the crystals database. Thanks to David Walker, University of Warwick.
   
  
• A new structure: LiTaO3 has been added to the crystals database. Thanks to Steven Huband, University of Warwick.
   
  

• A bug in the structure listing utility was found that had been preventing the web forms to show all available structures in the X0h database. Thanks to Dmitry Novikov from DESY (Hamburg, Germany) for pointing out the problem.
   
  

• Two new structures: PbTe and PbSe have been added to the crystals database. Thanks to Eugen Wintersberger, University of Linz.
   
  

• Anti-spam protection was added to all web forms in order to prevent spammers from posting nasty links and messages on X-ray Server. Unfortunately, it imposed certain inconveniences on legitime users: please do not include any links and unusual comments into the surface layer profiles of GID_sl, MAG_sl, TER_sl, and TRDS_sl programs, for example something like this:

  ; this data was taken from https://www.abcde.edu
  

  or this:

  ; this is a GOOD idea!
  ; EXCELLENT program
  ; I like this SITE!
  ; HEY, it is COOL!
  ; THANKS to your work!
  

  Words printed above in CAPITAL letters are examples of what may trigger the protection. Please remove them from surface layer profiles if your submission got rejected.
   
  

• A bug in the X0h interpolation algorithm that was introduced on 2006/11/27 (see the note below in this log) has been fixed. X0h deploys Don Cromer's interpolation formula as the main algorithm for calculating dispersion corrections df' and df". At high energies this algorithm may become unstable. Additional logic has been added that compares results of different interpolation methods and discards the Don Cromer-style interpolation when it diverges. Thanks to Dr. Gianfranco Zosi from Universita di Torino for noticing and reporting the problem.
   
  

• Three new structures: CaRuO3, CaMnO3, and LaAlO3 have been added to the crystals database. Thanks to John Freeland, APS.
   
  

• GID_SL, MAG_SL and TER_SL have been supplied with the control for the maximum number of parallel tasks (currently 4 for GID_SL and 5 for MAG_SL and TER_SL). In case the limit is exceeded, the client receives a message like this:

          NN instances of GID_sl are already being processed by the Server.
          Please submit jour job at a later time.
  

  In case of using scripting, one may want to update the script with analyzing the return page for these above phrase and then resubmitting the job after a small delay.
   
   
  
• The X-Ray Server now prints the job ID on the HTML page before starting calculations with GID_SL, MAG_SL, TER_SL or TRDS_SL. The ID appears at the top of the page as:

          Job ID: GIDxxxxx.
  

  Then, even if a timeout happens, one can still retrieve the job results by sending the following request to the server:

          https://x-server.gmca.aps.anl.gov/cgi/wwwwatch.pl?jobname=gidnnnnn
  

  
   
  

• X0h has been updated to self-check the applicability of the Wagenfeld method for X_i0 and X_ih. The Wagenfeld method [G.Hildebrandt, J.D.Stephenson, and H.Wagenfeld -- Z.Naturforschung, vol.30a (1975) p.697-707] is used in X0h for elements with Z from 9 to 54 in the medium-energy X-ray range when an automatic or "X0h" database option is selected. It has been a preferred method in X0h over using the dispersion corrections df" from the Henke or Cowan-Brennan tables because it gives the quadruple cross-sections of X-ray absorption. The later is important for correct description of the anomalous X-ray transmission (the Borrmann effect) since in the Borrmann effect the dipole contributions are suppressed by the interference.
   
  However, as recently reported by Steve Johnson (the Swiss Light Source), the Wagenfeld method may give too high absorption for Tellurium (Z=52) compared to more modern tables by Henke and Cowan-Brennan. This may also be the case with some other elements.
   
  To avoid these discrepancies, the following self-diagnostics has been added to the calculations using the Wagenfeld method: if the df" given by this method differs by more than 25% from the standard tables, X0h opts to use df" from the tables (Henke, Cowan-Brennan or International Tables) and sets the quadruple contribution to zero. Whenever such an event occurs, the output of X0h web interface will contain a warning message.
   
  Some other warning messages about non-critical X0h problem have also been added, especially about problems interpolating the dispersion corrections df" from the tabular values at given X-ray wavelengths.
   
  All the other X-server programs depending on X0h have been updated too, but in their case warnings are not displayed.
   
  

• Four new structures: Sr3Ti2O7, Sr2TiO4, Sr4Ti3O10, and PbMg.24Nb.48Ti.28O3r have been added to the crystals database. Thanks to Ines Pommrich, TU Dresden, Germany.
   
