These products consist of a very uniform deposit of blue-emitting P22 type silver activated zinc sulfide phosphor (ZnS:Ag) applied to one side of a backing material. They are specifically intended for alpha particle detection, and the phosphor layer density is sufficient to completely absorb common alpha particles such as those from 241Am. Batch to batch uniformity of alpha sensitivity is constant within a ± 1.5% range. The phosphor layer is smooth and sufficiently robust to withstand normal handling.
EJ-440 consists of ZnS:Ag phosphor applied to a clear polyester plastic sheet. The sheets are quite flexible and can easily be cut with scissors or a paper cutter.
EJ-442 consists of ZnS:Ag phosphor applied to one side of a thick, non-flexible support material. This product is custom-made to satisfy each customer's specific requirements. The most common support materials are acrylic plates, but metal support plates have also been used. These materials are very stable, and their shelf life at room temperature is at least two years.
Light Output (% Anthracene)
Wavelength of Maximum Emission (nm)
Decay Time (ns)
Phosphor Density (mg/cm2)
3.25 ± 0.25
EJ-440, Thickness of Polyester Film (mm)
EJ-440, Density of Polyester Film (mg/cm2)
The adhesive is soluble in common alcohols and other organic solvents. It is insoluble in water.