GB1583262A

GB1583262A - Device for photo-electric recording of spectra

Info

Publication number: GB1583262A
Application number: GB190477A
Authority: GB
Original assignee: Carl Zeiss Jena GmbH
Current assignee: Jenoptik AG
Priority date: 1976-01-19
Filing date: 1977-01-18
Publication date: 1981-01-21
Also published as: FR2338484A1; DD124329A1; DE2648591A1; FR2338484B1

Description

(54) DEVICE FOR PHOTO-ELECTRIC RECORDING OF SPECTRA (71) We, VEB CARL ZEISS JENA, a Corporation organised under the laws of the German Democratic Republic, of Carl-Zeiss Strasse, Jena, German Democratic Republic, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a device for photo-electric recording of spectra produced by a radiation source to be investigated, comprising an optical collimating system for directing the radiation to an optical dispersion system arranged in a pressure chamber, followed by an optical imaging system and a photo-electric detector.

In previous devices for photo-electric recording of a spectrum the latter is scanned by means of a slit and recorded by a photoelectric detector. Such a scanning of the spectrum is either obtained by rotating the optical dispersion means or by displacement of the slit detector unit. For highly resolving spectrum records, the adjustment of the optical dispersion means or of the displacement of the slit/detector/unit requires high precision which in turn can only be obtained by a considerable mechanical expenditure, the latter involving an increase in the mass of the device which limits its mobility.

It is an object of the present invention to obviate the above disadvantages.

It is a further object of the present invention to provide a device for photo-electric recording of a spectrum which eliminates the high mechanical expenditures for the displacement and adjustment means and which eliminates interferences of the measurements due to movements of the device.

To this end, the present invention consists in a device for the photo-electric recording of a spectrum produced by a radiation source, to be investigated, comprising an optical collimating system, a windowed pressure chamber, an optical dispersion means in said chamber, an optical imaging system, and a photo-electric detector, said optical collimating system being arranged to direct radiation from said source through a window to said optical dispersion means to produce a spectrum which then leaves the chamber via the same or another window, and said optical imaging system serving for imaging the spectrum at the photo-electric detector, means being provided to change the pressure within the pressure chamber whereby to change the refractive index of the medium within the chamber to effect scanning of the spectrum across the detector.

The invention provides, within a pressure chamber, an optical dispersion means which spectrally decomposes a radiation. The scanning of the spectrum is effected by refractive index changes caused by pressure variations to which the medium in the pressure chamber is subjected. The scanning range depends on the relative positions of the dispersion means, the entrance window, and the exit window, and the refractive index of the medium in the pressure chamber. With a predetermined dispersion of the optical dispersion means not only the scanning range but also the direction, that is, a scanning towards lower or higher wavelengths can be effected by a suitable selection of the position of the entrance and exit windows of the pressure chamber.

It is to be understood that in the course of a measuring operation, the entrance and the exit windows as well as the optical dispersion means remain unchanged. The scanning direction, however, can be adjusted by variation of the pressure either to higher or to lower pressure values.

In order that the invention may be more readily understood reference is made to the accompanying drawings which illustrate-diagrammatically and by way of example three embodiments thereof, and in which : Fig. 1 shows a schematical representation of one embodiment of the device for recording spectra, Fig. 2 shows the pressure chamber of Fig. 1, Fig. 3 shows an alternative arrangement of the pressure chamber and windows, and Fig. 4 shows a further alternative arrangement of the pressure chamber and windows.

In Fig. 1 radiation emitted from a light source 1 impinges on a grating 3 via an optical collimating system 2 and through a window 8 of a pressure chamber 4. The radiation from the grating 3 impinges upon a photo-electric detector 6 after passage through a second window 7 of the pressure chamber 4 and via an optical imaging system 5. The pressure chamber 4 is connected via a connection duct 9 to a pressure varying device 13.

A bundle of light 10 from the light source 1 impinges upon the optical collimating system 2 which directs the bundle of light 10 as parallel light through the window 8 to the grating 3 in the pressure chamber 4. The grating 3 (dispersion means) effects a spectral splitting up of the bundle of parallel light 10. A bundle of parallel light 15, originating from the grating 3 impinges upon the optical imaging system 5 after passage through the window 7, from whence it is focussed on to the photo-electric detector 6.

The detector 6 converts the intensity variations of the spectrally split up radiation into corresponding electric signals, which are fed into a recording means (not shown).

The scanning of the spectral radiation by means of a refractive index change caused by a pressure variation is carried out by the pressure varying device 13 which is connected to the pressure chamber 4 via the duct 9.

Fig. 2 shows the pressure chamber 4 of Fig. 1 with windows 7, 8. Radiation 14 impinges upon the grating 3 through the window 8 and a spectrally split up radiation leaves the pressure chamber 4 by the window 7. In the arrangement of the windows 7, 8 as shown in Fig. 1, a spectrum is scanned over a range of 4.6 A per atmosphere change of pressure, either towards shorter wavelengths or longer wavelengths, which depends on whether a pressure increase or a pressure decrease takes place.

The refractive index at normal pressure of the medium in the pressure chamber is 1.

In the window arrangement shown in Fig.