  

• Two more example scripts added to the automated access page. The scripts demonstrate access to the TRDS_SL and MAG_SL programs from a remote client software.
   
  
• The plotting routine that presents calculated data as PNG plot was corrected to calculate correct intensity limits in the linear scale.
   
  

• Two new structures: KTiOPO4 and Tellurium-I have been added to the crystals database. Thanks to Joerg Goettlicher, Forschungszentrum Karlsruhe, and Steve Johnson, Swiss Light Source, respectively.
   
  

• Automated access page and example automation scripts introduced.
   
  

• Two new structures: 0.74[Pb(Mg1/3Nb2/3)O3]-0.26PbTiO3 and 0.71[Pb(Mg1/3Nb2/3)O3]-0.29PbTiO3 have been added to the crystals database. The structures submitted by Ines Pommrich, TU Dresden, Germany and are after A.K. Singh and D. Pandey, Phys. Rev. B67, 064102 (2003).
   
  

• Two bugs were fixed in X0h. The bugs could cause loss of X-ray wavelength in some combinations of input parameters (the program would complain: no wavelength data) and did not allow using reflections with the Bragg angle of 90 degrees.
   
  

• Several example scripts have been made available to demonstrate advanced interaction with X0h. Read more about the advanced interaction at the X0h home page.
   
  

• X0h extended to print X-ray absorption depth in the symmetric Laue case. Three parameters are calculated: the absorption depth far from the Bragg peak and the absorption depth at the Bragg peak for both Borrmann (anomalously transmitted) and anti-Borrmann (anomalously absorbed) X-ray wavefields respectively.
   
  
• An option was added to generate X0h output in a text form. This was done to simplify scripting interface to X0h. Some examples of scripting interface are on the way.
   
  
• A checkbox was added to print atomic coordinates in X0h.
   
  

• Standing waves calculations added to TER_SL. The standing waves can be used to analyze secondary photo emission effects like fluorescence, the formation of periodic wavefields inside multilayers, the Yoneda effect, and etc.
   
  

• The control over the alpha_max parameter in the GID_SL program has been released to users. See the help on the alpha_max parameter referred from all the GID_SL forms. Thanks to Ming Zhong from the Texas A&M University for helpful discussion.
   
  

• Two bugs have been fixed in the code building incident wavevector for GID_SL. The bugs could occur at the Bragg angles close to 90 degr. and in some modes of specifying the diffraction geometry when the incident angle of X-ray beam was not given in degrees.
   
  
• A new version of GID_SL released. The new code can dynamically switch to treating a crystalline layer as amorphous when the Bragg deviation alpha=(k+h)^2-k^2 exceeds certain threshold. This avoids attempts to calculate very weak reflections since the intensity of Bragg reflection decreases as 1/alpha^2 and weak reflections may cause numerical errors. At present the threshold is set as alpha_max=10,000; that correspond to ignoring the layer reflectivity below 1/10^8. If all the layers in the target are far from their Bragg condition, the threshold is not enforced on the layer(s) with a minimum |alpha| among all the layers. The currently existing web interface does not have the option for changing alpha_max by remote users. but such an option may be added in the future, if requested.
   
  

• Praseodymium Oxide (Pr2O3) crystal structure has been added to the crystals database. Thanks to Bernd Jenichen from the Paul Drude Institute, Berlin, Germany.
   
  

• Several bugs have been fixed in BRL and MAG_sl programs. The bugs could cause the programs to crash under certain input conditions.
   
  

• Tungsten crystal structure has been added to the crystals database. Thanks to Adriana Rueda from the Institute for Nuclear Physics, University of Mainz, Germany.
   
  

• Several bugs have been fixed in BRL and MAG_sl programs. The bugs could cause the programs to crash under certain input conditions.
   
  

• A bug has been fixed in the web interface to the BRL program. The input filter did not detect multiple forbidden reflections that could not be indirectly excited (the Renninger effect) and therefore were resulted in singular scattering matrix.
   
  

• A new organic crystal structure called C9H10N2 has been added to the X0h database. The data is due to Markus Braun and Peter Gilch. The C9H10N2 has monoclinic symmetry and Z=4. Please note that the H-atoms are not included into the structure. Since scattering from hydrogen is low, the error should be small.
   
