|
|
 |
index|primer|user
guide|PD macro|CLAM|system|SR
Computing Group
PD Macro User Guide
Contents
* PINCER Primer, M.C.Miller, August 1998.
* PINCER User Guide, M.C.Miller, C.Marshall and H.Millington, August
1998.
* PD Macro User Guide, M.C.Miller, C.C.Tang and E.J.Maclean, August
1998.
* CLAM and 4circle Macro User Guide, M.C.Miller and S.P.Collins, August
1998.
* PINCER System Guide, M.C.Miller, August 1998.
* PINCER Configuration Guide, M.C.Miller, August 1998.
See http://www.dl.ac.uk/SRS/XRD/pincer.dir for html and pdf on-line
versions
The following description of the PD macros is taken from those running on
SRS station 2.3. On other stations there may be options which are not active
but they are retained to provide a familiar interface for users. On some stations,
particularly the Energy Dispersive Powder Diffraction stations, there may be
other options which are not described below but are needed for special scans
and operations involving data collected using a solid state detector and multichannel
analyser (MCA) for example. These are well known to the local station
scientist involved and some help is provided in the PD main menu (in macro
files pd.mac and pdlist.mac).
The instrument parameters in pdinit.mac by default are correct for
the dummy PINCER operation using PD. For real systems settings will need to
be modified and the table below explaining the existing values should give
enough information for this.
top of page
| Line in default pdinit.mac
|
explanation |
| if (nargin!=0||nargout!=0) |
using inbuilt variables nargin and nargout
check for any input and output variables in call to pdinit |
| argerror |
invalid argument(s) given in pdinit call so
call error handling macro argerror.mac |
| end
|
end of "if" command block |
| pdclear |
remove all PD varables by calling macro pdclear |
| global$ stn_name="Station tst" |
declare global string variable stn_name which
is used for graphics title |
| global$ current_motor="a" |
declare global string containing default motor
name for "drive" menu |
| global$ current_mono="SI" |
declare global string containing name of mono
type used in "mono" menu |
| global$ valid_motors="a b" |
declare global string containing list of motors
names separated by a space. Used in PD drive and scan. Must be st in
mot parameter files also (see below) |
| global$ motor_units="stp deg" |
declare global string containing a unit name
list for each motor name in valid_motors string. Should match units set
in mot_gen.dat motor parameter file. |
| global$ motspeed="Default Speed" |
declare global string containing speed setting
status string. |
| global setspeed=0 |
declare global numeric variable indicating
speed setting disabled (0) or enabled (1) |
| global$ th2th_motors="a b" |
declare global string containing 2 motors treated
as theta and twotheta in th2th and Nth2th scans |
| global$ mono_motor="b" |
declare global string containing name of mono
motor for mono menu |
| global$ fmtdef="%#9.4f" |
declare global string containing default format
string for drive motor display (here a total field of 9 characters with
4 decimal places and left aligned) |
| %global$ pdfmt1="%#9.2f slits rot1 rot2
trans" |
commented out declaration of global string
containing 1st alternative format string and motors which
should use it (overrides fmtdef list) |
| %global$ pdfmt2="%#9.3f chi phi" |
commented out declaration of global string
containing 2nd alternative format string and motors which
should use it (overrides fmtdef list) |
| global$ timechan="ch1" |
declare global string containing name string
of timing read channel for read detectors, drive and scans. Must be set
in ctr parameter files |
| global$ monchan="ch2" |
declare global string containing name string
of 1st detector read channel for read detectors, drive and
scans. Must be set in ctr parameter files |
| global$ sparechan="ch3" |
declare global string containing name string
of 2nd detector read channel for read detectors, drive and
scans. Must be set in ctr parameter files |
| global$ detchan="ch4" |
declare global string containing name string
of 3rd detector read channel for read detectors, drive and scans. Must
be set in ctr parameter files |
| global$ timerchan="timer" |
declare global string containing name string
of timer channel for setting count interval. Used in read detectors,
drive and scans. Must be set in ctr parameter files |
| global$ temchan1="ox1" |
