This page is a CGI interface to my program TER_sl simulating x-ray specular reflection from multilayers with the account for interface roughness or transition layers. The method implemented in TER_sl is the recursive matrix algorithm (RMA) developed for grazing-incidence x-ray diffraction. The RMA is neither Parratt's nor Abeles', although it can be reduced to each of them. The advantage of RMA is that the same code works for both the diffraction and reflection problems.
Starting July 2005 the program can also calculate and print the intensity of standing waves inside the target. 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.
This short guide provides some explanations on the TER_sl data input and outlines the restrictions of this Web interface.
The TER_sl program is executed on my PC, which runs a Web server under Windows operating system. Since this PC is shared by all of the WEB users of my x-ray library, please, avoid overloading the server by running multiple tasks at the same time.
To obtain the results from TER_sl you need to fill out the input form and click on the SUBMIT button. If your input is correct, the results will be presented as a figure and a reference to downloadable ZIP file with the data. Otherwise, an error report will be returned.
The specification of surface layer profile is implemented with a simple script language. A typical syntax is:
; comments are allowed in any line, but should not contain special symbols like '"*?$!@% period=5 t=10 code=GaAs w0=0.8 sigma=2 t=10 code=GaAs x=0.3 code2=AlAs x2=0.7 sigma=2 t=10 code=SiGe rho=0.9 sigma=2 t=10 x0=(5e-4,7e-6) tr=5 t=10 w0=.5 tr=4 t=10 w0=0.5 t=10 end period
x0=w0*x0By default, this factor is equal to one. Unlike usual Debye-Waller factor, w0 can be greater than one, because it is simply one more way to specify x0.
Here is a practical example -- a profile for 20-period AlAs/GaAs superlattice with 100 Angstroms of GaAs and 70 Angstroms of AlAs in each period; the structure is covered by additional 200A of GaAs and, finally, there is some 20A amorphous oxide layer on the surface:
; Oxide layer: t=20. w0=0.7 ; -- w0=0.7 because of reduced layer density ; Cap layer: t=200. ; -- when the code is not specified, the substrate code (GaAs) is used ; Superlattice: period=20 t=100. t=70. code=AlAs end period
For the rest of parameters you are suggested to follow the common sense. To ensure that your input was correct, please verify respective listing file -- a file with the ".TBL" extension in the ZIPped archive referred from the TER_sl results screen.
To simplify understanding the TER_sl you are provided the templates
listed below. All the templates link to the same program and provide
the same functionality. They differ by preloaded data to demonstrate some
possible applications of TER_sl.
Besides, when submitting the TER_sl task, it is possible to check the progress watching option. The progress watching is obviously more comfortable, but it might not work with some old Web browsers. Also, it is a bit slower because of putting an additional load on the network and launching each 5 seconds a watch program on my computer. Welcome to try both of the ways and choose the most convenient for your needs.
New of April-2012: POST-Method Templates
This is an older, but better tested method. Generally it works very well except for
known problems with IE browser & some firewalls for structure description exceeding 2K bytes.
Here is a tool to retrieve the results of finished jobs if you know the job ID. Some possible uses of this tool are: