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UNIVERSITY OF COPENHAGEN
unit of dosage all over the country by paying regular visits to the different x-ray departments.
The permanent staff comprises the professor, three scientific assistants (two full-time, and one half-time), one half-time clerk, one mechanic, and a boy in the workshop.
The annual budget available for laboratory purposes amounts to 6,400 kroner plus about 2,000 kroner from the students besides the sums necessary for electricity and gas supply and for cleaning.
The rooms (compare the plans) are situated in the basement and first floor in the western part of the middle wing. Besides the rooms shown in the plans the laboratory has two rooms in the sub-basement for work requiring very solid foundations or constant temperature.
The general equipment of the laboratory rooms is as described before. Of the rooms only a few present special features. The large teaching laboratory with two small adjacent dark rooms for optical work has accommodation for twenty-four students and is used every day. For research purposes eight to nine rooms are available.
The large x-ray room in the first floor (Fig. 4) is equipped with a special Siemens “Polyphos” apparatus
which can give constant high tension from very low values up to 220 KV (the Greinacher arrangement with two condensers in series and two rectifying tubes) as well as rectified non-constant high-power tension up to 110 KV (four rectifying tubes). This apparatus is placed in an adjacent room from which the high tension can also be used in the large lecture-theater. As the switchboard table cannot be taken into the theater we have a special telephone connection to this table and ammeters in both places. In case of accident the circuit can be broken also in the theater. In the large x-ray room we have for the x-ray tube a wooden box 2.25 by 1 by 1 meters (Fig. 10) covered with 5 mm lead and with special suction for working with hard rays. From this box the rays can be used both horizontally and vertically. Other working places are arranged for radiographic work and for special work.
In the basement in a special large cupboard between two rooms is placed a smaller high tension apparatus (“ Spectral-Konstant ” with rotating rectifier) allowing in addition to the same arrangements as the Polyphos, the Hull arrangement with condensers parallel and one pole grounded.
In some of the rooms in the basement and sub-base-
Fig. 10.—Section of Biophysics Laboratory