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Article #5186Re: Need help ... is there any inexpensive device that
From: John Whitmore
Date: Sat, 21 Jul 1990 04:37
Date: Sat, 21 Jul 1990 04:37
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In article <1990Jul21.023806.12927@hayes.fai.alaska.edu> ftpam1@acad3.fai.alaska.edu writes: >In article <14380@venera.isi.edu>, sllu@jenny.isi.edu (Shih-Lien Lu) writes... >>will detect UV light only (200nm to 400 nm wave length)? >>If not, is there any device that will detect light down to 200 nm wave >>length? > > Photomultiplier tubes (possibly with optic filtering). Or perhaps simple photocells. The bias voltage on a photomultiplier (PMT) tube's first cathode can be deliberately degraded (run low) so that only energetic photons (UV) generate electrons... this is the 'photoelectric effect' that Einstein got his Nobel for explaining. Photocells, while having MUCH lower currents, are easier to bias. Look up 'stopping potential' in any discussion of photoelectricity. John Whitmore
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!rutgers!usc!samsung!emory!ogicse!milton!whit From: whit@milton.u.washington.edu (John Whitmore) Newsgroups: sci.electronics Subject: Re: Need help ... is there any inexpensive device that Summary: Bias of phototube or photomultiplier can change spectrum Message-ID: <5350@milton.u.washington.edu> Date: 21 Jul 90 04:37:24 GMT References: <14380@venera.isi.edu> <1990Jul21.023806.12927@hayes.fai.alaska.edu> Organization: University of Washington, Seattle Lines: 17