The Vintage Technology Association

Detection Tubes

This section includes a range of detection devices, primarily photomultipliers and phototubes. 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.

Varian 0981-82850-301

The Varian 0981-82850-301 is a thoria iridium ion source for use in Varian gas detectors. The device is barely a vacuum tube, as it has no glass envelope; the envelope for the tube remains attached to the gas detector. To protect the ion source from a world of dirty humans, the device is shipped in a protective plastic cylinder, which contains stern warnings to handle the device by its base only.

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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 side-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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Hamamatsu R1250

The R1250, with a length of 10 inches and a diameter of 130mm, is a monster of a photomultiplier. This tube, designed for use in scintillation counters, is a 14 stage device with a peak spectral response of 420nm. The tube uses a large 20 pin base, sockets are undoubtedly hard to find.

[View Detail]

Honeywell 113228

This long narrow device is a special type of phototube, designed to detect UV light. Unlike most phototubes which have an argon fill, this tube is filled with neon. The 113228 is used exclusively in Honeywell Purple Peeper and Mini Peeper industrial flame sensors. It can be difficult to find sockets for the small three-pin base.

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Sylvania 13-27681-4 'REDBLUE'

We have no idea what this is; it's a standard circular-cage model, with a strange part number.

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RCA 1P21

The 1P21 is a side-viewing photomultiplier designed for extremely low light applications. The tube has a lime glass envelope, a humidity-stable beige base, and outputs maximium amplification at 380 nanometers. This tube is capable of detecting single photons, and will be destroyed if powered up while exposed to ambient light.

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RCA 1P22

Circular cage PMT with spectral response similar to the human eye. Less sensitive than the 1P21.

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RCA 1P40

The 1P40 is a fairly standard example of a cold cathode phototube. The tube contains a curved photosensitive cathode and a centrally located anode. The tube is lightly pressurized with an argon fill gas to enhance conditions inside the tube. This tube has a standard octal base.

GM Labs #2 'Visitron'

'Visitron' is yet another brand name concocted by the tube companies to take a boring argon filled phototube and make it sound new and exciting to the consumer. Despite the goofy name, the tube itself is actually quite attractive, with a large curved envelope and a four-pin phenolic base. The tube's serial number is 304,279.

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RCA 1P41

The 1P41 is an end-viewing miniature phototube with a three pin base. The tube has a spectral response S-1 and an argon fill gas. According to RCA, this tube is intended for relay applications.

A scan of the RCA Photosensitive Devices and Cathode Ray Tubes catalog, which contains specifications on this tube, can be found at World Power Systems.

[View Detail]

RCA 921

The 921 is a side-viewing phototube with an argon fill gas. The tube has an unusual form factor, with two metal caps sealed to a glass tube. Each cap acts as one pin for the device. As with the 1P41, this tube is intended for relay applications.

A scan of the RCA Photosensitive Devices and Cathode Ray Tubes catalog, which contains specifications on this tube, can be found at World Power Systems.

[View Detail]

RCA 931A

The 931A is a side viewing, nine-stage photomultiplier, an improved version of the original 931. Tubes of this type do not produce an image; instead they are designed to measure and amplify very weak sources of light. This tube was manufactured with both a black and tan bases. The tan base is made of a special material that is more resistant to humidity, and as such is more desirable than the black base variant.

RCA 931B

931 variant with improved spectral response and quantum efficiency.

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RCA 991

The 991 is primarily used as a voltage regulator, but has also been known to be used as a phototube in some situations. Unlike most phototubes which use argon as their fill gas, the 991 has a neon fill. The 991 can also double as a neon indicator.

Raytheon A704

With an envelope size of just over an inch, the A704 is one of the smallest phototubes ever made. This tiny two pin tube does not even have any discrete internal components, the photocathode is just a chemical, most likely a lead sulfide photoconductor, painted onto the back wall of the envelope. The tube has an argon fill gas.

Cetron CE-36

Here is another miniature phototube with a three pin base. The CE-36 is a side view tube with an argon fill gas. According to the book Tube Lore, this is a spectral response S-1 tube commonly used in projectors.

Amperex PM-2412B

Top-sensing, 3" window dia.

Photonis XP2412B Datasheet

[View Detail]

Hamamatsu R444

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

[View Detail]

Hamamatsu R488

The R488 is an end-view phototube designed to be extra sensitive to UV light. Unlike most other phototubes, which have an argon fill gas, the R488 is a hard vacuum tube.

Hamamatsu R928

The R928 is a nearly modern incarnation of the classic circular cage-type PMT. The R928 features a 185-900 nm spectral response, a proprietary multialkali photocathode and 25.4% peak quantum efficiency.

