A short manual for the use of D22

This document describes how to set up D22 and gives a short reminder of important commands. There is also help about emergency procedures.

For more details, refer to the D22 Manual and the instrument control program (MAD) manual.

See also the D22 documentation.

• 1. Instrument preparation
• 2. Preparation of data acquisition
• 2.1. Beam-stop adjustment
• 2.2. Determination of the beam centre on the detector
• 2.3. Sample-changer set-up
• 2.4. Transmission measurements
• 3. Data acquisition control commands
• 4. Instrument control
• 5. Data treatment
• 6. LAMP data display and treatment
• 7. Data transfer with ftp or xftp
• 8. Data transfer to diskette

• User information set-up (MAD commands PAR USER, PAR PROPOSAL, PAR TITLE, PAR LOGBOOK, PAR DATE)
• check space left on data disk (MAD command FREE)
• experiment set-up (changer etc., bath)
• wavelength setting (MAD commands WAVELEN or SELECTOR)
• detector distance (MAD command DET), lateral translation (DTR), rotation (DAN)
• collimation (MAD command COLLIMATION, e. g. coll 5.6)
• beamstop choice (MAD command BEAM reserved to LOCAL CONTACTS)
• iris setting (manual; normal setting 30 mm x 40 mm)
• aperture in front of sample
• Set parameters with program PARAME
• MAD command ADJUST if necessary

Put a sheet of teflon (or another strong forward scatterer) into the beam.

Open the beam with the attenuator in place (MAD command ATTenuator In). Start a run. When you are sure that there is no direct beam visible, take the ATTenuator Out.

The MAD commands BX 0 and BY 0 center the beam-stop roughly. Use the commands RUN preset Nosave, ctrl-C ctrl-C, BX and BY alternatingly. Use absolute position values with BX and BY.

On the instrument Macintosh IIcx, run program 3D_ILL. Select one X line (button 1X). Select x:64 with the glider in window 1X (top); delta-Y 128. Set beam-stop vertically using MAD command BY. Select one Y line (button 1Y). Select y:64 with the glider in window 1Y (top); delta-X 128. Set beam-stop horizontally using MAD command BX. Note BX and BY values. Start and store a run of preset 100 or 200 for later control (see page 2).

When leaving option "one X (or Y) line", don't forget to move value back to zero (risk of "bomb"!).

• Use scattering conditions for collimation.
• Move ATTenuator In.
• Remove beam-stop vertically (BY -100) after noting initial value. Open the beam.
• Start and store a single run of preset 100.
• Run det or detci (UNIX) to determine the "centre of gravity" of the scattering.
• Note Xo, Yo values.
• Put beam-stop back to old values.
• ATTenuator Out.

The values of the beamstop position can be entered into the data files with the PAR CENTRE command in MAD.

• Close the beam.
• Put sample changer in place.
• Connect motor and encoder cables ("EX") and cooling and dry-air pipes.
• Select rack plate.
• Modify motor and changer parameters according to rack plate. Use the MAD PARameter CHAnger SET n command or MAD START RACKn, where n is the rack-plate type number.
• ADJUST sets the correct positions using a scanning procedure.

• Close the beam. Collimation ca. 5.6 m. Choose long detector distance (preferably).
• Make sure detector is centred (DTR 0.)
• Move ATTenuator In
• Note beamstop position values (commands BX, BY)
• Remove beam-stop vertically (BY -500).
• Open the beam. START series of measurements.

Don't forget a safe reference measurement (e.g. the aperture or empty cell transmission) with every set of transmissions.

The data acquisition program MAD is normally active in session 1 of the control terminal. Parameter files have to be prepared before using them in commands (page 1).

General: parameter-file: FILE.CMD (.CMD is the default for MAD on SANS instruments)
         n: number of runs
         p: preset
         "sample title": up to 20 characters.
         Characters and numbers in square brackets are optional.

CHECK      file[.cmd] or file.ext
PARAMETER  (sub-menu)
CHANGER    position
PARAMETER SUBTITLE sample_title (20 characters max.)
RUN        [preset_value] [preset_type] [ntimes] [save/nosave]
START      file[.cmd] or file.ext
HELP       help about the system; 
           on the control terminal while in MAD : help about MAD commands

Stop acquisition or running motors by activating the program PCP with ctrl-C, followed by on of the PCP options (option H for Help) or type a second ctrl-C (equivalent to the Kill option of PCP).