  

• The GaN structure was corrected -- thanks to the communication by XianRong Huang from the State University of New York at Stony Brook. The Wurtzite-type hexagonal structure of GaN must have 2 atoms of each kind per unit cell, while previously the structure contained in the X0h database specified 2 extra atoms of Ga and N due to mistaken submission by one the X-Ray Server users.
   
  
• A metastable version of GaN called GaN_cubic has been added to the X0h database. This is a Zinc-Blende-type structure with cubic symmetry.
   
  
• The input filter of the GID_sl program was updated to detect non-physical input where Im(xh) > Im(x0).
   
  

• A bug has been fixed in checking duplicate keywords the MAG_sl program. The bug could cause erroneous reporting of duplicate layer thickness 't=' in the surface layer profile.
   
  

• Two new structures -- LaMnO3 and La(.7)Sr(.3)MnO3 -- have been added to the crystals database. The structures data were submitted by Alexander Levin from the Technical University of Dresden, Germany. The former structure is cubic with Pm-3m symmetry (space group #221) while the latter is trigonal (R-3cH, #167).
   
  

• A bug has been fixed in the web interface to the BRL program. The bug was preventing the x-ray line type input of x-ray data to BRL.
   
  
• A minor bug has been fixed in the MAG_sl program. The bug was causing incorrect output in the error report about too thick transition layer.
   
  

• The MAG_sl page has been updated with more detailed program guide. Thanks to the comments by Sunil Sinha (University of California at San Diego) and Dongryeol Lee (APS).
   
  

• A bug has been fixed in the web interface to the BRL program. The bug was preventing the wavelength-type input of x-ray data to BRL.
   
  

• The MnAs structure has been added to the crystals database -- thanks to Dillip Kumar Satapathy from the Paul Drude Institute, Berlin, Germany. The structure describes MnAs below Tc =318 K. This ia a ferromagnetic metal with NiAs-type unit cell (space group #194; two atoms of each type in the cell).
   
  

• A bug has been fixed in the way TER_sl and GID_sl were treating the x0r input. The matter is that the sign of x0r depends on the choice of exponent representing x-ray waves in the media. One can present the waves as either exp(ikr) or exp(-ikr) and both of these choices can be found in the literature. The X-ray Server programs follow the exp(ikr) notation and for them one expects x0r < 0. Therefore, to avoid any confusion, both TER_sl and GID_sl converted the x0r input into -|x0r|. However, this did not cover some absorption edges in the soft x-ray region where apparently x0r may change its sign. Now, the input has been made more flexible: normally the x0r is still converted into -|x0r| but if the edge=1 flag is specified for a layer, the x0r data for this layer is used as entered. The above pertains to the manual specification of x0r; the data automatically calculated by the X0h system based on the material code are not converted. There is a restriction that one cannot manually specify x0r with inverted sign for the substrate in TER_sl and MAG_sl programs. In this case you he may use a thick "buffer" layer so that the substrate becomes unreachable for x-rays. I thank Bryan Barnes, a graduate student from the University of Wisconsin whose communication lead to the above improvement.
   
  

• Two new programs have been made available online at the X-ray Server. The MAG_sl calculates x-ray resonant specular reflection from magnetic multilayers with interface roughness and transition layers and the BRL calculates multiple Bragg diffraction of x-rays by perfect crystals (up to 12-wave case). This has been a major change in the past 4 year. Most of the other Server programs had to be modified as well in order to make the new stuff working. Therefore, be alert of possible bugs and instabilities. Any reports will be appreciated.
   
  

• The 3D-maps are finally implemented for displaying maps of diffuse scattering in the TRDS_SL program. This has become possible due to upgrading to the new experimental version 3.8.0 of GNUplot that supports the 3D mapping functionality.
   
  

• A problem has been identified with the Microsoft Internet Explorer (potentially it might exits some other browsers too -- see below):
  When the submission string is long (exceeds ~1 kilobyte), Internet Explorer either submits an incomplete string (silently truncates submitted string to 1KB) or the "Submit Query" button stops responding (the behavior depends on the version of IE). This may happen when users design some long surface profiles to the GID_SL, TER_SL, MAG_SL and TRDS_SL programs. In those cases, when the profile is received incomplete, those programs would generate an error about incorrect profile syntax, although on user's side the profile may look correct. To check that you are facing such a problem, download respective ZIPped logs back from the server and inspect the PRF file inside it.
  The problem has not been observed with Firefox, SeaMonkey and Netscape browsers and at present the only workaround to the problem is to use those browsers. The behaviour of Opera and Google Chrome has not been tested.
  Another possible workaround could be implementing the "profile upload" functionality into the web form, so that user could upload a prepared file with profile data. However, at present it is not considered because of potential cyber security risks.
   
