RedShift designs and manufactures a wide range of Long Path Cells (from 2.4 meter to 32 meter) for IR and FTIR instruments with Variable or Fixed Pathlength, in order to measure from percent to ppb levels of gas mixtures concentration and trace their components.

These IR accessories give high performances, they are durable, reliable and easy to maintain. Long Path Cells are suitable for:

  • air pollution analysis,
  • research and academic studies of unknown gaseous mixtures,
  • gas purity determinations,
  • to monitor industrial processes,
  • exhaust gas analysis,
  • and more…

RedShift Design

RedShift long path cells have a compact design with sturdy black anodized aluminum hardwares, cell body is cylindrinc and made in borosilicate glass or in stainless steel: body material depends strictly on the type of samples analyzed (see also our stainless steel long path cell for reactive and corrosive gases).

Internal mirrors can be gold plated and nickel coated for high reflectivity for standard analysis, or in stainless steel for applications with reactive and corrosive gases, they are resistant, with an optical substrate stronger and durable from the ones made in aluminum.

The overall path, either for fixed or variable pathlength, is achieved by repeated reflections within the gas cell: longer cells are suitable to measure lower gas concentration; in case of low quantities of gas samples to analyze, or high temporal resolution, a smaller cell volume is needed to guarantee an efficient gas exchange and a repeatible analysis.

Gas cells may be configured also for heating, this feature is implemented to prevent condensation of high boiling gases. These models are provided with an heating jacket protected by a metal housing which allows the operator moving and positioning it easily. The heated device is equipped with a main controller to program and check temperature and monitoring optional features.

RedShift long path cells are configured as shown in the figures below, but we can produce custom configurations based on your request, choosing:

  • cell body and path,
  • mirrors,
  • windows,
  • heating.

Variable or fixed pathlength?

Long Path Cell, known also as White Cell, is a device containing mirrors for reflecting the FTIR beam and, as model requested, it can be protected in a metal box which contains heaters. The cell path can be permanently aligned to a precise pathlength or it can be variable and freely adjustableBoth cells stands vertically inside the FTIR sample compartment.

Cells with adjustable optical path are equipped with two plane transfer mirrors couple on the bottom which allow the infrared beam in and out of the cell for a number of passes. Cell with fixed path have a permanent optical path established at the time of order and cannot be changed hereafter.