X-Ray Shields & Collimating Devices

 Shield Header

PMI manufactures a line of x-ray shielding products that represent a significant improvement from the traditional components that historically have been used to provide collimation, radiation shielding and scatter reduction. Standard and custom products include x-ray tube mounts, x-ray attenuation shields, HV receptacle shields, rotor shields, primary collimators, radiation stops and blades and x-ray scatter reduction devices.

These devices improve x-ray imaging resolution by reducing the negative effects of scattered x-ray and unwanted x-ray leakage. They are preferred over products that either contains lead or lead-compounds for both attenuation and shielding properties where hazardous material and safety compliance issues are of concern. In addition, the excellent electrical insulating property the use of plastic provides results in improved high voltage operation.

PMI formulates materials specifically designed for radiation shielding applications where close proximity to HV components is necessary. A variety of materials are compounded for both prototype designs and production manufacturing. PMI formulations are ideal for intricate parts design. Mounting inserts and other component parts can be encapsulated in the molding process.

Physical properties include resistance to mineral oil and most hydrocarbons up to a 155-degC service temperature, and can be used to provide mechanical support to the x-ray tube insert.

Specific gravity formulations range from 4.0 to 11.0.

 

PMI EPOXY CASTABLE X-RAY SHIELDS

This data sheet lists the properties of a single formulation satisfying the shielding requirements for many x-ray tube housing assemblies.  As noted, the shields retain electrical insulative properties for reducing the intensity of high voltage stress and enhance overall high voltage performance.

The H1780 X-Ray Absorption of Lead vs. H1780 X-Ray Shield Material curve illustrates the x-ray absorptive characteristics of H1780 compared to lead for energies of 80 and 120 KVP.  It is shown that H1780 has about one-third the x-ray absorption of lead.  (See Graph Below)

H1780 Rev 01 Epoxy Castable X-Ray Shield Material

Typical Cured Properties  
  • Specific Gravity (g/cc)
  • Hardness, shore D
  • Tensile Strength (psi)
  • Compressive Strength @25oC, psi
  • Service Temperature, oC

4.5
90
8,100
13,200
-60 to 155

Typical Thermal Properties  
  • Thermal Conductivity, W/mK
  • Coeffecient of Thermal Exp, in/in/oCx10-6
  • Thermal Resistance @ oC/in/W
 .3
38
128
Typical Electrical Properties  
  • Volume Resistivity @ 25oC, ohm-cm
  • Dielectric Constant @ 25oC, 100KC
  • Dissipation Factor @ 25oC, 100KC
  • Dielectric Strength, volts/mil
1015
4.1
0.02
400-500
Color Yellow-Green
Toxicity RoHS Compliant Pending

 Disclaimer:  These properties were determined by laboratory testing and although the values are believed to be correct and typical, the should serve only as a guide.  Actual property evaluation and suitability for a particular purpose may require other specified tests.  Each user must identify and perform all tests and analyses necessary to assure that its finished parts using PMI products will be safe and suitable for use under end-use conditions.  Each user bears full responsibility for making its own determination as to the suitability of PMI Products, recommendations, or advice for its own particular use.

 

Assortment of shields that PMI currently manufactures
U.S. Patent 6,320,936 X-Ray Tube Assembly with Beam Limiting Device for Reducing Off-Focus Radiation applies.
X-Ray Absorption of Lead vs. H1780 X-Ray Shield Material