Protocol for starting the SAXS accessories before starting SAXS.

 

  1. Start the chiller (check the chiller set temp is 25°C). The pump and compressor are working properly
  2. Switch on the power supply to the computer, Perkin Elmer Cyclotron, Vaccum pump, Temperature Controller Unit (TCU – 50) and Water pump( Thermo Haako). The switches are marked on the switch board.
  3. Set the temperature of the sample by selecting appropriate temperature in TCU – 50 and press start button

 

Starting the SAXS instrument

 

  1. Push and hold the the Power On button on the Philips control panel of the SAXS instrument till you see all the LEDs glow.
  2. Make entry into the Log book by filling columns appropriately.
  3. Turn the HT meter key to ON position and wait till the display is 20 KV – 10 mA and the OK led glows
  4. Slowly, in steps of five units, increase the current and voltage alternately, starting with current first, to 40 kV – 40 mA using the + buttons of the HT meter.
  5. Always ensure that the OK LED is glowing. Incase the OK led is off please wait till it glows again. Make the increments gradual and slow at a rate of one unit per two seconds approximately.
  6. Open the needle valve to release the vacuum slowly and steadily
  7. Open the sample insertion lock and load the sample.
  8. Put image plate in appropriate position by sliding it through the groove. Ensure always that the cut side of the plate is always on top and the X-Ray sensitive side (Blue side) faces the sample.
  9. Replace the locker and turn it clock-wise. It is a pressure locking mechanism and do not force any mechanical parts.
  10. Close the needle valve and switch on the vacuum pump by pressing “START/STOP” press-button on the vacuum pump display panel
  11. Program the shutter

 

How to program the shutter?

 

This is an example for programming shutter # 4 to open for 1 hour, 2 mins and 30 sec.

 

  1. Select the shutter by pressing the shutter select push button switch until the shutter # 4 is displayed.
  2. Press the hrs/min/sec pushbutton switch until the hrs digits are blinking in the display (Program mode).
  3. Press the Time set switch + or – pushbutton switch until the hrs digits read 01. Each time this switch is pressed the time will advance or decreases one increment. If the switch is held for at least 2 seconds, the time will increase at a rapid rate for as long as the button is depressed.
  4. Press the hrs/min/sec pushbutton switch until the min digits are blinking in the display (Program mode)
  5. Press the Time set switch + or – pushbutton switch until the min digits read 02. Each time this switch is pressed the time will advance or decreases one increment. If the switch is held for at least 2 seconds, the time will increase at a rapid rate for as long as the button is depressed.
  6. Press the hrs/min/sec pushbutton switch until the sec digits are blinking in the display (Program mode)
  7. Press the Time set switch + or – pushbutton switch until the min digits read 30. Each time this switch is pressed the time will advance or decreases one increment. If the switch is held for at least 2 seconds, the time will increase at a rapid rate for as long as the button is depressed.
  8. Confirm the display reads – (shutter) # 4 = (status) CLOSED ( Timer ) 01 – 02 – 30
  9. Press the hrs/min/sec pushbutton switch one final time and see that all the digits are in a steady state. Press the Assign pushbutton switch for shutter # 4.
  10. Press the Shutter open enable pushbutton switch and open # 4 switch. Simultaneously and observe shutter # 4 OPEN and Timer starts counting down. Also observe that the green light in the Assign pushbutton is illuminated.
  11. Read the Image Plate

 

Once the timer has counted down to 00-00-00, the shutter will close and after 2 seconds, the timer program will return to its programmed setting (01-02-30).

 

If the shutter is to be closed in the middle of the experiment due to some reason it can be done using CLOSE pushbutton. IF a shutter is closed while “Assigned”, the timer will reset to the original setting. A shutter can be “disassigned” by pressing ∞ and it will remain open indefinitely until manually closed. If a shutter is disassigned and then re-assigned, the timer will start at the original setting that was programmed for that particular shutter.

 

 

Reading the image plate

 

  1. Start the cyclotron with the carrousel inside it. Always ensure that the pins of the carrousel are normal to the center.
  2. Start the computer.
  3. Open OptiQuant software. Click instruments in the tool bar at the top.
  4. The cyclotron gets initialized and then a virtual grid of carrousel cut-open view is seen.
  5. Select the area to be scanned by selecting a mask stored mask as per SAXS or WAXS experiment done.
  6. Shutter closes after counting down to 00-00-00. Then release the vacuum by turning the needle valve slowly and steadily.
  7. After the vacuum reading is atmospheric, make the room dark and remove the image plate. Note replace the lid on the SAXS immediately after the plate is removed.
  8. Clamp the plate in the carrousel using the pins in the dark room. Release the pins once the plate is in position
  9. Put the carrousel into the cyclotron and then close its lid
  10. Click the start button on the OptiQuant software of the initialized instrument window.
  11. The selected area is scanned and a ‘tif’ image of it is produced.
  12. Open the ‘tif’ image in SaxsQuant  software and integrate the intensity data to get a I Vs q  plot.
  13. Process the plot and save it as a ‘.PDH’ file (Primary Data Handling)

 

 

 

Instrument shut down.

 

  1. Release vacuum and remove sample holder from the SAXS instrument.
  2. Replace the sample locker.
  3. Remove the image plate.
  4. Close the needle valve and start vacuum
  5. Decrease the voltage and current values of HT to 20 and 10 in steps of 5 units gradually, starting with voltage at a rate of 1 unit per 2 seconds.
  6. When the panel reads 20 kV and 10 mA turn the HT key OFF.
  7. Make entry into the Log Book.
  8. Push the Power Off button the panel to turn the power off.
  9. Shut down the computer and then switch off the cyclotron.
  10. Stop vaccum and switch off the TCU and ThermoHaako.
  11. Turn all the switches on the switch board off.
  12. Remove the sample from the sample holder and clean thoroughly. Incase of liquid holders a prolonged cleaning session with Millipore water is required.
  13. Turn the Chiller Off.

 

 

Check list before leaving the room

 

  1. Carrousel pins are in normal position.
  2. All instruments are off.
  3. All plates are on the eraser.
  4. Sample holders and other accessories back in the box.
  5. Sample removed from the sample holder.
  6. Sample holder properly cleaned.
  7. Log book entry done.
  8. Computer shutdown.