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EJ-440, EJ-442




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) 300
 Wavelength of Maximum Emission (nm) 450
 Decay Time (ns) 200
 Phosphor Density (mg/cm2)  3.25 ± 0.25 
 EJ-440, Thickness of Polyester Film (mm) 0.25
 EJ-440, Density of Polyester Film (mg/cm2
Chemical Compatibility
The adhesive is soluble in common alcohols and other organic solvents. It is insoluble in water. 

  EJ-440 & EJ-442 Emission Spectrum

EJ-440 Standard Sizes

  • 216 mm × 279 mm (8.5 in × 11 in)
  • 305 mm × 305 mm (12 in × 12 in)
  • 38 - 50 mm diameter

Custom sizes are also available.

EJ-442 Standard Sizes

Acrylic Plate:
  • 1.5 - 5 mm thick
Maximum Size:
  • 300 mm × 300 mm

Custom sizes are also available.