Mar300 Image Plate instructions


Before you start: turning on the system

 
The mar300 is connected through a SCSI interface to the controlling computer. For this reason, IT IS IMPORTANT TO TURN THINGS ON IN ORDER:
    1)       Turn on the scanner (the box on top of the rack inside the hutch
    2)       Turn on the computer (if the computer was already on before the scanner was turned on, you will have to reboot the computer, see below)
 

Prepare the measurement session:

 
Use the konqueror file manager to create a directory to hold the acquired data. The path to this directory should be somewhere under the /home/mar300 directory. Please create it at the same level as the other, already existing user directories. By convention these directories are called <inverseDate_user> (e.g. 081023_smith, meaning the beamtime allocated to user Smith, which started on 23 October, 2008).
 
From a terminal window (the program is called konsole), launch the marControl program to start working:
                  $ marControl –setd
 
It is not necessary to change directories in konsole, but if you need to, you use the
command
                  $ cd <the new directory>
and
                  $ cd ..
to go to the upper level directory (note the space before the two dots).

Attention: a colored window will appear in the center of the computer screen during the initializing of the Image Plate. WAIT until this window disappears, and the four bars on the right will all be rosa. ONLY NOW the Image Plate is ready for measuring !

Measuring with the Image Plate: the marControl software

 
This software allows control over all the characteristics of the mar300 scanner through a simple graphical user interface. Use the <set distance> button to set the sample-to-detector distance (in mm) assumed by the scanner. The maximum value is 400, which is what you should set if the camera length is bigger.
 

To measure a sample:

   1)       Click “Collect”, then “single set”. The collection dialog appears.
   2)       Write the directory where the images will be stored
   3)       Choose a sample name (a suffix of the form “_XXX” will be added, with XXX a number)
   4)       Choose the first image number (usually 0)
   5)       Choose the number of images to record
   6)       Choose the  exposure time for each image (integer number, in seconds, min=1)
   7)       Choose the scanning mode:
         a.       mar180uses only the central area of the detector (diameter = 180 mm), and produces 1200x1200pixel images
         b.       mar300uses the whole sensitive area and produces 2000x2000pixel images.
   8)       Leave the Dj values at 0 (we don’t have the goniometer accessory to have the sample automatically rotated)
   9)       Click “Go”
  10)  You can dismiss the summary window that appears immediately.
 

A note about times

 
Each image acquisition has 3 steps:
    1)      Expose sample (open and close the shutter)>
    2)      Scan the data from the image plate
    3)      Erase the image plate to get it ready for the next image.
 
The duration of Step 1 is what you set in the “single set” dialog; the duration of step s 2 and 3 is different depending on the scanning mode:
    - 2 min 13 sec for mar180 mode
    - 3 min 30 sec for mar300 mode
 

Saturation limit

 
The maximum count rate should ALLWAYS stay below 65536 (16 bit).
Superating this limit by a factor of two or more will destroy the reading lamps of the Image plate during the erasing process !!!!
 
 
 

Interruption of a measurement

 
If you made a wrong estimation of the measuring time, and fear to superate the saturation limit: just go to the beamline computer (Tick, i.e. the first one on the left of the image plate computer), and close the photon shutter. Then leave the Image plate finish its cylcle of measuring -> reading -> erasing. DO NEVER use the "abort-button", or the detector will get stuck !
 
If you started multiple exposure in automatic mode, and want to finish after less exposures: just press the button "STOP AFTER IMAGE", and wait that the Image plate finish its cylcle of measuring -> reading -> erasing. DO NEVER use the "abort-button", or the detector will get stuck !
 
 
 

Transferring your data

 
The easiest way to retrieve and process your data is to transfer it from the acquisition computer to another beamline computer (e.g. Idefix, the “big-screen” computer) over the internal beamline network:

     1)      Open a second konqueror window, and write the following address in the address bar:
                                 smb://10.3.51.2/slack/User_data
     2)      Drag and drop your files into this window from the first konqueror window you opened
 
 
Alternatively, you can transfer your data from the ImagePlate computer to the Idefix workstation. There are several shortcuts already set up:

     1) On the desktop, there is an icon titled “connect to mar300”. Double-clicking it will open the connection.
     2) In the Windows Explorer, under the “My Network Places”, you find “000_user_data on Osiris”
     3) You can always search for the ImagePlate computer in the local
 
 

Finishing the measurement session

 
As a security measure, the Image Plate computer cannot be shutdown by users (a supervisor password is needed to perform this operation, the local contact should perform this operation).
 
TURN THINGS OFF IN THE REVERSE ORDER AS YOU TURNED THEM ON:
       -    First the computer
       -    Then the scanner
Ultima modifica il Venerdì, 20 Aprile 2012 11:36