declare global string containing 1st temperature
controller name. Can be enabled in pdconfig.dat |
| global$ temchan2="ox2" |
declare global string containing 2nd temperature
controller name. Can be enabled in pdconfig.dat |
| global$ logfile="pd.log" |
declare global string containing path to PD
log file name |
| global$ configfile="pdconfig.dat" |
declare global string containing path to PD
configuration file pdconfig.dat |
| global$ grdev="vgw" |
declare global string containing graphics device
name (vga for DOS or vgw for Windows) |
| global srsfile=-1 |
declare global internal variable for file i/o |
| global ymax_lim=100 |
declare global variable containing default
ymax graph limit in plots |
| global nosrsheadprompt=0 |
declare global internal variable for file i/o |
| global ctr_plot_chan=4 |
declare global internal variable for no. of
counter-timer channel to plot in scan graphics |
| global$ srsfilename="" |
declare global internal string to hold last
SRS datafile name |
| global pd_options[32] |
declare global array which will contain PD
parameters read from pdconfig.dat file |
| readconf = pd_options |
call macro readconf.mac to load pdconfig.dat
parameters to pd_options array |
| init |
call macro init.mac to initialise any hardware
needed by PD |
| setspd "slow" |
call macro setspd.mac to change speed to slow
(only active if enabled elswhere) |
| return |
return to previous macro back to PINCER prompt |
| % |
comment |
| % valid_motors and valid_motors1 will appear
in drive menu and |
comment |
| % scan menu. valid_motors2 will not but
can be set so as to |
comment |
| % have a 2nd drive menu. |
comment |
| % |
comment |
| % stn_name should be set to length 11 characters
for neatness |
comment |
top of page
This file stores the internal parameter settings that PD requires at run-time.
It contains only values and no comments so is modified using 2 other macros
as follows from the PINCER prompt (i.e. outside the PD menus) :
1. type pdconf to give a full list of parameters with their meaning
and instructions on how to modify them.
2. type stdconf for powder diffraction experiments where sensible groups
of parameters can be changed for common modes of operation (see Station
2.3 manual).
In either case restarting the PD macros afterwards will result in the changed
parameters immediately coming into effect.
1. Graph plotting during theta/2 theta scan ON
2. ctrl B action during theta/2 theta scans MENU
3. Graph plotting during ordinary scans ON
4. ctrl B action during ordinary scans MENU
5. Graph plotting during time scans ON
6. ctrl B action during ordinary scans MENU
7. beam down delay (sec) theta/2 theta scan (0=disable) 2700
8. SRS scan file format is POD
9. cryostat being used ON
10. LOG scale on graph DISABLE
11. Auto-rescale during theta/2 theta scans ON
12. Auto-rescale during ordinary scans ON
13. Auto-rescale during time scans ON
14. use read motor position in theta/2 theta scans YES
15. collision detection NONE
16. Save theta/2 theta data in SRS file YES
17. Save scan data in SRS file YES
18. Save read detector data in SRS file YES
19. Allow turbo mode in theta/2 theta scan NO
20. beam down delay (secs) ordinary scans (0=disable) 0
21. monitor rate limit for pausing scans (cps) 50
22. write MATLAB strings to output file YES
23. automatically transfer SRS file YES
24. read MCA data NO
select option to change or 0 to exit opt=8=
Enter number and change option accordingly. However, if data file is intended
for Rietveld refinement you must enter POD for option 8; angles will
be saved in mdeg., and NO for option 22; no MATLAB strings
will be written in data files. If USUAL is entered for option 8; angles
will be saved in degree.
D macros
To leave the PD macros in a controlled way, the main menu option QUIT should
be entered at the correct time. This allows user Pincer functions to be entered
directly at the > prompt. To interrupt a scan or other running option in
a controlled way (but not while a prompt for input is displayed on the screen),
enter <CTRL> B. During a scan, the pause menu
gives access to PINCER commands providing they do not confict with hardware
functions already in use by the paused scan. For an emergency stop use the <CTRL> A sequence
which exits the PD macros completely and requires PD to be entered so they
can be restarted.
top of page
The main powder diffraction macros are collected together, and by entering "PD" the
following menu will appear on the window.
