PSPC/MDG 2000 X-RAY MICRODIFFRACTOMETER. Product Information

Transcription

1 THE RIGAKU JOURNAL VOL. 11 I NO.2 I 1994 Product Information X-RAY MICRODIFFRACTOMETER PSPC/MDG Introduction The analysis of X-ray diffraction patterns is well known as an effective means of obtaining information on the state of extremely small areas of crystals. However, the X-ray intensities obtained from such areas by X-ray diffraction are extremely low and do not generally produce uniform Debye rings of a typical powder diffraction pattern. The PSPC/MDG 2000 is specifically designed to realize such measurements and analyses. It utilizes the following components to achieve these goals. (1) A position sensitive proportional counter (curved PSPC) which permits simultaneous detection of all reflections over the entire 20 measurement range. (2) A unique oscillation mechanism which allows triple-orthogonal axis sample motions to improve the randomization of the diffraction pattern, even with single crystal-like samples. (3) A detector arrangement and movement to facilitate sample insertion and removal. (4) A zoom optical microscope with X-V-Z adjusting stage to enable easy sample positioning for 10 flm diameter X-ray spot irradiation. (5) All systems computer controlled using a multi-user multi-tasking EWS on a UNIXbased host computer. (6) Plentiful options such as automatic X-V sample translation stage, total reflection collimators, a television monitoring system for sample observation. Software options include packages for residual stress, reflection pole figure analysis, preferred orientation calculations, etc. The PSPC/MDG 2000 thus embodies a system configuration which is capable of collecting abundant high quality data on microscopic areas of a sample! Vol. 11 No

2 2. Features (1) Sample insertion and removal are simplified, as the detector is located at the top of the instrument and can be retracted as necessary. (2) The detector is equipped with a translation mechanism to permit resetting for the wide 28 angular range. (3) The X-ray optical axis is easily adjusted by measuring the direct beam intensity using a pinhole slit. (4) Thin film measurements at low angles, residual stress measurements at high angles and reflection pole figure measurement at low or high angles can be made thanks in part to the wide to, x, and 28 angular ranges, thus providing even richer information and higher quality analysis. (5) Sample positioning is improved with the zoom optical microscope coupled with the manual X-V-Z axis adjusting function. (6) The sample thickness can be up to 30 mm maximum to enable non-destructive measurement of selected portions of a large test piece. (7) Improved analytical results are ensured by utilizing a variety of options, including an automatic X-V sample translation stage, a total reflection collimator, etc. 3. Configuration I~rved PSPC LSPC-150C) Position analysis (PAD) Goniometer w. x. Automatic X-Y sample sliding stage (option) L----I Water circulating pump 4. Instrumentation 4.1 Goniometer Scanning Axis (1) 28 angle (with curved PSPC-150C) Range settings Measurement range: 150 (simultaneous operation) Manual movement Range is adjustable by up to (2) waxis Oscillation range 5-90 (minimum (3) X axis Oscillation range 5-90 (minimum (4) cp axis Oscillation range (minimum Full spinning allowed. Note: the cp axis control limits with the automated X-V sample translation stage (option) are: Setting range: ± 180 (minimum Oscillation range: ±180 (minimum Full spinning not allowed. The Rigaku Journal

3 4.1.2 Sample Positioning Mechanism X-V axis motion: Stroke 6 mm (with micrometer control) Z axis Stroke 30 mm Note: The stroke for Z differs depending on the oscillation angle. For w motions below 60, the full 30 mm stroke is available. For w motions to 90, the stroke is 10 mm Standard Sample A standard sample of crystalline silicon powder is supplied for alignment and calibration purposes Collimators Metal collimators: 0.01, 0.03, 0.05, 0.10 mm diameter 0.10 mm diameter (for alignment) Optical Microscope Crosshair positioning Oblique Illumination AlignmentJig Pinhole slit: 0.03 mm diameter Fluorescent screen (for checking area of irradiation) Measurement Method Data can be collected in transmission or reflection mode Optional Equipment (1) Total reflection Collimator: A total reflection capillary is used as an incident collimator to increase the intensity of the incident X-rays. The relative intensity at the sample position is at least two times greater than the intensity from the standard collimators. (2) Automated X-V sample translation stage: The X-V stage is controlled by the host computer to permit automatic (with stepper motor) mapping measurements of the sample surface. (3) Television system for sample observation: The sample can be observed on a television monitor when the microscope is equipped with a camera. 4.2 Detector System Curved PSPC-150C (1) "Camera length": 82.5mm (detector radius) (2) Measurement range: 150 (3) Window height: 10 mm (4) Incident window: Be (5) Position resolution: Below 0.2 FWHM (measured with 0.05 mm wide CrKa) (6) Position linearity: Better than ± 1% (7) Counting Efficiency: 60% (for CrKa) 36% (for CuKa) Gas System (1) Gas Composition: Gas cylinder: Regulator Ar 90%, CH 4 10% 7000 liters 2-stage pressure control & primary/secondary metering, 22 mm diameter-14 thread, clockwise male screw (2) Flow monitor: Liquid bubble trap Position Analyzing Device (PAD) (1) Amplifier Bipolar out Shaping functions: a to ±12 V maximum a to 10V, 12V maximum 2 stage differential 1 stage active filter Gain Coarse-x 10, X30, x 100, X300, x 1 K, xs K. FinexO.3to X1.0 (2) TSCA Negative out Positive out Delay Discriminator: (3) TAC (start) : (stop) : TAC, Out a to ± 12V maximum 20 nsec crossover timing pulse width 0.5 usee crossover timing pulse width 0.2 to 2.3 usee Baseline-0.1 to 10 V Window-O.O to 10 V (4) HV Out: a to 5000 V (5) Pulse Out: a to 5 V, 500 Hz (6) Ratemeter Time Constant: Range Voltage :5-250 mv Voltage :5-250 mv a to 10 V (pulse height proportional to time difference between start and stop signals) TTL logic 0.5, 1,2 sec 100, 1 K, 10 K, 100 K, TEST (TEST range with pulser on-1 K) (7) Power Supply: 100V AC, ±10%, 2A Multichannel Analyzer (MCA) (1) ADC (signal converter from analog to digital) A-D conversion signal method: 100 MHz, Wilkinson Method Positive unipolar pulse or preceding positive bipolar pulse. AC or DC coupling Vol. 11 No

