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Showing results for the phrase "Photographer (Original): Heimnick, John" in Source Type Detail.
- Description
- Beth Dillingham mending blue and white vase in Division of the Orient, Museum of Anthropology.
- Holdings
- 35mm slide: 1909
- Source Type Detail
- Photographer (Original): Heimnick, John
- Description
- Vernon Helmen examining Moccasin Bluff pottery in the Division of the Great Lakes, Museum of Anthropology.
- Holdings
- 35mm slide: 1910
- Source Type Detail
- Photographer (Original): Heimnick, John
- Description
- Left to right: Vernon Helmen, Lillian Hanjian, and Robert Ackerman in the Division of the Great Lakes, Museum of Anthropology.
- Holdings
- 35mm slide: 1911
- Source Type Detail
- Photographer (Original): Heimnick, John
- Description
- Carbon 14 analysis - archaeological specimen presented to Gloria Thornton, chemist, by James B. Griffin. Specimen may be in the form of wood, bone, shell, etc.
- Holdings
- 35mm slide: 1912
- Source Type Detail
- Photographer (Original): Heimnick, John
- Description
- Carbon 14 analysis - the sample is then pulverized and heated in a vycor tube in the presence of oxygen over hot cupric oxide, to oxidize it to carbon dioxide and water.
- Holdings
- 35mm slide: 1913
- Source Type Detail
- Photographer (Original): Heimnick, John
- Description
- Carbon 14 analysis - part of the chemical apparatus used in this project includes oxidation tubes, trays to catch the carbon dioxide and water, and carbon dioxide storage bulbs.
- Holdings
- 35mm slide: 1914
- Source Type Detail
- Photographer (Original): Heimnick, John
- Description
- Carbon 14 analysis - the carbon dioxide, after purification, is passed through an iron tube containing magnesium and is thereby reduced to carbon. This carbon is separated from the magnesium oxides, which were also formed in the iron tube, by means of acid washings, and is then dried to be stored until needed.
- Holdings
- 35mm slide: 1915
- Source Type Detail
- Photographer (Original): Heimnick, John
- Description
- Carbon 14 analysis - the powdered carbon thus produced when mixed with benzene and a small amount of oil can be smeared on the inner surface of a cylinder. The cylinder is spinning while the carbon mixture is poured in. A hair dryer is used to dry the carbon layer. A cylinder, thus prepared, is ready for admittance to the geiger counter.
- Holdings
- 35mm slide: 1916
- Source Type Detail
- Photographer (Original): Heimnick, John
- Description
- Carbon 14 analysis - the carbon is easily removed from the cylinder with a small spatula and may be saved for a check run at a later date. Gloria Thornton
- Holdings
- 35mm slide: 1917
- Source Type Detail
- Photographer (Original): Heimnick, John
- Description
- Carbon 14 analysis - the stainless steel cylinders containing the carbon to be counted are put into the counter.
- Holdings
- 35mm slide: 1918
- Source Type Detail
- Photographer (Original): Heimnick, John
- Description
- Carbon 14 analysis - a close-up of the three cylinders, showing part of the mechanism used for changing automatically their positions inside the counter during operation. One of the cylinders contains the sample whose age is to be measure. The other two contain, respectively, carbon from rice (contemporary) and carbon from coal (ancient), which serve as calibration standards. Only one cylinder may be counted at a given time - namely, the one which
- Holdings
- 35mm slide: 1919
- Source Type Detail
- Photographer (Original): Heimnick, John
- Description
- Carbon 14 analysis - one ton of iron (painted green) and two tons of lead partially shield the counter form cosmic radiation. The counter, which is about six feet long and is inside the shielding, is not visible. So-called "anti-coincidence counters" surround the carbon counter inside the shielding and serve to cancel out most of the cosmic rays which get through the shielding.
- Holdings
- 35mm slide: 1921
- Source Type Detail
- Photographer (Original): Heimnick, John
- Description
- Carbon 14 analysis - a view of the clocks and registers which record the data. At the end of a run, the total amount of time spent on each of the three cylinders and the total number of counts from the carbon inside the cylinder appear on its particular clock and register.
- Holdings
- 35mm slide: 1922
- Source Type Detail
- Photographer (Original): Heimnick, John
- Description
- Carbon 14 analysis - the "scaling circuit" shown is used to monitor the performance of the carbon counter. It records every count from the counter, whether it is due to cosmic radiation, contamination within the laboratory, or the carbon inside the cylinder being coated at the time.
- Holdings
- 35mm slide: 1923
- Source Type Detail
- Photographer (Original): Heimnick, John
- Description
- Carbon 14 analysis - a view of the oscilloscope which may be connected to any point in the electronic circuits to provide a visual indication of the counting rate, the shape of the voltage pulse produced by a count, or the general performance of the circuits.
- Holdings
- 35mm slide: 1924
- Source Type Detail
- Photographer (Original): Heimnick, John
- Description
- Carbon 14 analysis - a view of the oscilloscope which may be connected to any point in the electronic circuits to provide a visual indication of the counting rate, the shape of the voltage pulse produced by a count, or the general performance of the circuits.
- Holdings
- 35mm slide: 1925
- Source Type Detail
- Photographer (Original): Heimnick, John
- Description
- Knowing the half-life of carbon 14, the age of the sample which was counted may be determined from the data on the clocks and registers.
- Holdings
- 35mm slide: 1926
- Source Type Detail
- Photographer (Original): Heimnick, John