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 matt surface in contact with the light pipe as this has shown to increase the efficiency.

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.

Converting from P-47? Use YAP and no need to change the PMT!

The best of both worlds: Emission characteristics of a P47 - using the same photomultiplier - plus the durability of the YAG! Made of yttrium aluminum perovskite. the YAP single crystal is a breakthrough in the light output efficiency. Its emitted spectrum peaks at 378nm (close to the S-11's maximum sensitivity). meaning your SEM does not have to be refitted with a more sensitive photomultiplier. And because the decay time of the YAP crystal is faster than the YAG crystal (40ns vs. 80ns). overall performance is significantly improved. All YAP scintillators should be aluminum coated prior to use in an SEM application and therefore. the SPI YAP scintillators come 50 nm aluminum coated as "standard". freeing the customer from the burden of having to apply aluminum and not knowing for sure just how much to apply. If a YAP is desired without the aluminum coating. be sure to state that you want the scintillator uncoated.

But for many users. the real advantage of the single crystal scintillator is that when compared to P-47. the useful life time is essentially forever, and that is because of its high resistance to radiation damage. While we can not guarantee it, far more often than not, the scintillator far outlives the useful lifetime of the SEM.

Other important features

Excellent signal-to-noise ratio.
TV compatible with fast decay time (40ns).
High temperature tolerance. Bakeability to 400 °C.
Easily detects samples high in cathodoluminescence i.e. gallium arsenide.
Atomic number differences of 0.1 on object analysis.
Chemical Formula: YAlO3
Refractive index: 1.82
Bulk density: 4.551
Aluminum coated on polished side

Just select the scintillator and SPI # that is right for your microscope and that is all there is to it!

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.

CdZnTe

Semiconductor single crystals of CdxZn1-xTe (CdZnTe, CZT, Cadmium Zinc Telluride) are important materials for the development of far-infrared, visible light, X-ray detectors, and gamma-ray detectors as medical imaging devices. CdZnTe (CZT, Cadmium Zinc Telluride) radiation detectors have the advantages of a large absorption coefficient, compact size and room temperature operation. Currently used high purity Ge and Si detectors in industry and medical imaging can only work efficiently at the liquid-nitrogen temperature.
There are many examples of the use of CZT (CdZnTe, Cadmium Zinc Telluride) detectors in medical imaging and diagnostics, ranging from simple x-rays carried out in a dentist's office to cardiac angiography, bone densitometry measurements, and the use of nuclear medicine to pinpoint areas of activity within the brain to help characterize conditions such as epilepsy. In addition, the medical imaging community is interested in developing large area CdZnTe (CZT, Cadmium Zinc Telluride) detector arrays.
Cadmium zinc telluride (CdZnTe) has become a key detector technology for hard x-ray and gamma ray astronomy. Astronomers use CZT (CdZnTe, Cadmium Zinc Telluride) arrays to study the origin of high-energy gamma-ray bursts. One class of astronomy instruments will use large area single focal plane array detectors in conjunction with a focusing optic. CZT (CdZnTe, Cadmium Zinc Telluride) is also suited for high-resolution measurements and isotope identification in the nuclear industry and for x-ray radiography applications. The use of single crystal CZT (CdZnTe, Cadmium Zinc Telluride) as the gamma ray detector material has allowed the production of very compact prototype imaging systems. Further applications for CZT (CdZnTe, Cadmium Zinc Telluride) gamma ray detectors include space flight gamma burst instruments, high-energy x-ray astronomy, and international nuclear inspection and safeguarding.