--------------------------------------------------------------
==== POWDER DIFFRACTION MENU ====
OPTIONS ...
Read Read detectors
Drive drive motor menu
Th2th theta-2theta couple scan
NTh2th multiple theta-2theta couple scans
Scan single or two motor scan
NScan multiple scans
Mono monochromator functions
Help help
Quit exit to cli prompt
--------------------------------------------------------------
>>> Enter option="QUIT"
The function of each option is summarised in Table 2. The option required can
be typed in using the upper case character(s) denoted for the command. For read and
other scan options, the data sets are stored in SRS file format.
Table 2. PD commands and functions
| Option |
Function |
| Read
|
Plot out the count rate in one of the three
detector channels as function of time. |
| Drive
|
Allows the user to select one of the motors
which may be driven to a new position or may have its position redefined
to a new value. |
| Th2th
|
Performs one or more coupled theta/2 theta
scans. The user is prompted for the scan range, step size, counting time
and the number of times the scan is to be performed. |
| NTh2th |
Allows the user to perform a number of theta/2
theta scans but the scanning parameters can be set-up individually for
each scan.
|
| Scan
|
Perform a scan of one or two of the motors.
The user is prompted for the scan parameters for each motor. |
| NScan
|
As in Scan but this option allows the scan
parameters to be entered individually for each scan. |
| Mono
|
Allow the user to select or change or set the
x-ray wavelength/energy. |
top of page
To change the wavelength, the user simply types in "Mono" at the PD options
and the following menu will appear:
--------------------------------------------------------------
==== MONO MENU ====
Silicon Monochromator
Monochromator angle ... 11.9688 degrees
Monochromator wavelength ... 1.3004 Angstroms
Monochromator energy ... 9.5353 keV
OPTIONS ...
Deg drive mono to angle (in degrees)
Lam drive mono to wave-length (in angstroms)
Kev drive mono to energy (in keV)
SETANG redefine mono angle
SETLAM redefine mono wave-length
SETKEV redefine mono energy
Quit exit to cli prompt
--------------------------------------------------------------
>>> Enter option="QUIT"
The incident radiation can be selected by typing in either one of the three
commands: Lam for wavelength, Kev for energy or D for angle, followed by the
value. On screen instructions will appear whatever option has been chosen.
Also the monochromator angle, wavelength, or energy can be set using SETANG,
SETLAM or SETKEV respectively.
Warning : Normally, the monochromator is calibrated. The re-setting
of Lam, Kev or Ang must not be performed unless the user is absolutely certain
that the entered value is correct.
Normally the calibrations of [lambda] and 2[theta] are done by the instrument
scientist whenever it is applicable, using up to 9 reflections from an NBS640b
silicon standard powder. When the positions are lost due to computer crash
or power failure or motor crash or any other reason, they needed to be recalibrated.
The procedures as described in the Station 2.3 manual should only be attempted
with the help of the instrument scientist or with someone who has the experience.
A proper calibration should yield a very accurate wavelength (± 0.0001 Å)
and a small 2[theta] offset (<= 0.1°). The values and the associated
uncertainties are recorded in the station log book.
Reflectivity or single crystal experiments require the alignment of the sample
at the centre of rotation of the diffractometer. The software allows individual
motors to be driven when required. The "Drive" option enables the user to perform
such operations. Type in "Drive" or "D" in the Command Window to run the motor
driving macro and the following menu will display:
--------------------------------------------------------------
==== DRIVE MOTOR MENU [Default Speed] ====
DETECTOR ...
channels-> time 1, mon. 20102, spare 0, detec. 512
MOTORS ...
1) tth twotheta : 20.0000 deg 2) ome omega(th): 5.0000 deg
3) mono monochrom: 11.9688 deg 4) slits slits : 0.01 mm
5) table table : 0.0000 mm 6) rot1 gon rot1 : 0.00 deg
7) rot2 gon rot2 : 0.00 deg 8) trans gon tran : 0.76 mm
9) chi crad chi : 90.000 deg 10) phi crad phi : 0.000 deg
11) scat sca slts : 0.0000 mm 12) spare : 0 stp
type motor number or motor name in full
OPTIONS ...
