How to run the experiment on A1

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Station computers
 
On the  data collection computer:
log in as "specuser", if necessary, the password is available from the CHESS and MacCHESS personnel;
check the disk space available for data collection and create the directory with PI's name;
type "start_ccd" in the terminal window to start data collection program, you may also double click on the "MacCHESS" icon.
 
On the hardware control computer:
log in, if necessary, as "specuser" using the same password;
press the "MacCHESS" icon to start Rspec program: "OpsTerm@a1.chess.cornell.edu" and "CHESS spec functions", each on its own window.
   
Make sure there is a beam passing through the collimator.
In the "OpsTerm@a1 window" type:
opens - to check the counts by opening the shutter in front of the collimator;
closes - to close the shutter;
if counts are low, align the optical table using the "Quick Table Alignment" button on the "CHESS spec functions" window.
   
In the "CHESS spec functions" window use:
Quick Table Alignment - this is the alignment to use in most cases. Make fine adjustments to the optical table to align the collimator with the beam and to maximize counts through the collimator. If counts do not return to previous value, call CHESS operator for help. If you are getting the messages "define_table" or "set_table_zero", follow the instructions and press "Define Table" or "Set Table Zero" buttons found in the "CHESS spec functions" window. Equivalently, you may type command "quick_align" in the "OpsTerm@a1" window.
Set Table Zero - this must be done whenever the motors that control the table position have been moved for some reason, i.e. not through "align_table" or "quick_align" macros. This command defines the current optical table position to be the zero position.
Define Table - enter optical table parameters. You will be asked for parameters. Normally, you will accept the default (standard table) values. Press OK.
Interrupt Spec - stops motor motions immediately and returns the optical table to the original position. Equivalent to typing "abort" in the "OpsTerm@a1" window. 
   
Crystal centering
 
On the data collection computer open terminal window and type "start_centering" to bring up automatic crystal centering program or double click on the icon:
double click on the crystal in order to bring the crystal to the crosshair;
rotate the spindle 90 degrees and double click on the crystal again and so on;
rotate the crystal 360 degrees to insure perfect centering.
   
If you have problems centering the crystal, please go to  "Crystal centering problems" or ask for help.
   
Data collection
   
Close the hutch door and raise the safety shield in front of the CCD detector:
press the black button on the control panel and make sure green "Garage door" light is on;
if the shield does not move, check:
  if there is a beam through the collimator;
  if the beam stop is in place;
     
Remember to raise the safety shield every time you close the door in the hutch!
 
Project setup (optional): on data collection software program use Setup/Project to enter file names, etc. ADX will create a subdirectory for you, if necessary, but not multiple levels of directories.
 
Snapshot Mode: use Setup/Snapshot to take a test exposure from your crystal. Take more exposures, if necessary, to optimize the data collection parameters:
make sure you tell the program to take a new dark current with the exposure time that you have selected;
the first snapshot will start up an ADXV display process; for display of multiple snapshots, keep ADXV running;
rotate the crystal by entering a new phi value;
set direct beam position parameters:
  press Edit/Settings;
  press on "Pick Center" button;
  set the mouse pointer at the beam center and double click;
  use arrows for fine adjustment of the direct beam center position;
  Pick3 button provides a method of setting the beam center by selecting 3 points with the left mouse button. The 3 points define a circle, and the beam center is assigned to the center of the circle.
there are few options to view and set the resolution rings:
the pre-existing option of 5 uniformly spaced resolution rings has been kept as the 5Ring option;
Anchor1, draws a single resolution ring through a point selected with the left mouse button, the ring is updated as the beam center is moved, but always includes the picked point;
Behenate draws a series of rings corresponding to the low resolution rings of Ag behenate based on dividends of 58.38 Angstroms;
two other menu options for automatic refinement of the ring center and automatic refinement of distance with Ag behenate are not finished and are not active at present.
 
Run Mode: data collection is normally conducted through the "Run" window (press Setup/Run(s)):
for normal data collection in ADX control panel use the "Display" button to turn on the "Follow images" mode, if you do not already have an ADXV window;
check the directory;
set data collection parameters;
check the direct beam position parameters;
start collecting data by activating the "Collect" button;
the program starts the data collection by taking the new dark current image automatically and retakes the background image (optional) every certain period of time (7200 seconds), set this up in "CCD Config" window (press Config/CCD).
 
Data files are corrected while subsequent images are being recorded, and corrected files may be processed during data collection with minimal effect on running. Raw images are saved by default, but if you do not need them:
open "CCD Config" window (press Config/CCD);
uncheck "save raw images" option.
 
The "ADX Status" window shows the current image name, spindle angle, and CCD distance.
 
To interrupt the data collection:
use the ADX control panel function "Stop/After Current Image" and let the oscillation end;
   
To resume the data collection:
in the "Run" window click on "Restart", a new window will appear in which you can enter the Run # and the Frame # at which you wish to restart;
if you give a value lower than the current frame, data files will be deleted so that there is no duplication of files;
 click OK in the "Restart" window;
 
When a run is complete, you can start another by setting parameters in the "Run" window and activating "Collect". For a new crystal repeat from step "Crystal centering".
 
To terminate programs:
type "stop_ccd" in any  window, this stops all processes on data collection computer.
   
See the Troubleshooting guide if you have any problems. Call CHESS operator for help.

 

 

 

  Last updated February, 2008
CHESS NCRR NIH