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- From Robb Habbersett:
Hamamatsu makes several tubes with extended red response and they
are side window tubes just like the R928 so they should fit in the
BD PMT sockets. The tubes are R1477 and a new one R3896. Actually
the R928 is listed as an extended red responding tube (beyond 800nm)
but the 1477 and 3896 are better still. You can specifically request
high sensitivity tubes (essentially hand selected) at the expense
of slightly higher dark current. Generally flow instruments have
high ambient light levels such that dark current is not a problem.
Hamamatsu - 201/469-6640
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- From Dennis Sasaki:
Hamamatsu makes a red sensitive R3896 PMT which you may find
interesting. We have used the #928 and the now unavailable #1477 (BDIS).
R3896: High OE multialkai photocathode.
1 1/8" diameter
9 stage
Side-on
185-900 nm spectral response.
525 mcA/lm
Hamamatsu Corporation
360 Foothill Road
PO Box 6910
Bridgewater, NJ 08807-0910
800-524-0504
908-231-1539 (fax)
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- From Robert C. Leif
The best red sensitive PMTs are Gallium Arsenide, which are very expensive.
Try Hammamatsu 1-800-524-0504, 908-231-0960 for regular red sensitive tubes.
Another approach is to use an avalanche photodiode. There are two sources:
EG&G Optoelectronics, 22001 Dumberry RD. box 900, Vaudreuil, Quebec PQJ7V
7X3 514-424-3300.
Attn. Andrew Mcgreger Ph.D. These are low voltage small area.
Advanced Photonics 805-987-0146 1240 Avenida Acaso, Camarillo, Ventura CA.
These are high voltage large area.
The use of Avalanche diodes has been reported in Cytometry. But for some
reason they were run at 37 C. As with any diode,
the cooler you go the lower the noise. Beware with avalanches, their gain
increases as the temperature decreases. You can destroy them by cooling.
-- ============================================================================== Thomas Delohery | Internet: t-delohery@ski.mskcc.org Manager, Flow Cytometry Core Facility | Phone: (212) 639-8729 Memorial Sloan-Kettering Cancer Center | Fax: (212) 794-4019 ==============================================================================
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