Pos drive to position | SET redefine position
Inc drive by increment | Help help
Att drive attenuator | Jog 1 motor jog
Quit
--------------------------------------------------------------
>>> Enter option="QUIT"=pos <enter>
motor="tth"=ome <enter>
position=5=10.052 <enter>
The motors and definitions are listed in Table 3. The line immediately
below the DETECTORS shows the counts in one second on the monitor and the
detectors. Again, these readings are useful information. By using the pos
command
as shown in the above example, the user has moved the omega circle from
5° to
10.052°. When the move has been completed the computer will update
the motor position in the drive menu, and then invite the user for the
next operation.
Movements can be performed by increments (inc command) as well as
absolute values (pos command). If the positions of these motors need
to be redefined, type in command set and follow on screen instructions.
Caution : Do not reset a motor position unless it is absolutely necessary.
Repetitive increment positioning can be performed using the Jog function.
Type in the command at the drive menu and follow the instructions on the screen.
When the user is finished with this menu, type in Q to get back to
the PD menu. All angular motors turn in degrees and linear translations move
in millimetres.
The user can abort a driving motor by simply clicking the <CTRL-B> or <CTRL-A> button
in the "Pincer Command Window". The first button will abort the drive command
and return back to the menu, while the second button will return back to
the Pincer prompt. The software will retain all motor positions. By restarting
PD menu, all motor positions will be available.
Emergency stop: If all fails press an "EMERGENCY" button to cut
off the power. This operation may lose the motor positions. Emergency buttons
are on the diffractometer, Mclennan unit and in the control gantry.
Table 3. Drive motor commands and functions
| Motor |
Definition and Function |
| tth |
2[theta] axis - allows the user to drive the
two-theta motor |
| ome |
[omega]([theta]) axis - allows the user to
drive the omega motor |
| mono |
[theta]m axis - to move monochromator
(in angle only) |
| slits |
Incident beam slits vertical translation |
| table |
Diffractometer vertical translation |
| rot1 |
Goniometer arc - axis moves about the vertical
plane |
| rot2 |
Goniometer arc - axis moves about the horizontal
plane |
| trans |
Goniometer transitional stage- vertical movement |
| chi |
Large arc on the Euler table |
| phi |
Small circle on the Euler table |
| Att |
Incident beam attenuation wheel with 0, 3,
2, 1, 0.7, 0.24, 0.14 mm thick aluminium absorbers. |
top of page
After sample alignment (may not be necessary for powder work) and instrument
calibration, data collection can commence using an appropriate beam size and
x-ray wavelength. By simply typing in Th2th, Nth2th, Scan or NScan option on
the PD menu, the computer will invite the user for the scan parameters; scan
regions, scan range, step size, counting time and number of scans. As an example,
if the user wishes to perform a [theta]/2[theta] scan from 10° to 120° with
step size of 0.01° and counting time of 2 second per point, the commands
on screen (Command Window) will display as follows;
th <enter>
two theta start [10] : <enter> (default value=10°)
two theta end [11] : 120 <enter> (for 120°)
two theta step [0.01] : (default value=0.01°)
counting time seconds [1] : 2 <enter> (for 2 seconds)
Number of scans with these parameters [1] : <enter> (1 scan)
CONTINUE ? (y/n): [Y] : <enter> (default to start scan)*
>>> Enter title: <enter> (title may be typed in)
>>> Enter condition 1 : <enter>
>>> Enter condition 2 : <enter>
>>> Enter condition 3 : <enter>
The scan parameters, scan number and other information will be displayed on
the Input/Output Window.
Warning : When the computer displays the following message:
Smain warning : Monitor counts are low.
- check X-ray shutter, ports and the SRS beam status!
The warning message means that there are no x-rays in the hutch beam pipe because,
for example, the shutter is still closed. If there are still no x-rays
after the shutter is opened, this means problems further upstream. In that
case, the user should contact the station scientist or personnel in the Main
Control Room for help.
