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News: ISS distribute Hellma Analytics Cells and Optical Components

Article Date(s):02/03/2012 - 02/03/2012

Hellma Analytics Cells are manufactured from various types of glass. The most important criterion for the choice of a particular type of glass is the spectral range for which the cell is intended. Coloured logos are fused onto each Hellma cell, thus indicating the spectral range over which the cell can be used.

In general we divide the glass materials that we use into two groups: quartz and optical glass. Quartz consists exclusively of silicon dioxide (SiO2) and shows some remarkable properties:

  • Quartz displays a high UV transmission, in highly purified synthetic quartz down to well below 200 nm.
  • The thermal expansion of quartz is extremely low, its coefficient of thermal expansion being 6 x 10-7K-1 between 20 °C and 300 °C. 
  • Quartz is chemically very resistant and maintains its shape, even at high temperatures up to approximately 1000 °C. 

Common criteria for all types of optical glass are:

  • that the cells made from it are used in the visible range of the spectrum
  • that the glasses we use are characterised by relatively low values of refractive indexand dispersion
  • that they display good resistance to chemicals.

Material Code


Identification Logos for UV Cells
Identification Logos for NIR Cells
Identification Logos for Cells for the Visible Spectrum

transmission curveTransmission of empty cells made of different materials


UV/Vis calibration standards from the accredited Hellma Analytics calibration laboratory

Hellma Analytics calibration standards for UV/Vis spectroscopy meet internationally recognised standards and provide for highest process transparency. They ensure dependable examinations of the spectral resolution , the wavelength accuracy as well as the checking for stray light and photometric accuracy.

 

Your advantages at a glance:

  • Saves valuable time
  • Increases the quality of your work
  • Ensures regulation conformity

The set of liquid Hellma calibration standards enables the checking of spectrophotometers with respect to

667.009-UV

The set of solid Hellma calibration standards enables the checking of spectrophotometers with respect to

image_666.000_frei_F1.jpg


Solid filter set











Material and Technical Information

QS

QS is the identification logo which indicates that Quartz of the highest purity and homogeneity has been used for the window. Because it is produced from a silicon compound, it is also called synthetic Quartz. We use Quartz SUPRASIL from Heraeus Quarzglas GmbH, with which gives transmission values of more than 80 % over a spectral range of between 200 nm and 2500 nm for an empty cell.

UV

QH or UV are the trademarks which identity a Quartz that has been manufactured by melting natural crystalline quartz. We use HERASIL Quartz from Heraeus Quarzglas GmbH or equivalent material from other suppliers. An empty cell manufactured from this material gives a transmission of more than 80 % over a spectral range of between 260 nm and 2500 nm.

QX

QX stands for a synthetic Quartz that is free from OH absorption. Therefore it is suitable for applications in the near infrared range up to approximately 4000 nm. We use Quartz SUPRASIL 300 from Heraeus Quarzglas GmbH, which gives a transmission of more than 80 % over a spectral range of between 200 nm and 3500 nm for an empty cell.

OS

OS indicates that SCHOTT type UK 5 is used for cells referred to in the catalogue as manufactured from “Special Optical Glass”. This crown glass is made from exceptionally pure raw materials, which gives an improved transmission in the near ultraviolet range. An empty cell will give a transmission of more than 80 % over a spectral range of between 320 nm and 2500 nm.

OG

OG is a trademark that distinguishes cells which are not used in spectrophotometry. Here, a glass is used, which we refer to in the catalogue as “Optical Glass”. We use B 270-Superwite from SCHOTT DESAG, a colourless highly transparent crown glass in the form of drawn panes with fire-polished surfaces. The quality of the surfaces is so high that the components can be fused using the Hellma process without further grinding and polishing. An empty cell made of B 270-Superwite will give a transmission of more than 80 % over a spectral range of between 360 nm and 2500 nm.

Materialcode_BF

BF is the trademark for cells which are manufactured entirely from borosilicate glass, the composition and properties of which are laid down by an international standard. This type of glass possesses a high chemical resistance and a low coefficient of thermal expansion of 3.3 x 10-6 K-1. This makes it particularly suitable for use as laboratory glassware. For the windows of these cells we use SCHOTT Borofloat, a borosilicate glass manufactured using the float process. It combines the good chemical properties of Duran with very good optical properties (homogeneity, transmission). An empty cell made from this material has a transmission of greater than 80 % at a spectral range of between 330 nm and 2500 nm.

transmission curveTransmission of empty cells made of different materials

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