Detection & Imaging Tubes

This exhibit includes a range of detection devices, primarily photomultipliers, phototubes and camera tubes. Photomultiplier (PMTs) and phototubes are light-detecting tubes used in electric eyes, video cameras and various astronomical applications. Phototubes are simple devices, often gas-filled, consisting of a photocathode and anode. PMTs are more complex high-vacuum devices.

PMTs are extremely sensitive, some capable of detecting single photons. They amplify their photocathode's extremely small signal by passing the discharge through a chain of specialized electrodes called dynodes, which are each held at a successively higher voltage potential. In 9-stage PMTs, the voltage difference between photocathode and anode are typically in the range of 1000V, though they can be operated at lower voltages with a corresponding decrease in signal amplification. The sensitivity of a PMT is expressed in the form of quantum efficiency, a percentage describing the ratio between the number of incoming photons versus the number of electrons produced by the photocathode. Some PMTs have a signal gain in the tens of millions.

Amperex PM-2412B
 Amperex PM-2412B

The Amperex PM-2412B is a top-sensing 10-stage linear cascade photomultiplier with a venetian blind aperture and a 3" window. The PM-2412B is intended for use in gamma cameras and other scintigraphy applications.

Photonis XP2412B Datasheet

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Cetron CE-1C
 Cetron CE-1C

The CE-1C is Cetron's equivalent of the RCA 918, an early gas-filled phototube with a semicylindrical photocathode surrounding a central anode. The electrical characteristics of the 918 are extremely similar to those of the more common RCA 930 / 1P40 phototube, but the elongated envelope of the 918 accommodates a photocathode which is nearly double the size of the 930 photocathode. The 918 and CE-1C have a S-1 spectral response and a peak sensitivity of 800nm.

RCA 918 Datasheet (PDF)

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EMI 'Tabby' CV144
 EMI 'Tabby' CV144

The CV144 is an infrared image converter developed for military night vision applications during World War II. Surplus tubes later made it to the commercial market and were utilized in infrared monoculars and other similar devices.

The CV144 is part of a series of tubes (CV142-CV149) which were all manufactured as the same part, individually graded during inspection for their maximum operational voltage, then assigned a part number accordingly. CV144 is the most typical grade.

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Fairchild DuMont 6467
 Fairchild DuMont 6467

The DuMont 6467 is a 10-stage photomultiplier with an apical window. Instead of employing RCA's ubiquitous 9-stage circular configuration, the 6467 has a linear cascade of silver-magnesium dynodes, which provide a high signal-to-noise ratio at low light levels. The 6467 has a S-4 spectral response, with sensitivity peaking between 350 and 450nm.

The 6467 pictured here is a later example, manufactured after DuMont Laboratories was acquired by Fairchild Camera & Instrument in 1960.

Du Mont 6467 Datasheet (PDF)

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General Electric GL-1P39
 General Electric GL-1P39

Originally developed by RCA, the 929 / 1P39 is an early vacuum phototube with a semicylindrical photocathode surrounding a central anode. The 929 has a S-4 spectral response and a peak sensitivity of 420nm. The example pictured here is a second-source GL-1P39, manufactured by General Electric.

The RCA JAN-CRC-1P39 was the light sensing element used in the AN/ASH-4 Light & Time Recording Set, a device used to determine the yield of a nuclear explosion.

RCA 929 Datasheet (PDF)

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Hamamatsu R444
 Hamamatsu R444

The Hamamatsu R444 is the ultimate evolution of RCA's original nine-stage design, with a conventional circular cage of dynodes scaled down to sub-miniature size. The R444 is a high sensitivity UV detector, with a 340nm peak response.

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Hamamatsu R488
 Hamamatsu R488

The Hamamatsu R488 is a small end-view phototube optimized to detect UV light. While most phototubes are gas-filled, the R488 is a vacuum device.

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Hamamatsu R928
 Hamamatsu R928

The Hamamatsu R928 is classic 9-stage circular cage PMT with a wide spectral response. The R928 features a 185-900nm sensitivity range, a proprietary multialkali photocathode and 25.4% peak quantum efficiency.

Hamamatsu R928 Datasheet

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Hitachi HS250
 Hitachi HS250

The Hitachi HS250 is a Vidicon tube of unknown specification. If you can provide any information about this device, please contact us.

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Honeywell 113228
 Honeywell 113228

The Honeywell 113228 is a gas-filled phototube designed to detect UV light. While most photubes are filled with argon, the 113228 is filled with neon. The 113228 was designed for use in Honeywell's Purple Peeper and Mini Peeper industrial flame sensors.

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Matsushita S4097A
 Matsushita S4097A

The Matsushita S4097A is compact, lightweight Vidicon camera tube, intended for use in handheld television cameras and surveillance cameras.

Matsushita Vidicon Tubes (PDF)

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RCA 921
 RCA 921

Devices included in this entry:

General Electric 921 gas-filled phototube (pictured in thumbnail)
RCA JRC-921 gas-filled phototube (pictured in thumbnail)


Introduced in 1939, the RCA 921 is an early cartridge type gas-filled phototube, similar in performance to the 930, with an S-1 spectral response and 800nm peak sensitivity. The 921 was once popular in light-operated relay applications.