The scan commences when the motors have reached their starting positions, and
the plot of two-theta versus intensity will appear on the "PINCER Graphic Window".
The data will be saved in a file labelled as "r12345.dat" that will appear
at the lower-left of the window. If mistakes were made during the setting up
of the scan, type in N (No) at line indicated by the * above and the
menu will invite the user to re-enter the scan parameters again. Examples of
other scan options are given below. Any time during a scan, it can be interrupted
by pressing <CTRL-B> and waiting for the last scan point to be completed.
This will temporarily suspend the scan and bring up a new menu as follow:
--------------------------------------------------------------
==== SCAN IN PROGRESS MENU ====
OPTIONS ...
use graphics Window to Rescale, Scale and Plot
before printing graph, select the white background
Cli temporary CLI prompt
Abort abort the scan (the data will be save to file)
Quit quit from this menu and continue scan
--------------------------------------------------------------
>>> Enter option="RESCALE"=
The menu above allows the user to change the plot scale or to abort the scan.
The scan remains suspended until the user selects an option from the menu.
The user may type in an option accordingly. By clicking the <CTRL-A> button,
the scan will terminate immediately. Either operation will save the data
in the files. When the scan is finished, another menu will appear as follow:
--------------------------------------------------------------
==== SCAN FINISHED MENU ====
OPTIONS ...
use graphics Window to Rescale, Scale and Plot
before printing graph, select the white background
Info Display san info and statistics
Cli temporary CLI prompt - terminate with `return'
Quit quit menu, and finish
--------------------------------------------------------------
>>> Enter option="QUIT"=
For a hardcopy, the user should use the option in the graphics window and the
plot is dumped on to the Lexmark laser printer placed in the gantry. When option Quit is
entered, the scan is completely finished and the data file will be transferred
automatically (see below).
top of page
With the beam down delay functions switched on (pdconf options 7, 20
and 21), a running scan will pause when the x-ray beam is down as shown in
the example below. Once the beam is back the count down routine will be activated
automatically, and data collection will only resume when the specified delay
time (e.g. 2700 sec) has been reached. The user can terminate the count down
and continue the scan by clicking the <CTRL-B> button and enter option Term as
shown below. Other options are also available.
Beam lost, counting down 2700 secs
SRS file name r12345.dat
--------------------------------------------------------------
==== BEAM MONITORING MENU ====
OPTIONS ...
use graphics Window to Rescale, Scale and Plot
before printing graph, select the white background
Cli temporary CLI prompt - terminate with `return'
Mon continue monitoring beam
Abort abort the scan (the data will be saved to file)
Term terminate count down and continue scan
Quit quit menu, and finish
--------------------------------------------------------------
>>> Enter option="MON"=
1. Put on the Si standard powder (already loaded on a flat-plate holder).
2. Using the jog box inside the hutch drive the omega and two-theta axes to
their zero position with the aid of a spirit level.
3. On the instrument computer set omega and two-theta axes to zero.
4. Set McLennan LED units to zero for both theta and two-theta displays (optional).
5. With the beam on, type in SICALIB at > prompt on the Pincer Command
Window and the computer will ask the following questions.
counting time seconds [1] : <enter>
mono angle error (degree) [1] : <enter>
two theta error (degree) [1] : <enter>
Number of reflections to scan [9] : <enter>
Electron beam current (mA) [ ] : 200 (optional) <enter>
Predicted calibration duration ... 16.1 Minutes
hit key to continue
CONTINUE ? (y/n) : <enter>
>>> Enter condition 1 <enter>
>>> Enter condition 2: <enter>
>>> Enter condition 3: <enter>
File r12345.dat
Warning : When the computer displays the following message:
Smain warning : Monitor counts are low.
- check X-ray shutter, ports and the SRS beam status!
This means that there are no x-rays in the hutch beam pipe because the shutter
is still closed. If there are still no x-rays after the shutter is opened
this means problems further upstream. The user should contact the station scientist
or personnel in the control room for help.
