As I said I used green phosphor from JEOL, cat. # 423-011. Call and see if this number still holds true. You will also need a dish big enough for the screen and a cover (preferably glass) with a small hole for removal of the liquid.

1. Remove the old coating from the screen by washing in acetone. The cleaned plate must be free from all particles of matter and the surface must be free from blemishes and scratches.

2. Prepare a sufficient volume of 4% (w/v) suspension of phosphor powder in acetone containing about 1% collodion. The total volume must be sufficent to fill selected dish with liquid to a depth of about 1cm above the surface of the screen in position on the bottom of the dish.

3. Agitate the suspension vigorously (I used sonicator) then pour it rapidly into the dish.

4. Wait about 5-10 seconds to allow larger particles to settle and swirling to cease.

5. Slide the plate smoothly into the liquid, preferably without scraping the bottom of the dish.

6. Cover the dish and leave to settle. When the suspension has settled and the remaining liquid is clear, draw off the liquid by inserting a suction tube through the previously prepared hole in the lid of the dish. It is extremely important not ot disturb the screen plate or the liquid above it in any way as this is done. Draw off the liquid steadily and slowly then remove the suction tube.

7. Leave the screen to dry without any disturbance of any kind. Do not lift the lid to inspect the screen until the powder is quite dry because a slight change in drying conditions can produce a visible mark on the damp surface.

8. When the powder is quite dry, remove the screen and wipe off any excess phosphor from the back and sides of the screen.

9. Install.

10. A newly coated screen will outgas for a short time when it is first placed in the microscope. Pumping times may therefore be a little longer than normal at first.

A very small particle size is desirable for high resolution screens and it may be advantageous to agitate the the phosphor suspension in an ultrasonicator before putting it into the dish.

Hope this helps. It can get tricky and you may not get it the first time. Patience really helps!

Phil Rutledge