Hamamatsu R928 Datasheet
[View Detail]

Valvo 90AG

A British made argon filled phototube in a standard seven pin envelope. This tube has particularly good print quality on its part number and logo, it is not quite up to the standard set by Western Electric tubes, but is far better than the typical "dissolves when looked at" print used on most tubes.

[View Detail]

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 side-mounted high current dynode cage. The 6342A has a S-11 spectral response and is intended for use in scintillation counters. RCA 6342A Datasheet [View Detail]

Hamamatsu R1250
	The R1250, with a length of 10 inches and a diameter of 130mm, is a monster of a photomultiplier. This tube, designed for use in scintillation counters, is a 14 stage device with a peak spectral response of 420nm. The tube uses a large 20 pin base, sockets are undoubtedly hard to find. [View Detail]

Honeywell 113228
	This long narrow device is a special type of phototube, designed to detect UV light. Unlike most phototubes which have an argon fill, this tube is filled with neon. The 113228 is used exclusively in Honeywell Purple Peeper and Mini Peeper industrial flame sensors. It can be difficult to find sockets for the small three-pin base. [View Detail]

Sylvania 13-27681-4 'REDBLUE'
	We have no idea what this is; it's a standard circular-cage model, with a strange part number. [View Detail]

RCA 1P21
	The 1P21 is a side-viewing photomultiplier designed for extremely low light applications. The tube has a lime glass envelope, a humidity-stable beige base, and outputs maximium amplification at 380 nanometers. This tube is capable of detecting single photons, and will be destroyed if powered up while exposed to ambient light. [View Detail]

RCA 1P22
	Circular cage PMT with spectral response similar to the human eye. Less sensitive than the 1P21. [View Detail]

RCA 1P40
	The 1P40 is a fairly standard example of a cold cathode phototube. The tube contains a curved photosensitive cathode and a centrally located anode. The tube is lightly pressurized with an argon fill gas to enhance conditions inside the tube. This tube has a standard octal base.

GM Labs #2 'Visitron'
	'Visitron' is yet another brand name concocted by the tube companies to take a boring argon filled phototube and make it sound new and exciting to the consumer. Despite the goofy name, the tube itself is actually quite attractive, with a large curved envelope and a four-pin phenolic base. The tube's serial number is 304,279. [View Detail]

RCA 1P41
	The 1P41 is an end-viewing miniature phototube with a three pin base. The tube has a spectral response S-1 and an argon fill gas. According to RCA, this tube is intended for relay applications. A scan of the RCA Photosensitive Devices and Cathode Ray Tubes catalog, which contains specifications on this tube, can be found at World Power Systems. [View Detail]

RCA 931B
	931 variant with improved spectral response and quantum efficiency. [View Detail]

RCA 991
	The 991 is primarily used as a voltage regulator, but has also been known to be used as a phototube in some situations. Unlike most phototubes which use argon as their fill gas, the 991 has a neon fill. The 991 can also double as a neon indicator.

Raytheon A704
	With an envelope size of just over an inch, the A704 is one of the smallest phototubes ever made. This tiny two pin tube does not even have any discrete internal components, the photocathode is just a chemical, most likely a lead sulfide photoconductor, painted onto the back wall of the envelope. The tube has an argon fill gas.

Cetron CE-36
	Here is another miniature phototube with a three pin base. The CE-36 is a side view tube with an argon fill gas. According to the book Tube Lore, this is a spectral response S-1 tube commonly used in projectors.

Amperex PM-2412B
	Top-sensing, 3" window dia. Photonis XP2412B Datasheet [View Detail]

Hamamatsu R444
	The Hamamatsu R444 is the ultimate evolution of RCA's original nine-stage design. The R444 has a conventional circular cage of dynodes, scaled down to sub-miniature size. The R444 has a 340nm peak sensitivity. [View Detail]

Hamamatsu R488
	The R488 is an end-view phototube designed to be extra sensitive to UV light. Unlike most other phototubes, which have an argon fill gas, the R488 is a hard vacuum tube.

Hamamatsu R928
	The R928 is a nearly modern incarnation of the classic circular cage-type PMT. The R928 features a 185-900 nm spectral response, a proprietary multialkali photocathode and 25.4% peak quantum efficiency. Hamamatsu R928 Datasheet [View Detail]

Valvo 90AG
	A British made argon filled phototube in a standard seven pin envelope. This tube has particularly good print quality on its part number and logo, it is not quite up to the standard set by Western Electric tubes, but is far better than the typical "dissolves when looked at" print used on most tubes. [View Detail]