With the x-ray beam on, the diffractometer will scan the first nine Si reflections
when the motors have moved to the starting positions. When the scans are finished,
the following table will be displayed:
Refining wavelength and zero-point
iter lambda (angstroms) two-theta zero
****************************************
1 1.399612 0.007329
2 1.399612 0.007329
****************************************
****************************************
h k l fitted discrepancy
1 1 1 25.7922 -0.0007
2 2 0 42.7485 0.0003
3 1 1 50.6009 0.0006
4 0 0 62.0513 -0.0002
3 3 1 68.3424 0.0004
4 2 2 78.2863 -0.0001
3 3 3 84.0650 0.0005
4 4 0 93.5912 -0.0006
5 3 1 99.3381 -0.0004
****************************************
hardcopy
CONTINUE ? (y/n) : [N] :
recalibrate two-theta axis
CONTINUE ? (y/n) : [N] :
recalibrate monochromator
CONTINUE ? (y/n) : [N] :
The discrepancies in [lambda] and 2[theta] should be small as shown in the
table. Finally, the user needs to answer Y (yes) to calibrate the
wavelength and two theta axis when invited by the macro.
top of page
Theta - 2 Theta scan
two theta start [10] : (default value=10ø)
two theta end [11] : 120 (for 120ø)
counting time seconds [1] : 2 (for 2 seconds)
Number of scans with these parameters [1] : (default=1)
Number of data points . . . 11001
Predicted scan duration . . . 4.3 hours
Plot graph with LOG scale? (y/n) : [N] : (default=No)
CONTINUE ? (y/n): [Y] : (default to start scan)
>>> Enter title: (title may be typed in)
>>> Enter condition 1 :
>>> Enter condition 2 :
>>> Enter condition 3 :
Moving tth to start position 10.00000
Moving tth to start position 5.00000
Scan finished ... File name r12345.dat
SRS file name r12345.dat
The scan will start when the motors have reached the starting positions.
The example below is a scan of the scatter slits from -1 to 1 mm with a step
size of 0.05 mm.
motor="tth"=scat
start1=0=-1
end1=1=1
step1=0.1=0.05
Type in motor2 or <return. for single motor scan [] :
Type in counting time per point in seconds [1] :
Type in channel to be plotted
1 ... Time
2 ... Monitor
3 ... Spare Channel
4 ... 2-theta Arm Detector
channel="4"= (to plot 2-theta detector)
CONTINUE ? (y/n): [Y]: (No, if mistakes were made)
>>> Enter title: (title may be typed in)
>>> Enter condition 1 :
>>> Enter condition 2 :
>>> Enter condition 3 :
File name r12345.dat
Moving scat to start position -1.000
Scan finished ... file name r12345.dat
The scan should start when the motors have reached the starting positions.
******************************
Multiple Theta - 2 Theta Scans
******************************
scan parameters file(or <Enter> to type in scan parameters []:
total number of scans [2] : 3 (for 3 scans)
***********
scan no. 1
***********
two theta start tthst [1]=10=
two theta end tthe[1]=11= 50
two theta step tths[1]=0.01=
counting time seconds sec[1]=1=
***********
scan no. 2
***********
two theta start tthst [2]=50= 50
two theta end tthe[2]=51= 90
two theta step tths[2]=0.01=
counting time seconds sec[2]=1= 5
***********
scan no. 3
***********
two theta start tthst [3]=90=
two theta end tthe[3]=91= 120
two theta step tths[3]=0.01=
counting time seconds sec[3]=1= 10
save each scan in a separate SRS file ? (y/n): [Y] :
Number of scans = 3
tth start tth end tth step count time (secs)
10.000 50.000 0.010 1.000
50.000 90.000 0.010 5.000
90.000 120.000 0.010 10.000
Predicted scan duration ... 19.3 Hours
CONTINUE ? (y/n): [Y] : (default to start scan)
>>> Enter title: <enter> (title may be typed in)
>>> Enter condition 1 :
>>> Enter condition 2 :
>>> Enter condition 3 :
The scans will commence after the motors have reached the starting positions.
The above example shows three [theta]-2[theta] scans that will be executed.
