PHILIPS Table-top X-ray Generator PW 1720 Instruction manual
3-1 3. OPERATION This paragraph describes the method of operating the PW 1720 and the options, such as timers etc., but does not include operating instructions for accessory devices such as cameras and vertical goniometers. The initial installation of the PW 1720 is described in the Service part of the manual. 3.1. INITIAL CHECKS Before switching on the generator, check the following: - Check that HT tank transport fixing screw is removed, see Service installation section.
-2 When the shutter is closed the generator will switch off, unless another shutter is still open in one of the other tube shield positions. Alternatively. the generator can be switched off manually by operating the GENERATOR 0 push-button. All lamps will extinguish. Before the generator is switched off the power to the X-ray tube should be reduced, by first turning the mA control to minimum, and then the kV control.
3-3 3.3.1. With timer control Operation, using a timer, is as follows: 1 . Check that generator kV and mA settings are correct. 2. Determine the exposure time, and set the timer for the required window shutter. The clear plastic cover is rotated until the black pointer is set to the required time (0 to 6), while the centre knob is rotated in a clockwise direction until the required multiplication factor (x1, x10 : seconds, minutes or hours) is against the arrow.
3.5. USE OF WINDOWS The tube shield on the PW 1720 has a window on each of the four sides, see paragraph 2.2. The exit of X-rays is prevented by a blank shutter disc, or by a rotating shutter disc whose exit hole should only be positioned at the window when a camera or goniometer is correctly fitted. In addition, there is a shutter controlled by an electromagnet, which can only operate when a safety circuit is complete, and when two push-buttons are operated simultaneously.
Typical window applications are shown below: Line focus Point focus Powder Debye - Scherrer camera diffractometer Texture Guinier camera goniometer Laue camera Weissenberg Precession camera camera Reciprocal lattice explorer 3.6. CHANGING THE X-RAY TUBE To change the X-ray tube, proceed as follows: 1 . Switch off by pressing the GENERATOR 0 push-button. 2. Turn off the water supply. 3.
3-6 6. Change the filament voltage supply, if necessary, depending on the type of focus. A fine focus tube should have a filament voltage of 8 volts, and broad and normal focus tubes require 10 volts. On later tubes the type of focus is indicated, and in other cases consult the tube instruction card. To change the filament voltage, switch off the unit, open the right-hand side panel by loosening the two Allen screws. The panel is hinged at the bottom.
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