UHV-EL Reference Standards
for EDS/WDS

Ultra High Vacuum Compatible
Micro and Macro Analysis
Standard for Surface and X-ray Analysis

• UHV (ultrahigh vacuum) compatible (10^-10 torr)
• Suitable for spectral and intensity references for EDS, WDS, EPMA, Auger, XPS, ESCA, etc.
• Custom and standard reference material configurations
• Rectangular or circular retainers holding from 6 to 37 reference standards
• Retainers machined from SS304
• Custom mounting bases available
• Each reference standard is individually and separately:
  prepared from bulk or powdered materials, polished with the most suitable method, and can easily be removed or reinserted into the retainer

Analysis accuracies of 1-2% (relative) are possible only when appropriate standards are used. UHV systems cannot accept commonly available standard sets because of outgassing of mount materials and degradation from electron beam heating. The use of bakelite, plastic or epoxy embedded standards under UHV conditions have prevented accurate analysis. These inaccuracies are caused by compromised vacuum levels and contaminated reference standards. Also, standardless techniques give no indication that some elements may not be accounted for or are present in an oxide phase.

Reference standards supplied with the UHV-EL, which contain only UHV compatible materials, can be used to characterize the transmission of the electron energy analyzer, determine peak shapes, resolution, energies and sensitivity factors.

Since generalized sensitivity factors cannot be used with a reasonable degree of accuracy, even for the same instrument model, it is necessary for these factors to be determined for each unique instrument, on a continuing basis. Conditions will change over time because of peak shift, amplifier settings and spectrometer tolerances.

Design
The retainer is precision machined by numerically controlled tools from stainless steel 304. The round UHV-EL-37 is laser engraved to assist in locating the desired reference standard using electron or optical imaging. All reference standards are precisely referenced within 0.13mm of the top surface. This recess protects the reference standard surfaces from contamination and scratching and also minimizes the possibility of X-ray fluorescence from the retainer. The reference standards, which are of various thicknesses, are retained by SS304 clips which are inserted from the bottom of the mount.

Reference standards are individually sized and polished according to the properties of the material. Cross contamination and smearing is avoided.

If a reference standard surface gets roughened from excessive ion beam sputtering or is too highly oxidized, it can be easily removed and replaced in your laboratory. Tools and clips are provided. If bulk materials are not available for some reference standards, powders are used. They are consolidated with silver flake and the powder grains metallographically polished. Many insulators prepared this way are sufficiently conductive for X-ray and Auger analysis without carbon coating. The silver can be used for reference when determining sensitivity factors.

Shipping
UHV-EL-37 circular retainer reference standards are shipped in a VACU-STORR container. It is optional for other configurations or custom orders.

Retainers

25mm diameter UHV-EL-37

For Configuration, designate Retainer Style and reference standard locations and numbers:
Use the submit form
or, alternatively, print the submit form, fill in the corresponding numbers for elements/compounds and fax it to us at: 530-243-3761.

See below for a list of elements and compounds and their respective order numbers.