Memorandum from Arthur Waltner to Clifford K. Beck

%MurNBneutron101751; ]> Memorandum from Arthur Waltner to Clifford K. Beck Machine readable transcription Waltner, Arthur Creation of machine-readable version: Russell S. Koonts Creation of digital images: Russell S. Koonts Conversion to TEI.2-conformant markup: Russell S. Koonts ca. 9 kilobytes NCSU Libraries Raleigh, NC Modern English, MurNBneutron101751

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23 October, 2000

Nuclear Reactor Digitization Project

Raymond L. Murray Reactor Project Notebook

Illustrations have been included from the print version. Scanned by Russell Koonts with Photoshop 5.0 software. Memorandum from Arthur Waltner to Clifford K. Beck Arthur Waltner

1 p. Manuscript copy consulted UA 105.16

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Library of Congress Subject Headings October 17, 1951 English LCSH manuscript 24-bit color: 400 dpi Memorandum from Arthur Waltner to Clifford K. Beck Typescript 1 p. October 17, 1951 MurNBneutron101751

October 17, 1951 TO: Clifford K. Beck FROM: Arthur Waltner CC: Reactor Committee SUBJECT: Neutron Detectors REFERENCE: Conference, J. E. Bins, BrookhavenNational Laboratory.

A. The Brookhaven reactor does not use fission chambers for measurement and control of the reactor. A few experimental fission counting chambers have been used. These are parallel plate chambers using three circular plates on which. U235 has been deposited electrolytically. These plates are available from the K-25 plant at Oak Ridge.

B. Boron can be most easily deposited on the walls of an ion chamber if it is in the form of an oil slurry. It is available in such a form through the AEC at about $16.00 par grain. Dr. Joseph Gundlach of Oak Ridge has complete informa- tion on this technique.

C. Aluminum, steel, or graphite all make satisfactory chamber material for coating by the above process. Some chambers, in fact, use steel and aluminum in the same chamber. In the judgment of Mr. Bins aluminum is probably better than steel as a chamber material.

D. A normal boron chamber having a diameter of 3 inches and a length of 30 inches produces a current of 270 microamperes, when one end is in a flux of 1011n/cm2 sec. The position of this chamber is such that the flux gradient is great so that the mean flux is considerably less than the stated value.

E. A compensated chamber consisting of two identical chambers, one coated with boron and the other uncoated has been developed to minimize the gamma back- ground. This chamber has a graphite electrode and a magnesium shell. It is observed that this chamber reduces the gamma background by a factor of 107. Information on this chamber is available from Dr. Gundlach of Oak Ridge.

F. It has not been necessary to use rigid coax to the detectors of the Brookhaven Reactor. Ordinary polycthelene coax cable is used.