Particulate detector

A particulate detector comprising:

• a radiation source arranged to emit radiation in at least first and second predetermined wavebands towards a sampling region;
• and
• a detection element arranged to detect radiation from the sampling region at least first and second instances;
• wherein the radiation source is such that the emissions in the at least first and second predetermined wavebands temporarily overlap;
• wherein the detector is such that, at the instances at which the radiation is detected, the relative contributions from the emissions in each predetermined waveband are distinguishable, thereby allowing characteristics of particulates in the sampling region to be determined;
• and
• wherein the radiation source further comprises a phosphor layer arranged to absorb a proportion of the radiation in the first predetermined waveband, and to emit radiation in the second predetermined waveband.

A particulate detector comprising:

• a radiation source arranged to emit radiation in at least first and second predetermined wavebands towards a sampling region;
• and
• a detection element arranged to detect radiation from the sampling region at least first and second instances;
• wherein the radiation source is such that the emissions in the at least first and second predetermined wavebands temporarily overlap;
• wherein the detector is such that, at the instances at which the radiation is detected, the relative contributions from the emissions in each predetermined waveband are distinguishable, thereby allowing characteristics of particulates in the sampling region to be determined;
• wherein the radiation source further comprises a second light emitting diode for emitting radiation in the second predetermined waveband;
• and
• wherein the radiation source is arranged such that radiation emitted in the first redetermined waveband is used to power the second light emitting diode.

A detector system comprising a control unit and a plurality of particulate detectors, each particulate detector comprising:

• a radiation source arranged to emit radiation in at least first and second predetermined wavebands towards a sampling region;
• and
• a detection element arranged to detect radiation from the sampling region at least first and second instances;
• wherein the radiation source is such that the emissions in the at least first and second predetermined wavebands temporarily overlap;
• wherein the detector is such that, at the instances at which the radiation is detected, the relative contributions from the emissions in each predetermined waveband are distinguishable, thereby allowing characteristics of particulates in the sampling region to be determined;
• and
• wherein the radiation source further comprises a phosphor layer arranged to absorb a proportion of the radiation in the first predetermined waveband, and to emit radiation in the second predetermined waveband.