Patent GB-903894-A (GB)
Title: Improvements in supports for x-ray diffractometers
IPC: G01N23/207
Filed: 1961-02-28
Abstract: 903,894. X-ray diffractometers. PICKER X-RAY CORPORATION WAITE MANUFACTURING DIVISION Inc. Feb. 28, 1961 [Feb. 29, 1960], No. 7318/61. Class 98 (1). An X-ray diffractometer comprises a tubular support member secured to the lower wall of a hollow casing, a rotatable sleeve surrounding it, a second rotatable sleeve surrounding the first, the sleeves being adapted at their upper ends for mounting thereon a detector, or a specimen under analysis, or an X- ray tube, the casing also housing means for driving the two sleeves. As shown, the hollow casing 10 has top and bottom walls 11, 12, one plane side-wall 15 and the other side-wall formed in two parts 16, 17 slightly inclined towards each other. The upper wall 11 is in two sections lla and 11b which are independently removable. A tubular support 21 is bolted to the lower wall 12, and projects through an opening 20 in it. An inner sleeve 25 is journalled on the outer surface of support 22, and an outer sleeve 31 journalled round the inner sleeve. The inner sleeve is connected to a specimen support 35 which carries a specimen 36. Attached to the outer sleeve is a mounting ring 42 having a radially projecting arm 37 on which is mounted a detector 38 and slit mechanism 39. The sleeves are rotated by worm gearing 41, 44 and 40, 43 respectively. The main drive motor 63 is connected through a gear train 64 and a clutch 80 to a main drive shaft 65. This drives worm 22 directly through pinions 70, 71 and worm 43 through a differential 72, so designed that worm 43 rotates at half the speed of worm 44. Thus the specimen 36 will be rotated at half the speed of the detector 38. A further motor 73 is connected to the differential 72 and to a specimen positionindicating shaft 76. If this motor is operating, only the worm 43 is driven, the main drive shaft 65 and worm 44 remaining stationary. To facilitate initial setting up, the motors 63, 73 may be disconnected by respective clutches 80, 81 and the worm gears rotated by turning hand cranks 91, 92 attached to respective indicator knobs 66, 77 on the ends of shafts 65, 76 respectively. The section 11b of the upper wall carries a rectangular X-ray tube housing 45 having a square end 47 of reduced section. This is pivotally supported on a Z-shaped bracket 48, and the tube can be turned about this pivot 51 by an adjustment screw 52 in order to al the focal spot on the specimen. The X-ray tube can also be adjusted in two directions at right-angles by adjustment means (Figs. 7 and 9, not shown). Fig. 11 shows in detail the shutter assembly generally designated 115 in Fig. 1. A mounting plate 116 is fixed to one face of the square anode end 47 of the X-ray tube, and on the plate is slidably mounted the shutter member 117, which can be moved so that the part 120 covers the tube window 53 to block emission of X-rays. Light from lamps 114 operated by the X-ray tube power generator can be seen through holes 118 in the plate 116, thus indicating whether the shutter is open or not before the X-ray tube itself is energized. If the shutter is closed, arms 119 on the latter will block the holes 118. The shutter can be opened manually, or by a solenoid, and latched in the open position. Secured to the mounting plate 116 is a filter retainer plate 126 carrying a wheel 127, the wheel having three windows 130 each holding a different X-ray filter element; the wheel can be turned to bring any one of the filters into alignment with the X-ray beam. The plate 126 also carries a further adjustably attached plate 135 which has an annular recess 139 for receiving a collimator. Four such shutters may be mounted round the four faces of the square end 47 of the X-ray tube. In the arrangement of Fig. 13 (not shown), two such diffractometers are positioned to operate with a single X-ray tube. A further study, e.g. a diffraction camera, may be set up in alignment with another window of the tube, so that three studies may be in progress at the same time. In Fig. 14 (not shown), the device is mounted on a vertical wall, and the specimen is within an evacuated cover. In this form, the specimen is fixed, while the detector and the X-ray tube are mounted respectively on the two rotatable sleeves. In Fig. 15 (not shown), the specimen is of radioactive material and is brought from a storage position to the operative position by a simple elevator. In this case, the detector is fixed, the X-ray tube and the specimen being movably mounted.