Cell 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 3 x 105 Pa (three atmospheres). (see MSDS)

General specifications

Windows parallel to:
Window flatness to:
Window polish, standard:
Window polish, laser:

better than 3 minutes of arc
better than 4 Newton fringes
60/40 scratch/dig
20/10 scratch/dig

Material

Path lengths

Tolerance

Glass
Glass
Glass
Special Optical Glass
Special Optical Glass
Quartz
Quartz
Quartz

less than 10mm
10 to 30mm
40 to 100mm
up to 20mm
30 to 100mm
0.01 to 0.05mm
0.1 to 0.4mm
0.5 to 100mm

± 0.02mm
± 0.1mm
± 0.2mm
± 0.01mm
± 0.02mm
± 0.002mm
± 0.005mm
± 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

Registered Trade Marks: INFRASIL® & Suprasil® 300 Heraeus Quarzglas GmbH, Hanau / Main, Germany.
SPECTROSIL®, Thermal Syndicate, England. Borofloat® 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 Scientific offer the following window materials: Optical Glass (G), Special Optical Glass (SOG), & Borofloat® (PX) for the Visible range; UV Silica Quartz(HH) for UV; Spectrosil® Quartz (Q) or equivalentfor FarUV & Visible, Infrasil® Quartz (I) or equivalent for UV through Near Infra-red (IR); Suprasil 300® Quartz (SX) or equivalent for FarUV through Near IR..
If a specific window material is required and is not shown in this catalogue please contact us for availability.

The following table shows the Usable Range (UR) and the range over which the transmission is guaranteed better than 80%.

Material	Abreviation	UR From	>80% from nm
Optical Glass	G	334 nm	360 through 2500 nm
Special Optical Glass	SOG	320 nm	320 through 2500 nm
Borofloat	PX	325 nm	330 through 2500 nm
UV Silica	HH	220 nm	260 through 2500 nm
Spectrosil® Quartz	Q	190 nm	200 through 2500 nm
Infrasil®	I	220 nm	220 through 3800 nm
Suprasil® 300 Quartz	SX	190 nm	200 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.

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