Vacuum Applications - Features of Our Vacuum-Compatible Tilt Sensors

Our Miniature Tilt Sensors are now available in special vacuum-compatible versions for use in synchrotron beamlines and other applications where zero outgassing and tolerance to X-rays are required. These sensors (except Models 755-1326 and 756-1326) can be used in high vacuum or ultra-high vacuum conditions (10-6 to 10-10 Torr).  To order, add the letters VAC after the model number, e.g., 755-1172-VAC, 756-1150-VAC, etc.   Our vacuum-compatible sensors have the following features:

Series 755 and 756 (high-gain and mid-range glass sensor assemblies)

• 304 stainless steel housings with 304 stainless steel cover for protection and for reduction of air circulation and convection
• Kapton (polyimide) insulated wires, 30 AWG.  Wire length of 1 meter is standard; specify longer wires using the part number 79055 and the additional length required.
•  Varian’s Torr Seal vacuum-compatible epoxy is used to mount the glass tilt sensors inside the housings
  

Models 84053 and 84064-02 (alumina sensors with mounting brackets)

• Bare, unanodized aluminum mounting bracket
• Stainless steel mounting screws
• Kapton (polyimide) insulated wires, 30 AWG.  Wire length of 1 meter is standard; specify longer wires using the part number 79055 and the additional length required.
  

Model 59579-02 (wide-angle, unmounted alumina sensor)

• Kapton (polyimide) insulated wires, 30 AWG.  Wire length of 1 meter is standard; specify longer wires using the part number 79055 and the additional length required.

The alumina (ceramic) and glass transducers in our Miniature Tilt Sensor modules are filled with electrolyte at 1 atmosphere pressure and then hermetically sealed.  Their hermetic seal easily supports the 1 atmosphere pressure difference that occurs upon application of an external vacuum.  The only way the transducer housing will leak or outgas is if it is crushed or otherwise damaged.  Most of the electrolytes that we use are ethanol- or methanol-based and contain a low concentration of potassium iodide or another dissolved salt.

In vacuum applications where some outgassing is acceptable, our standard Miniature Tilt Sensors may be used.  These standard sensors, which cost less than the vacuum-compatible versions, use a magnesium silicate cement (Series 755 and 756 only) that contains some free water molecules and have Teflon-insulated wires.  If the sensor will be subjected to radiation levels that will damage the Teflon insulation, Kapton insulation can be used instead.