SCANNING TUNNELING MICROSCOPE                 
                         STM-MDT-10-90                         
 
                         Scanning Head                         
 
                - atomic resolution in the air                 
                 - easy replace of the tip and the sample                  
 
     Scanning tunneling microscope is used for the  research  of 
conducting surfaces in the air under  the  normal  pressure  and 
temperature. 
 
                Main technical characteristics                 
 
1. Vertical resolution - 0.1 A. 
2. Horizontal resolution - 2 A. 
3  The sample size is up to 10 mm. 
4. Scanning area - 1.5x1.5 mkm. 
5. Tunnel current range - 50 pA -50 nA. 
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6. Bias voltage - -10 V. 
7. Rough mechanical sample approach range - 10 mm. 
8. Driving voltage on ceramic tripod is up to 750 V. 
 
                           Electronics                          
  
     Model  STM-MDT-10-90  electronics  provides  the   complete  
keyboard  control  of   the   scanning   tunneling   microscope. 
Electronics operates with the IBM-PC XT/AT computer with a  help 
of its own interface bus. 
     This  model  is  the   first   one   in   the   family   of 
devices(products of our company) and can be easily modified  for 
the future constructions of the STM scanning heads. 
 
                    Main technical features                    
 
1. Complete computer control. 
2. Provides  main scanning  modes:  Constant  Current,  Constant 
Height, I/S, I/V spectroscopy. 
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3. Tunnel  voltage is in the range of -10 V  with  the  step  of 
5 mV. 
4. Tunnel  current stabilized by the feedback  loop  is  in  the 
range of 50 pA - 50 nA with the step of 50 pA. 
5. Preamplifier  has the sensitivity of 0.2 V/nA with the  noise 
of 5 mV. 
6. Automatic tip sample approach. 
 
         Date Acquisition and Image processing software         
               for Scanning Tunneling Microscope               
                      MDT-MULTI-IMAGE 1.3                      
 
     MDT-MULTI-IMAGE 1.3 is the integrated  media  for  scanning 
control  data acquisition, visualization and  image  processing. 
This software is a part of the STM-MDT-10-90 production. 
 
                     Hardware Requirements                     
 
1. Computer IBM-PC XT/AT with minimum 512 K RAM and DOS 3.00  or 
higher. 
2. EGA/VGA adapter with 256 K RAM. 
3  Microsoft two-button mouse is recommended. 
 
             Data Acquisition and Scanning Control             
 
1. Multiple scanning modes: constant current,  constant  height, 
spectroscopy. Simultaneous  acquisition  of  different  signals: 
topography, current and two external signals. 
2. Real time image of STM data. 
3. Scanning at any angle in XY plane. 
4. Interactive setup of new scanning area. 
5. Complete computer control of the tip sample approach. 
 
                       Image Processing                        
 
1. Flexible graphic screen. Up to four independent windows  with 
different data and image types. 
2. Optimal use of RAM and hard disk provides the opportunity  to 
work with 20 arrays of data simultaneously with the size of each 
area up to 300 K (2 bytes per point). 
3. Multiple image modes: 
   a. "Top view" -color map of surface; 
   b. "3-D" - very fast hidden line plot; 
   c. "Isolones" - lines of equal levels of image. 
4.  A  wide  range  of  interactive  functions  for   the   work 
with image: distance  measuring,   rotation   and   scaling   of 
3-dimage,  zooming, cutting and so on. 
5. System is open  for  user.  You  can  write  your  own  image 
processing and connect it with the integrated media. We give you 
some image processing algorithms which  are  released  as   such 
external programs.