• Single runs: MAD commands
  • PARameter SUBtitle sample_name
  • RUN preset T/M n_times Save
• Multiple runs (changer)
  • Use program PARAME (pages 4 and 8) or editor to create a command file.
  • START file.ext.

MAD

• MAD> ATT C n - choose attenuator number n or ATT IN / ATT OUT
• MAD> ADJUST - automatic positioning of sample changer with respect to the beam
• MAD> BX, BY [v] - show beam stop values/ move beam stop to (absolute) value v
• MAD> DET [x] - shows detector position/ moves detector to x meters
• MAD> COLL [x] - shows collimation position/ moves collimation to x meters (use COLL 99 to get alllowed values)
• MAD> CHANGER [n] - controls changer position (moves to position n)
• MAD> PAR CHANGER - sets parameters for sample changers
• MAD> STR [v] - read position/ translate changer or table to v mm
• MAD> WAVELEN - wavelength reading and setting

Some commands can be combined in one line to save execution time, e.g.

     MAD> DET 10 COLL 11
     MAD> BX BY

Other programs

• SACHA - an interactive program for writing MAD command files
• PARAME - sets instrument control parameters (e.g. selector)
• MSP (mad spy) runs on session 2 of the instrument terminal and displays the state of the data acquisition
• LIS - displays information on file transfer

Data treatment is done on our UNIX workstations. Login as d22, password d22d22 and give your user name as requested by the welcome screen (use small letters). If necessary, open a Unix Shell from the Toolchest (topic Desktop).

Small-angle scattering programs for UNIX are described on the ILL WWW pages. They are generally called by the program name:

• rnilp - program creating a log book file
• windet or detci - raw data display
• areg or rnils - azimuthal average
• spolly - manipulation of averaged data (summing, subtraction of background...)
• xpolly - X window version of spolly
• cont - contour maps
• tysp - type stored averaged data
• rplot - plot averaged data
• rguim - standard fits to averaged data (Guinier, Zimm...)

There is a SANS version of the LAMP program for data treatment and display available on the UNIX workstations of the LSS group. Refer to its own manual. We advise you to start lamp logged in as lambda (no password), eventually after a telnet to one of the group's workstations, e.g.

     telnet d22sgi.ill.fr

Log in as lambda (no password) and type the command lamp&.

Lamp will create local files in a directory /d1/people/lambda/USERNAME. Please, don't leave unnecessary files in there.

ftp is the standard unix file transfer protocol. It is described in the manual pages of the workstations (command "man ftp"). We suggest that you use xftp, a graphical-user-interface application that allows one to easily transfer data and other files between the user's computer and a workstation at the ILL using ftp. Type the command
xftp &
on the workstation. In the application window that appears choose the local directory on the left hand side, either by selecting from the content of the "Dir:" button or by using the "Dir" menu on top. Choose "Connect to remote..." in the "Connect" directory on the right hand side. In the box that appears, either select one of the "Recently Referenced Hosts" or type a new "Host Name" (with a > in front, if it is outside the ILL/ESRF site) and a valid "User Name" at the remote host. You will be prompted for the password of the remote user. Consequently, you can select a remote directory like you do with the local one.

Now you can move files from the local to the remote directory by clicking them one by one in the local directory. After having chosen all your files, click the "Copy" button in "Xfer Ops". Acknowledge the question whether you really want to transfer the chosen files, and off they go.

You may also explore the other options of xftp.

Data transfer to diskette is most easily done using "Fetch" on the Macintosh. Open Fetch, e.g. from the Launcher. On the D22 Mac, Fetch is preconfigured to go to the "d22" user zone. Click the "Connect" button in the "New Connection" box. The connection will build up. You just need to go to your subdirectory by double-clicking it in the list under the "d22" button.

You can then select a list of files in the chosen subdirectory and drag it to a diskette (Mac or PC) that you have entered in the drive, or to the desktop of the Mac.

You can also drag whole directories that will be copied automatically with their contents, but make sure that they fit on the destination!