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. 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 |
Optiglass
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: |
Optical
Glass
Special Optical Glass
Pyrex
UV Silica
Spectrosil® Quartz
Infrasil®
Suprasil® 300 Quartz |
G
SOG
PX
HH
Q
I
SX |
334
through 2500 nm
320 through 2500 nm
325 through 2500 nm
230 through 2500 nm
190 through 2700 nm
220 through 3800 nm
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. |