RCA 921 Datasheet (PDF)

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RCA 930 / 1P40
 RCA 930 / 1P40

Devices included in this entry:

RCA 930 gas-filled phototube
Cetron CE-30C gas-filled phototube


Though identical in construction to the 929 vacuum phototube, the RCA 930 / 1P40 is a gas-filled device with a S-1 spectral response. The 930 is electrically similar to the earlier 918 phototube, but features a standard octal base and a more compact envelope shape.

RCA 930 Datasheet (PDF)

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RCA 931A & 931B
 RCA 931A & 931B

Devices included in this entry:

RCA 931A nine-stage photomultiplier
Sylvania 931A nine-stage photomultiplier
RCA 931B nine-stage photomultiplier


The RCA 931A is the first commercially successful photomultiplier tube, and the first implementation of the popular nine-stage electrostatically focused circular dynode cage structure. Developed in a time before computer simulation, the electrostatic geometry of the 931A dynode cage was determined by placing mechanical models of the electrodes beneath a stretched rubber membrane, with the height of each electrode set to correspond with its electrical potential. Small balls were then placed on the membrane and allowed to roll along the simulated electron path.

The 931A features a S-4 spectral response and a peak sensitivity of 400nm. The 931B is an improved device, with a higher photocathode quantum efficiency and anode sensitivity, and a lower dark current than the 931A.

RCA 931A Datasheet (PDF)

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RCA 1P21
 RCA 1P21

The RCA 1P21 is an early derivative of the 931A, optimized for extreme low-light applications. The 1P21 specification is similar to the 931A, with a S-4 spectral response and a peak sensitivity of 400nm, but the 1P21 has a much higher sensitivity and a much lower maximum anode current. This increased sensitivity is sufficient for detecting individual photons. The 1P21 revolutionized the science of astronomical photometry, as it was capable of precisely measureing a star's intensity. While the earliest 1P21 tubes were specially binned 931A devices, later examples of the 1P21 were purpose-built as a separate part number.

RCA 1P21 Datasheet (PDF)
Gerald E. Kron: The 1P21 (PDF)
RCA Photomultiplier Manual (PDF)

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RCA 1P22
 RCA 1P22

The RCA 1P22 is a 931A-style nine-stage photomultiplier with a response similar to the human eye. The 1P22 has a S-8 spectral response and a peak sensitivity of 420nm.

RCA 1P22 Datasheet (PDF)
RCA Photomultiplier Manual (PDF)

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RCA 1P28 & 1P28A
 RCA 1P28 & 1P28A

Devices included in this entry:

RCA 1P28 9-stage photomultiplier (pictured in thumbnail)
RCA 1P28A 9-stage photomultiplier
EMI 9660B 9-stage photomultiplier
EMI 9781RA 9-stage photomultiplier


The RCA 1P28 is an early 9-stage general purpose photomultiplier designed for the detection of UV and visible light. The 1P28 has an S-5 spectral response, with a peak response at 3400nm. Following the 1P28, RCA introduced the 1P28A, a variant with a higher luminous sensitivity and improved baseline sensitivity above 580nm.

EMI manufactured replacement types for the 1P28 and 1P28A, in both standard and compact base variants.

RCA 1P28 Datasheet (PDF)
RCA 1P28A Bulletin (PDF)
EMI Photomultiplier Tubes (PDF)
EMI Photomultiplier Tubes Supplement (PDF)

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RCA 1P41
 RCA 1P41

The RCA 1P41 is an end-sensing miniature gas-filled phototube optimized to detect infrared light. The 1P41 has a S-1 spectral response and a peak sensitivity of 800nm.

RCA 1P41 Datasheet (PDF)

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RCA 5582
 RCA 5582

The RCA 5582 is superficially identical to the more common 921 cartridge-style gas phototube, but has a S-4 spectral response and 400nm peak sensitivity. The 5582 was used to reproduce sound from a film source.

RCA 5582 Datasheet (PDF)

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RCA 6342A
 RCA 6342A

The 6342A is a design derived from the original RCA circular-cage design, but features a head-on circular semitransparent photocathode and a transversely mounted high current dynode cage. The 6342A has a S-11 spectral response and is intended for use in scintillation counters.

RCA 6342A Datasheet

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RCA 6499
 RCA 6499

The RCA 6499 Radechon is barrier-grid charge storage tube, first produced by RCA in 1956, and used in such venerable systems as the SAGE defense computer. The 6499 uses an electron beam to store data on a charged target. Much like modern DRAM, the contents of memory must be continually refreshed in order to be maintained. The 6499 has a maximum storage capacity of 16,000 random-access bits, though its practical capacity is somewhat less, due to splatter on adjacent bits from the electron beam.

RCA 6499 Datasheet (PDF)

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Sylvania 13-27681-4 'REDBLUE'
 Sylvania 13-27681-4 'REDBLUE'

The 13-27681-4 'REDBLUE' is a circular cage PMT used in Sylvania RGB flying-spot scanners for 35mm slides and 8mm film. Flying-spot scanners use three PMTs, graded for color sensitivity. The 13-27681-4 is suitable for use on red and blue channels.

Special thanks to Mitch Hopper for identifying this device.

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