General Information

Serial #

CA6977

Part Number

1

Total Parts

4

AKA

N/A

Patents

N/A

General Description

Glass tube/ Metal wires and parts/ Synthetic top and parts

Dimensions

Note: These reflect the general size for storage and are not necessarily representative of the object's true dimensions.

Length

12.4 cm

Width

N/A

Height

N/A

Thickness

N/A

Weight

N/A

Diameter

3.1 cm

Volume

N/A

Lexicon

Group

Vacuum Tubes

Category

Photoemissive

Sub-Category

N/A

Manufacturer

AKA

Hamamatsu

Country

Japan

State/Province

Unknown

City

Tokyo

Context

Country

Canada

State/Province

Ontario

Period

Hamamatsu's R6095 tube was still for sale in 2011

Canada

A piece of equipment used at the David Dunlap Observatory at the University of Toronto, one of Canada's most important astronomical observatories. The David Dunlap Observatory opened in 1935 as the result of a bequest from the wife of David Dunlap. The telescope was a 74 inch (188 cm) reflector built by Grubb Parsons of Newcastle-upon-Tyne in England. The 74 inch was then the largest telescope in Canada (surpassing the 72 inch telescope of the Dominion Astrophysical Observatory in Victoria) and became the second largest in the world after the 100 inch Hooker Telescope of the Mt. Wilson Observatory outside Los Angeles. DDO's reputation grew and following WWII, it began to graduate most of the astronomers produced in Canada with University of Western Ontario far behind. Beginning in the 1960s a number of other astronomy departments were created but UofT/DDO held its place, a position it probably still holds. The DDO had a good technical staff which gave them an advantage and, with most of the 1940s to early 1970s top astronomers coming from UofT, grants from NRC and then ENSERC were almost guaranteed and allowed UofT's top astronomers -- Hogg, van den Berg, Fernie, Bolton, Kamper, Martin, etc. to acquire or build some of the best equipment available in university observatories. For optical observatories, only the DAO had technical staff and budgets that surpassed those of DDO. In 2007, citing increasing light pollution, the University of Toronto announced plans to sell the Observatory property. In June 2008, it was sold to Corsica Development Inc., a subsidiary of Metrus Development Inc. and the Observatory was closed. In 2009 the Observatory buildings and 80% of the site were designated a cultural heritage landscape. Also in 2009 Corsica and the Royal Astronomical Society of Canada, Toronto Centre announced an agreement allowing the RASC to provide public education and outreach programs at the observatory, and to operate the 188 cm telescope.

Function

A photomultiplier tube is a vacuum tube, specifically a phototube, that is an extremely sensitive detector of light in the ultraviolet, visible, and near-infrared ranges of the electromagnetic spectrum. This example would have been used in an astronomical observatory in a photometer, an instrument used to measure the brightness of stars, galaxies and other astronomical bodies with great accuracy.

Technical

An example of a photomultiplier tube used with one of the several photometers in this collection which show the development from the simplest (this one, which was probably built prior to Fernie's arrival at DDO) with a single PM tube, to those with multiple tubes monitoring the sky and star simultaneously to the set used in recent years simultaneously on both the 19 and 24 inch telescopes [2008.0197 and 2008.0198] on the DDO administration building.

Area Notes

Unknown

Details

Markings

Silver label on tube reads in black and silver 'R6095/ NO. CA6977/ HAMAMATSU/ PHOTOMULTIPLIER TUBE/ MADE IN CHINA'

Missing

Appears complete

Finish

Colourless transparent and silvered glass/ Plated metal/ Black cap/ Maroon synthetic parts

Decoration

N/A