• What's New
• XRF Sample Cup Overview
• XRF Sample Cup Selection Guide
• Thin-Film Sample Supports
  • Continuous Rolls/Precut Circles
  • Spectromembrane Thin-Films
• Thin-Film Window Selection Guide
• Sample Cups and Thin-Film Attachment Accessories
• Microporous Film
• Grinding Equipment Overview
• Briquetting Presses
• Briquetting Dies
• Briquetting Cups
• Grinding and Briquetting Additives
• Liquid-Binder Grinding and Briquetting Additive
• Pre-Fused Fusion Fluxes
• Non-aqueous Standards
• New Account/Information Requests

SPECTROCERTIFIED® THIN-FILM XRF SAMPLE CUP WINDOWS

A thin-film window is defined as a substance that is used to retain powdered, liquid, slurry or other types of samples in sample cups for x-ray spectrochemical analysis. To qualify for suitability, the substance must possess specific characteristics: reasonable degrees of chemical attack resistance; sample retention strength; uniformity of thickness; relative freedom of influential trace element impurities; multi-axial to minimize preferred orientation; and relatively high analyte-line transmission values, especially for the less energetic (KeV) or longer wavelengths (Å). The combination of density, gauge and mass attenuation coefficients are the principle factors controlling analyte-line transmission in accordance with Lambert's Law:

I/Io = exp [-(µ/d)(dt)]

Where, I/Io = percent incident and transmitted radiation

µ/d = mass attenuation coefficient

dt = area concentration

Few substances are characterized with all of these properties and explain why there is such a diversity of thin-film windows. All window materials tend to have varying degrees of static electricity. It presents the most troublesome in handling for attachment to sample cups and any clippings from trimming the excess material tend to annoyingly adhere to any nearby objects. The exception is a thin-film integrated in SpectroMembrane Carrier Frames. The most suitable thin-film windows for x-ray applications are: Polyester, Prolene®, Polypropylene, Polyimide (Kapton®), Mylar® and Etnom™ Thin-Films.

Typical Properties of Thin-Film Windows

THIN-FILM TYPE	TYPICAL UNIFORMITY	TRACE IMPURITY LEVEL, PPM	DENSITY, GM/CC	STRUCTURAL FORMULA
Mylar®, Hostaphan®, Polyester	1 - 2% per package; less than 5% between different lots	Ca, P, Sb, Fe, Zn	1.38	C10H8O4
Prolene®, Polypropylene		Ca, P, Fe, Cu, Zr, Ti, Al	0.91	C3H6
EtnomTM		Si, Ca, P, Zn, Sb	1.36	C14H10O4
Polyimide (Kapton®)		None reported of significant value	1.42	C20H10O5N2

	CONTINUOUS ROLLS Thin-film windows in roll form are packaged in serrated edged boxes for ease of dispensing and cutting the required length. Each roll is 3” x 300’ (7.6 cm x 91.4 m). Trimming excess window material after sample cup attachment is generally required.
	PRE-CUT CIRCLES Pre-cut thin-film window circles are 2.5” (6.4 cm) in diameter to minimize or completely eliminate trimming. Each circle is supported on special paper carrier to facilitate handling and minimize contamination. They are available in packages of 500 and 1000 circles.
	SPECTROMEMBRANE® SAMPLE SUPPORT CARRIER FRAMES Thin-film windows with circumscribed perforations are pre-mounted on square carrier frames with center holes to completely eliminate direct handling, contamination and static electricity annoyances. During application, they automatically detach from the frames. Supplied in 3" (76.2 mm) or 2.5" (63.5 mm) thin-film diameters in packages containing 100 SpectroMembrane units.