Starna Cuvettes
Material Specifications
Starna® spectrophotometer cells and other complex quartz assemblies, unless precluded by design, are assembled using a fully fused method of construction. This technique, pioneered by Optiglass personnel, ensures that cells are fused into a single homogeneous piece using heat alone, without intermediate bonding materials. All cells are carefully annealed to remove any possible remnants of strain after the fusing process, ensuring that cells achieve maximum physical strength as well as resistance to solvents. With few exceptions, cells can be used safely with pressure differentials of up to Pa (three atmospheres).
Material Path lengths Tolerance Specification
less than 10mm
± 0.02mm
Windows parallel to: better than 3 minutes of arc
10 to 30mm
± 0.1mm
Window flatness to: better than 4 Newton fringes
40 to 100mm
± 0.2mm
Window polish, standard: 60/40 scratch/dig
Special Optical Glass
up to 20mm
± 0.01mm
Window polish, laser: 20/10 scratch/dig
Special Optical Glass
30 to 100mm
± 0.02mm
0.01 to 0.05mm
± 0.002mm
0.1 to 0.4mm
± 0.005mm
0.5 to 100mm
± 0.01mm

Standard window thickness is 1.25mm, polished to better than 4 Newton Fringes per centimetre in the viewing area, typically flat to better than 1 micron (0.001mm) over the window area.
Although cells can be used with most solvents and acidic solutions, fluorinated acids such as Hydrofluoric Acid (HF) in all concentrations should be avoided as they will attack the quartz itself. Strong basic solutions (pH 9.0 and above) will also degrade the surface of the windows and 
shorten the useful life of the cells.
Flow cells with path lengths of less than 0.5mm are measured by an interference method both before and after final fusing.Calculation on this measurement provides an uncertainty of path length better than 0.2 microns (0.0002mm). Path length certification can be supplied for individual cells for a small additional charge.This must be requested at the time of ordering.

Window material transmission properties

material properties
Registered Trade Marks: INFRASIL® & Suprasil® 300 Heraeus Quarzglas GmbH, Hanau / Main, Germany SPECTROSIL®, Thermal Syndicate, England. PYREX® Corning Glass Works, U.S.A. 
The above information illustrates the approximate transmission ranges of the guaranteed materials used in the production of Starna cells. The traces are for a thickness of 5 mm, which is approximately double the total thickness of the windows that are used in the construction of most cells

Material specifications

Starna offer five primary window materials, Optical Glass (G) and Special Optical Glass (SOG) for the visible range. Spectrosil® Quartz (Q) or equivalent for the far UV range, Infrasil® Quartz (I) or equivalent for the near infra-red (IR) as well as Suprasil® 300 (SX) or equivalent which transmits from the far UV to the near infra-red. Other window materials are also available such as Pyrex (PX) and UV Silica (HH).
If a specific window material is required and is not shown in this catalogue please contact us for availability. All materials used are fully guaranteed to transmit greater than 80% over the following usable wavelength range:

Wave length range
Optical Glass G 334 through 2500 nm
Special Optical Glass SOG 320 through 2500 nm
Pyrex PX 325 through 2500 nm
UV Silica HH 230 through 2500 nm
Spectrosil® Quartz Q 190 through 2700 nm
Infrasil® I 220 through 3800 nm
Suprasil® 300 Quartz SX 190 through 3500 nm
For fluorescent applications Spectrosil® is the recommended window material, as it does not exhibit any background fluorescence. Some other materials, especially glass and lower grades of quartz may have some background fluorescence.
The meticulous care taken in the quality of the polishing and unique construction of regular Starna® quartz fluorescent cells brings them within tolerances which are sufficiently stringent for them to be used in laser applications. These techniques are particularly relevant in the manufacture of much larger Ultra High Vacuum (UHV) cells.