Scintillators for Scanning Electron Microscopes

P47 Scintillators

They are coated with a thin layer of well selected P47 phosphor (Y₁Si₂O₇:Ce3+; yttrium silicate activated with cerium), and have a high signal output and a good working life. They need not be coated with aluminum prior to use unless cathodoluminescence studies are required.

*P-47 is usually in-stock.

YAG Single Crystal Scintillator Discs

Advantages:

• Low Phosphor Noise.
• High Resistance to Radiation Damage.
• Long Working Life.
• Possible Application in Ultrahigh Vacuum Conditions.

YAG (Yttrium Aluminum Garnet activated by Ce3+) has a very fast response time of 50-60ns and they do withstand well to the bombardment by electrons or ions far better than plastic or phosphor scintillators. Light emission peaks at about 560nm which means that S20 photocathodes are most suitable for detecting the emission. YAG is suited for high current operations. The response is better then for the P47 discs below 5kV and again at higher accelerating voltages, where the performance of powder scintillators fall off while the response of the YAG continues to increase linearly.

The crystal should be coated with 50nm of aluminum prior to use. If the layer becomes damaged it can be removed with sodium hydroxide. The crystals are mounted with the matte surface in contact with the light pipe as this has shown to increase the efficiency.

*YAG delivery time is 6-8 weeks..

YAP Single Crystal Scintillator Discs

YAP (Yttrium Aluminum Perovskite activated by Ce3+) shares the same advantages as YAG but is more efficient in terms of light output than YAG crystals. As well, the emission spectrum peaks at about 378nm, and this corresponds closely to the maximum sensitivity of the S11 photocathode which in general is used in most scanning electron microscopes. (There would be more improvement in signal by using a YAP crystal rather than YAG in these microscopes). The decay time of YAP (40ns) is faster than YAG (80ns) so its overall performance is superior to YAG. YAP crystals should be coated with 50nm of aluminum prior to use.

*YAP delivery time is 6-8 weeks..

Light Pipe Scintillators

The light pipe is the connection between the scintillator and the phosphomultiplier tube (PMT). It transfers the photons produced by the scintillator for detection by the PMT. We coat the scintillator material directly on the light pipe which improves the signal. Light Pipes are available in optical quality quartz and optical grade acrylic. Cambridge reduced-tip models are only available in acrylic. High voltage wire and corona ring are included. JEOL pipes include a flange. Price includes one Re-coating Certificate. Re-coating is typically needed twice per year.

SEM Specimen Mounts