The first scan starts at 10° and ends at 50°, with step size of 0.01° and
counting time of 1 second for each point. The second scan starts at 50° and
ends at 90°, with step size of 0.01° and 5 seconds for each point.
The final scan starts at 90° and ends at 120°, with step size of
0.01° and 10 seconds per point. The three scan data sets will be saved
in separate SRS files.
top of page
**************
Multiple Scans
**************
Motor to move between scans
***************************
motor (or <Enter> to ignore) [] :
nscan=1=10 <Enter> (for 10 repeating scans)
Scan parameters
***************
Number of scans = 10
motor1="tth"=tth
start1=10=
end1=11=120
setp1=0.1=0.01
Type in motor2 or <return> for single motor scan [] :
Type in counting time per point in second [1] : 2
Increment parameters between scans
**********************************
increment counting time by [0] :
increment motor 1 start position by [0] :
increment motor 1 end position by [0] :
execute PINCER command before each scan [] :
execute PINCER command after each scan [] :
Type in channel to be plotted
1 ... Time
2 ... Monitor
3 ... Spare Channel
4 ... 2-theta Arm Detector
channel="4"= (to plot two-theta detector)
Scan 1 of 10
CONTINUE ? (y/n): [Y]:
>>> Enter title: (title may be typed in)
>>> Enter condition 1 :
>>> Enter condition 2 :
>>> Enter condition 3 :
Here, the 2[theta] scan starts at 10° and ends at 120° with step
size of 0.01° and 2 seconds per point. In total, 10 scans will be executed
with the same scan parameters. The first scan will start when the two-theta
motor has reached the starting position. The data of these scans will be saved
in separate SRS files.
top of page
The following data file is an example of a theta/2-theta scan.
&SRS
SRSRUN=25066,SRSDAT=950719,SRSTIM=124048,
SRSSTN='PD23',SRSPRJ='POWDERDF',SRSEXP='12345432',
SRSTLE=' ',
SRSCN1=' ',SRSCN2=' ',SRSCN3=' ',
&END
tth = 44.5000,
ome = 0.0000,
mono = 13.7963,
slits = 0.00,
table = 0.0000,
rot1 = 0.29,
rot2 = -0.27,
trans = 0.00,
chi = 0.000,
phi = 0.000,
Unused = 0,
Unused = 0,
TWOTHETA THETA TIME CHAN2 CHAN3 CHAN4
41600. 20800. 5000. 6497. 0. 66.
41650. 20825. 5000. 6506. 0. 66.
41700. 20850. 5000. 6622. 0. 49.
41750. 20875. 5000. 6479. 0. 64.
41800. 20900. 5000. 6623. 0. 69.
41850. 20925. 5000. 6454. 0. 67.
41900. 20950. 5000. 6503. 0. 67.
41950. 20975. 5000. 6536. 0. 76.
42000. 21000. 5000. 6704. 0. 74.
42050. 21025. 5000. 6564. 0. 60.
42100. 21050. 5000. 6780. 0. 90.
42150. 21075. 5000. 6630. 0. 113.
42200. 21100. 5000. 6583. 0. 117.
42250. 21125. 5000. 6622. 0. 115.
42300. 21150. 5000. 6680. 0. 121.
42350. 21175. 5000. 6717. 0. 128.
42400. 21200. 5000. 6797. 0. 111.
42451. 21225. 5000. 6605. 0. 102.
42500. 21250. 5000. 6583. 0. 83.
42550. 21275. 5000. 6566. 0. 76.
42600. 21300. 5000. 6433. 0. 63.
42650. 21325. 5000. 6559. 0. 65.
42700. 21350. 5000. 6690. 0. 59.
42749. 21375. 5000. 6622. 0. 65.
42800. 21400. 5000. 6588. 0. 51.
42850. 21425. 5000. 6675. 0. 60.
42900. 21450. 5000. 6570. 0. 62.
42950. 21475. 5000. 6497. 0. 57.
43000. 21500. 5000. 6690. 0. 54.
END OF DATA
The first two columns in the above file are the 2[theta] and [theta] values
in mdeg. The subsequent column is collection time (5 sec) per point in milliseconds.
