Path: 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

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