  

• The Auricupride structure, Cu3Au has been added to the crystals database -- thanks to Dmitry Novikov from DESY (Hamburg, Germany).
   
  

• A stupid bug is fixed in the html form produced by the X0h program. The bug did not allow to call the Bragg curves from the X0h results page.
   
  

• The Ni crystal structure Nickel has been added to the crystals database -- thanks to Samantha Warren from ESRF.
   
  

• A bug is fixed in the html form produced by the X0h program. When one was trying to request the specular reflectivity or the Bragg curves from that form, the request was directed to the old location of the site: sergey.bio.aps.anl.gov. Thanks to Ivan Vartaniants from the University of Illinois at Urbana Champaign.
   
  

• All the server programs were re-compiled using a new faster Compaq Fortran compiler. This should improve the calculation speed but please be alert of possible compatibility bugs.
   
  

• The server was essentially down for about a week due to a bug introduced in the database while adding a new structure. Since I was away on vacation, this could not be fixed immediately...
   
  

• Two new hexagonal structures SiC-4H and SiC-6H have been added to the crystals database -- thanks to Alain Declemy from the University de Poitiers, France.
   
  

• Two bugs are corrected in the way the X0h program calculates the extinction length and the FWHM of Bragg peaks -- thanks to Terry Jach from NIST.
  • The first bug was that |Xh| in the expressions for the extinction length and the FWHM of Bragg peaks needed to be replaced by the |sqrt(Xh*X-h)|. The old formula was valid for centrosymmetric crystals but could give a few percent error for non-centrosymmetric ones.
     
    
  • The second bug was that the Laue-case extinction length was calculated the same way as the Bragg case one although commonly their definitions differ by the factor of PI=3.14. At the same time the X0h help screen was correct which might be a source of confusion. Now after the formula is corrected, the Laue-case extinction length of the old X0h printouts needs to be multiplied by PI to get the new values and vice versa.
     
    

• The Bragg planes search tool is added to the X0h page. The tool provides services often required for planning x-ray diffraction experiments, like searching for all strong Bragg-case reflections, or extremely asymmetric Bragg reflections, etc.
   
  

• The WWW-accessed UNZIP utility is added to the server. This utility unpacks the results of calculations on users' requests, so that downloading ZIPped results of GID_SL, TER_SL, and TRDS_SL is no longer the only option as before.
   
  

• Four simplified interfaces for defining coplanar diffraction geometries were added to the GID_sl program. With the new interfaces the specification of crystal surface is no longer required and the geometry is defined by either the incidence angle of k0, or the exit angle of kh, or the angle of Bragg planes to the surface, or the asymmetry parameter beta=g0/gh.
   
  
• Two new templates were added to the GID_sl page that provide the access to the simplified interfaces.
   
  
• More help on building the diffraction geometry and choosing the scan axes was added to the GID_sl page and respective templates.
   
  

• A bug fixed in GID_sl, TER_sl and TRDS_sl: the surface layer profile lines with empty space followed by the comment symbols ("!" or ";") are now ignored. The previous versions of the programs discarded only those lines where the symbols "!" or ";" stayed in the first column.
   
  

• This LOG page was added.
   
  
• The Web server ported to Apache, so that now it can run on UNIX platforms too.
   
  
• All of the programs handling users requests have been updated to the CGI-1.1 from WinCGI used before with the previous Web server (Tahiti-Beta). The CGI-1.1 is a more commonly used protocol than WinCGI and using it can simplify moving the server from the Windows platform to a more productive UNIX workstation (such a possibility is currently under consideration).
   
  
• All of the x-ray data request forms have been made dynamic: now they are generated on the fly by a CGI script which includes into them the most recent data from the X0h database.
   
  
• Links have been added to all of the x-ray data request forms to call the help screens displaying information about available materials in the X0h database.
   
  
• The GID_sl program has been updated to handle the back diffraction case (the case of Bragg angles close to 90^o).
   
  
• X0h_form now additionally displays the Laue-case extinction length and the FWHM of double-crystal rocking curves.
   
  
• Two popup help screens have been added to the X0h_form. These screens show the equations used to calculate the parameters presented by the X0h_form.