EP0055027A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Apparatus for deriving an electrical signal from a radiation flash and instruments incorporating such apparatus
Assignee: Wilj International Ltd
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Filing: 1981-11-19
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Granted: —
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Expires: 2001-11-19
Abstract
Abstract Apparatus for deriving from at least one flash of radiation a signal representative of the quantity of radiation contained in the flash or flashes, the apparatus comprising a radiation detector (32) for receiving said flash of radiation and providing an electrical detector output signal (A) which includes a pulse generated in response to said flash, and processing means (36 to 62) arranged to receive said detector output signal and to provide said representative signal, the processing means being operative to substantially remove, in the representative signal, the effect of any D.C. component on which the pulse or pulses may have been superimposed in the detector output signal. In one embodiment (Fig. 3), the processing means operates by filtering the detector output signal and passing only its A.C. components. In another embodiment, the signal level in the absence of flashes is measured, the signal level in the presence of flashes is measured, and the measurements are subtracted.
Inventors
- 👤 Dennis William Nixon
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 12:41
CPC Classifications
G; G01; G01J; G01J1/00; G01J1/42; G01J1/44
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
110 words
Apparatus for deriving from at least one flash of radiation a signal representative of the quantity of radiation contained in the flash or flashes, the apparatus comprising a radiation detector (32) for receiving said flash of radiation and providing an electrical detector output signal (A) which includes a pulse generated in response to said flash, and processing means (38 to 62) arranged to receive said detector output signal and to provide said representative signal, characterised in that the processing means is operative to substantially remove, in the representative signal, the effect of any D.C. component on which the pulse or pulses may have been superimposed in the detector output signal.
Claim 2
Dependent Claim
110 words
Apparatus for deriving from at least one flash of radiation a signal representative of the quantity of radiation contained in the flash or flashes, the apparatus comprising a radiation detector (32) for receiving said flash of radiation and providing an electrical detector output signal (A) which includes a pulse generated in response to said flash, and processing means (38 to 62) arranged to receive said detector output signal and to provide said representative signal, characterised in that the processing means is operative to substantially remove, in the representative signal, the effect of any D.C. component on which the pulse or pulses may have been superimposed in the detector output signal.
Claim 3
Dependent Claim
81 words
Apparatus as claimed in claim 1, characterised in that the processing means includes filtering means (38) for receiving said detector output signal at an input thereof and passing to an output thereof only A.C. components of said signal, whereby a filter output pulse occurs in response to a detector output signal pulse, and means (40, 42) for holding the output of said filtering means substantially at a predetermined reference level in the absence of an output pulse from the filtering means.
Claim 4
Dependent Claim
29 words
Apparatus as claimed in claim 2, characterised in that said processing means includes means (60,62) for integrating the signal at said filtering means output, or a signal derived therefrom.
Claim 5
Dependent Claim
28 words
Apparatus as claimed in claim 2 or claim 3, characterised in that said holding means comprises unidirectionally conductive means (40) coupled to the output of the filtering means.
Claim 6
Dependent Claim
27 words
Apparatus as claimed in claim 4, characterised in that said holding means further comprises biassing means (42) for maintaining said unidirectionally conductive means in a conductive state.
Claim 7
Dependent Claim
18 words
Apparatus as claimed in claim 4 or 5, characterised in that said biassing means is a current source.
Claim 8
Dependent Claim
45 words
Apparatus as claimed in claim 5 or claim 6, characterised in that said holding means further comprises a sensing circuit (44) arranged to sense the presence of an output pulse at said filtering means output and in response to suppress operation of said biassing means.
Claim 9
Dependent Claim
38 words
Apparatus as claimed in claim 7, characterised in that said sensing circuit (44) is a comparator arranged to compare the output voltage of said filtering means with said predetermined level to sense the presence of said output pulse.
Claim 10
Dependent Claim
32 words
Apparatus as claimed in any one of claims 2 to 8, characterised in that the filtering means comprises at least one capacitor (38) in series connection between its input and its output.