The remaining columns are the counts on the monitor, spare (fluorescence) detector
and the 2[theta] detector. Note that for USUAL configuration, the
angles and time will be in degrees and seconds, respectively.
The following data file is an example of an omega scan.
&SRS
SRSRUN=25065,SRSDAT=950719,SRSTIM=005609,
SRSSTN='PD23',SRSPRJ='POWDERDF',SRSEXP='12345432',
SRSTLE=' ',
SRSCN1=' ',SRSCN2=' ',SRSCN3=' ',
&END
tth = 4.1161,
ome = 2.0982,
mono = 14.8801,
slits = 0.00,
table = 0.0000,
rot1 = 0.00,
rot2 = 0.00,
trans = 0.25,
chi = 0.000,
phi = 0.000,
Unused = 0,
Unused = 0,
ome Time Chan2 Chan3 Chan4
2.0400 1.0000 479. 2301. 269.
2.0410 1.0000 455. 2393. 280.
2.0422 1.0000 452. 2270. 265.
2.0428 1.0000 480. 2349. 269.
2.0442 1.0000 455. 2397. 285.
2.0452 1.0000 475. 2371. 278.
2.0462 1.0000 458. 2303. 249.
2.0470 1.0000 463. 2377. 292.
2.0482 1.0000 464. 2300. 305.
2.0492 1.0000 446. 2334. 296.
2.0500 1.0000 488. 2259. 311.
2.0512 1.0000 492. 2247. 338.
2.0522 1.0000 469. 2389. 427.
2.0530 1.0000 466. 2347. 442.
2.0540 1.0000 482. 2256. 477.
2.0552 1.0000 491. 2334. 597.
2.0560 1.0000 501. 2264. 571.
2.0570 1.0000 484. 2210. 599.
2.0582 1.0000 510. 2203. 572.
2.0592 1.0000 454. 2321. 581.
2.0600 1.0000 478. 2243. 481.
END OF DATA
The data columns are omega (deg.), time (sec), monitor, spare detector and
2[theta] detector readings (counts). Note that for POD configuration,
the angles and time will be in mdeg. and milliseconds, respectively.
top of page
Data files are named rxxxx.dat where xxxxx refers to a unique file number
given to each SRS file on the station. Each successive SRS file created has
a number one larger than the pervious file allowing the data files to be identified.
All data files have the standard SRS header including the run number, date,
time, motor positions and other relevant information. The angle(s), time, monitor
and detector readings are store in columns. The end of the data file is marked
by "END OF DATA".
After each scan, the data file is transferred automatically over the network
to "/srsdata/pd23" directory of xrdsv1 main computer. Sometime the computer
network is down and error messages will appear on screen. These messages are
informative and no action should be taken because the automatic transfer process
will resume once the network is restored. After the files have been transferred,
the data is still present on the instrument PC but the files are renamed with
an extension .con, for example, r12345.dat would become r12345.con after the
transfer. However, the .con files are deleted every now and then in order to
maintain sufficient disk space to run the instrument.
Eventually, the transferred files in "/srsdata/pd23" will be automatically
archived to optical disks. To retrieve these files, log on xrdsv1 and type
in nsrsget pd23 r12345.dat. This will retrieve that particular data
file. For a range of files, type in nsrsget pd23 r12345.dat-r12350.dat.
For more information type in man nsrsget.
top of page
1. "Portable Data Acquisition Software based on a powerful Command Interpreter
and Object Oriented Hardware Control", M.C.Miller, K.Ackroyd and G.Oszlanyi.
Presented at ESONE Real-time Data Conference (RTD94), Dubna, Russia 27th -
31st July 1994 and Daresbury Laboratory Preprint DL/CSE/P29E.
2. "SRS Station 2.3 Manual", C.C.Tang, M.C.Miller, E.J.Maclean. CLRC Technical
Report DL-TR-98-001, March 1998.
3. "A Novel X-ray Diffractometer to Study the Texture of Materials", C.C.Tang,
M.C.Miller, S.M.Clark, M.A.Player and G.R.G.Craib. Accepted for J. Synchrotron
Rad. 1996 (in press).
|