4 impedance Discriminator Conversion Conversion time gain Integral linearity selectable. voltage-o to 8 V. 1 xn Lower and upper levels-o to 10 V (PT+0.01N+0.5) usee where PT is time up to the input pulse peak and N is the number of the converted channel (for 8 V input) Within ±0.05% (5 to 100% full scale) Differential linearity: Within ±0.05% Zero adjustment Gate input SCA output Dead time display Digital offset Gate Output SCA Output (5 to 100% full scale) ±3-4% of full scale TTL level pulse DIP switch±selection Positive TTL logic pulse at start of conversion Percent display of mean value of time shown on LCD screen during ADC run o to 3968 channels, 128 channels/step TTL level output "High" level in stop mode "Low" level in all other modes Signal output of single channel analyzer (2) Control/Memory Operations Operating functions (set by key-strokes or external control) START/STOP ERASE ZOOM Memory size MemoryQlock. Conversion.qain OFFSET FlJ.LL'SCALE 10 2 to 10 7 $TOP MODE. OFF/TIME/COUNT O~ERATION MODE: ADD/SUBTRACT TIME MODE DISPLAY MODE PRESET TIME PRESET COUNT READ/WRITE Measurement start/stop Erase data in memory Magnify data displayed 4096 o to 15 (maximum block number-4096-:- memory size) 4096 (for 8 V input) o to 3968 (in 128 channel steps) L1VE/TRUE DOTS/LINES 1 to sec 1 to counts Readout and writing of measuring conditions and data (3) Communications Systems GP-IB (binary 4 bytes fixed format) and RS- 232C (ASCII format) are provided as standard. (4) Memory Size Channel capacity Memory size 4096 channels _1 Counting capacity : Single cycle time : 600 nsec (5) CPU (C-MOS): 10 MHz (6) Display Unit Real time display of measured profiles LCD. Display unit: 200x640 DPI, LCD back lighted 96(H)X189(W) mm dimensions (7) Power Supply: 100V AC ±10%, 5A 4.3 Controller Hardware (1) CPU: 6809,2 MHz (2) Axis Controls: Each stepping motor for to, X' ~ and for X, Y translation (option) (3) Control Mode: Automatic mode (through host computer control) Manual mode (on-board hand switches) (4) Shutter Control: Shutter open/close manually or by host computer (5) Communications System: Through RS-232C interface Power Requirements: 100V AC ±10%,5A 4.4 Software PSPC Control (1) PSPC Software: For goniometer, MCA control and data collection (2) Data Collection Method: Selection of channel/intensity or angle/ intensity data Optional Software (1) Qualitative Analysis: Using angie/intensity data measured on.4.2 The Rigaku Journal

5 with PSPCsoftware (2) Residual Stress: Measurement of reflections and data processing (3) Preferred Orientation: Measurement and data processing (4) X-V Intensity Mapping: Measurement and data processing 5. Measurement Examples 5.1 Effects of Triple-Axis Oscillations A comparison was made between data collected on a sample run with and without oscillation. An aluminum thin film was deposited on a lui4al 0% CU FILM NO OSC ~ 1 91 single crystal silicon substrate. In the case of no oscillation, the thin film shows an intense but highly preferred orientation diffraction pattern, making phase identification extremely difficult. For the diffraction pattern taken which the sample was oscillated, the "random" pattern indicating the aluminum coating is clearly visible, as well as diffraction lines for the single crystal silicon substrate. 5.2 Effects of Total Reflection Collimator A three to four times increase in beam intensity can be realized by using a total reflection capillary in place of the ordinary pinhole collimator. This significantly improves the signal-tonoise ratio making it easy to detect very small peaks that are difficult to observe with the ordinary collimator. (a) Sample held stationary 0 ~ " <l> ';; s ;:: LL I CURSOR{chl: 0.CDUN!: 200il 27G{,----, (a) Standard collimator lum AL 0% cui 3-AXIS OSC ~ 1 91 (b) Sample oscillated CHANNEL 2017 CURSOR{d,): [) COllin: zeoe IB198r ;, , (b) Total reflection capillary '" I ( )...J1!, I!;JJ lul...ul I L I I, CHANNEL Vol. 11 No