Claim 11
Dependent Claim
65 words
Apparatus as claimed in claim 1, characterised in that said processing means is operable (2) to subtract, from the detector output signal value occurring when one or more flashes are received, or from a signal value derived therefrom, the detector output signal value occurring when no flashes are received, or a signal value derived therefrom, to substantially remove the effect of any said D.C. component.
Claim 12
Dependent Claim
57 words
Apparatus as claimed in claim 10, characterised in that said processing means is operable to integrate the detector output signal, or a signal derived therefrom, throughout a time period (20) during which a succession of flashes are received, and throughout a time period (22) when flashes are not received, and to subtract one integral from the other.
Claim 13
Dependent Claim
26 words
Apparatus as claimed in claim 10 or claim 11, characterised in that the detector output is applied to the processing means through a D.C. amplifier (36).
Claim 14
Dependent Claim
27 words
Apparatus as claimed in claim 10, characterised in that the detector output signal value is repeatedly sampled, during and between flashes, and individual sample values are subtracted.
Claim 15
Dependent Claim
42 words
Apparatus as claimed in claim 10, characterised in that the detector output signal value is repeatedly sampled, during and between flashes, the sample values taken during flashes and the sample values taken between flashes are integrated separately, and the integrals are subtracted.
Claim 16
Dependent Claim
58 words
Apparatus as-claimed in any one of claims 2 to 9, characterised in that said processing means is operable to subtract, from the filtering means output signal value occurring when one or more fLashes are received, or from a signal derived therefrom, the filtering means output signal value occurring when no flashes are received or a signal derived therefrom.
Claim 17
Dependent Claim
58 words
Apparatus as claimed in claim 15, characterised in that said processing means is operable to integrate the filtering means output signal, or a signal derived therefrom, throughout a time period (20) during which a succession of flashes are received, and throughout a time period (22) when flashes are not received, and to subtract one integral from the other.
Claim 18
Dependent Claim
28 words
Apparatus as claimed in claim 15, characterised in that the filtering means output signal value is repeatedly sampled, during and between flashes, and individual sample values are subtracted.
Claim 19
Dependent Claim
43 words
Apparatus as claimed in claim 15, characterised in that the filtering means output signal value is repeatedly sampled, during and between flashes, the sample values taken during flashes and the sample values taken between flashes are integrated separately, and the integrals are subtracted.
Claim 20
Dependent Claim
58 words
Apparatus as claimed in claim 11 or claim 16, characterised in that said processing means comprises a single integrator for deriving both integrals, and two storage means, one of the integrals derived by the integrator is stored in one of the storage means and the other of the integrals is stored in the other of the storage means.
Claim 21
Dependent Claim
32 words
Apparatus as claimed in claim 11, 12, 16 or 19, characterised in that it comprises means (46 to 56) for lengthening pulses in the signal to be integrated, prior to their integration.
Claim 22
Dependent Claim
47 words
Apparatus as claimed in claim 20, characterised in that the lengthening means comprises a capacitive circuit (56) which is charged in proportion to the amplitude of the pulse it receives, and which has a discharge time constant which is substantially longer than the duration of said pulse.
Claim 23
Dependent Claim
104 words
An instrument comprising a radiation source (6), means (2) for causing the source to emit flashes of radiation, reference (10) and measurement (8) optical paths leading to.respective reference (12) and measurement (12') channels and characterised in that the reference channel (12) comprises a first apparatus as claimed in any preceding claim having its radiation detector arranged to receive said flashes of radiation from the reference optical path, and the measurement channel (12') comprises a second such apparatus having its radiation detector arranged to receive said flashes of radiation, or flashes of radiation derived therefrom by a sample under measurement, from the measurement optical path.
Claim 24
Dependent Claim
54 words
An instrument as claimed in claim 22, characterised in that said apparatus are in accordance with any one of claims 11, 14, 16, 18 or 19, and comprising means for deriving the ratio of the difference between the two integrals from one channel and the difference between the two integrals from the other channel.
References Cited (Backward Citations)
No citation records indexed.
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