Pye Unicam

Infra-Red Spectrometry

Landmark Infra-Red Spectrometers

1950s - SP100

Designed by Frank Daly, the SP100 was a large, floor standing infrared vacuum spectrophotometer. It employed a prism/grating monochromator for high levels of resolution.

The optical system was mounted on top of the recording mechanism and vacuum pump, used for purging the optics. Prisms and two diffraction gratings ensured wavelength coverage from 1.1 micron to 26.7 micron.

The Golay detector worked by expansion of a gas filled enclosure when heated by infrared radiation. Light reflected off this membrane provided the measurement signal.

1960s - SP200

The SP200 was regarded as an “economy” infrared spectrophotometer, primarily for routine analysis in laboratories where simplicity was valued.

It was a double beam, null-balancing instrument with a more limited wavelength range than the more research orientated SP100.

A wavelength scan took a full ten minutes and the results presented on the in-built chart recorder.

A Nernst filament was used as the radiation source and detection was by means of a Golay cell.

1970s - SP1050,1100,1200

The SP100 and 200 were followed in the 1970s by smaller, lower cost benchtop systems, no longer vacuum instruments. The SP1000, followed by the SP1100 and SP1050, was developed by John Firth and team.

They had much simplified controls. Uniquely, the SP1100 had scale expansion of the transmittance scale to aid observation of spectral features.

In production in the early 1970s, they remained in the catalogue until 1979.

The SP1100 had a high resolution grating monochromator. The SP1200 produced higher sensitivity of measurement.

1979 - SP3

By the mid 1970s a new breed of instrument was under development – the SP3 Series.

Instead of the Golay cell detector, a pyroelectric detector (from Mullard) was used, allowing much faster response. The mechanical measuring system was replaced with an electronic ratio recording system. This compared the sample and reference beam intensities, producing superior spectra in much reduced time.

The SP3, launched in 1979, was available in a range of products. Shown is the SP3-300 with SP3-080 data control console.

1980s - SP2000, 4000

Around the late 1970s a lengthy programme led to the SP2000 and SP4000 infrared spectrophotometers developed by David Warner and his team.

These instruments were air purged from an air dryer to remove atmospheric absorption. They were high cost/higher performance systems with considerable automation and data processing.

Like the SP3, they employed the use of plastic mouldings for the instrument covers and some internal components.

1980s - PU9510

The world of IR spectrophotometry was changing rapidly in the 1980s. The Fourier Transform Infra-Red spectrophotometry technique was being introduced by competitors and Pye Unicam had to respond.

In this technique the spectrum is obtained by scanning an interferometer and then performing a Fourier Transform on the recorded scan (an interferogram). This provides great improvement in the noise levels and speed of analysis.

The PU9510 was Unicam’s first use of this technology, offering high speed and much improved signal characteristics.

1992 - Mattson Unicam FTIR Series

Following the acquisition of the business by ATI in 1991, early Unicam developments of FTIR spectrophotometers were replaced by the Mattson Unicam FTIR Series 1000, 3000, 5000 and 7000 instruments.

These provided an ever increasingly comprehensive set of features and facilities, from basic QC and Teaching laboratories right through to Research grade products.

They were also available with FIRST data station software for advanced sample identification and data processing.