3, the radiation 14 enters the pressure chamber 4 by a window 11 and, after spectral splitting up, leaves the chamber 4 by the same window 11. The scanning range in this arrangement is 8.2 A per atmosphere change of pressure, under the same conditions as described in connection with Fig. 1.

When an arrangement as shown in Fig.

4 is employed in which the radiation 14 enters the pressure chamber 4 by a window 16 and, after spectral decomposition, leaves the same by a window 17, a range of 1.9 A per atmosphere change of pressure is scanned.

WHAT WE CLAIM IS:- 1. A device for the photo-electric recording of a spectrum produced by a radiation source, to be investigated, comprising an optical collimating system, a windowed pressure chamber, an optical dispersion means in said chamber, an optical imaging system, and a photo-electric detector, said optical collimating system being arranged to direct radiation from said source through a window to said optical dispersion means to produce a spectrum which then leaves the chamber via the same or another window, and said optical imaging system serving for imaging the spectrum at the photo-electric detector, means being provided to change the pressure within the pressure chamber whereby to change the refractive index of the medium within the chamber to effect scanning of the spectrum across the detector.

2. A device as claimed in claim 1, having two windows in the pressure chamber, wherein one window is at right angles to the optical dispersion means and the other is at an acute angle thereto.

3. A device as claimed in claim 1, having two windows in the pressure chamber, wherein one window is parallel to the optical dispersion means and the other window is at an acute angle thereto.

4. A device as claimed in claim 1, having one window in the pressure chamber, wherein said window is at an acute angle to the optical dispersion means.

5. A device for the photo-electric recording of a spectrum, substantially as hereinbefore described with reference to and as shown in Figs. 1 and 2, or Fig. 3 or Fig.

4 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

In Fig. 1 radiation emitted from a light source 1 impinges on a grating 3 via an optical collimating system 2 and through a window 8 of a pressure chamber 4. The radiation from the grating 3 impinges upon a photo-electric detector 6 after passage through a second window 7 of the pressure chamber 4 and via an optical imaging system 5. The pressure chamber 4 is connected via a connection duct 9 to a pressure varying device 13.

A bundle of light 10 from the light source 1 impinges upon the optical collimating system 2 which directs the bundle of light 10 as parallel light through the window 8 to the grating 3 in the pressure chamber 4. The grating 3 (dispersion means) effects a spectral splitting up of the bundle of parallel light 10. A bundle of parallel light 15, originating from the grating 3 impinges upon the optical imaging system 5 after passage through the window 7, from whence it is focussed on to the photo-electric detector 6.

The detector 6 converts the intensity variations of the spectrally split up radiation into corresponding electric signals, which are fed into a recording means (not shown).

The scanning of the spectral radiation by means of a refractive index change caused by a pressure variation is carried out by the pressure varying device 13 which is connected to the pressure chamber 4 via the duct 9.

Fig. 2 shows the pressure chamber 4 of Fig. 1 with windows 7, 8. Radiation 14 impinges upon the grating 3 through the window 8 and a spectrally split up radiation leaves the pressure chamber 4 by the window 7. In the arrangement of the windows 7, 8 as shown in Fig. 1, a spectrum is scanned over a range of 4.6 A per atmosphere change of pressure, either towards shorter wavelengths or longer wavelengths, which depends on whether a pressure increase or a pressure decrease takes place.

The refractive index at normal pressure of the medium in the pressure chamber is 1.

In the window arrangement shown in Fig.

3, the radiation 14 enters the pressure chamber 4 by a window 11 and, after spectral splitting up, leaves the chamber 4 by the same window 11. The scanning range in this arrangement is 8.2 A per atmosphere change of pressure, under the same conditions as described in connection with Fig. 1.

When an arrangement as shown in Fig.

4 is employed in which the radiation 14 enters the pressure chamber 4 by a window 16 and, after spectral decomposition, leaves the same by a window 17, a range of 1.9 A per atmosphere change of pressure is scanned.

WHAT WE CLAIM IS:- 1. A device for the photo-electric recording of a spectrum produced by a radiation source, to be investigated, comprising an optical collimating system, a windowed pressure chamber, an optical dispersion means in said chamber, an optical imaging system, and a photo-electric detector, said optical collimating system being arranged to direct radiation from said source through a window to said optical dispersion means to produce a spectrum which then leaves the chamber via the same or another window, and said optical imaging system serving for imaging the spectrum at the photo-electric detector, means being provided to change the pressure within the pressure chamber whereby to change the refractive index of the medium within the chamber to effect scanning of the spectrum across the detector.
2. A device as claimed in claim 1, having two windows in the pressure chamber, wherein one window is at right angles to the optical dispersion means and the other is at an acute angle thereto.
3. A device as claimed in claim 1, having two windows in the pressure chamber, wherein one window is parallel to the optical dispersion means and the other window is at an acute angle thereto.
4. A device as claimed in claim 1, having one window in the pressure chamber, wherein said window is at an acute angle to the optical dispersion means.
5. A device for the photo-electric recording of a spectrum, substantially as hereinbefore described with reference to and as shown in Figs. 1 and 2, or Fig. 3 or Fig.

4 of the accompanying drawings.