At the time our instrumentation plans were started a search of manufacturer's catalogues did not reveal any suitable ioniztion chamber as being commercially available. Drawings for the B10 chamber designed at the Oak Ridge National Laboratories were obtained. The drawings were studied carefully by Dr. Waltner and myself and performance characteristics were discussed with P. R. Bell and W H Jordon. It appeared as if this chamber was the most suitable one for us to use. Three aspects of the chamber present special problems. 1. The metal parts are of magnesium and special machining techniques are necessary to avoid the fire hazard. 2. The technique of applying the Boron 10 coating requires the induction heating of the graphite parts in an inert atmosphere. 3. The quartz insulation must be fabricated by the General Electric Co. Also it is difficult to machine thhe graphite parts in such a fashion that pits are avoided. The construction of two chambers was started in the machine shop of Engineering Research. It was recently learned that Radiation Counters Laboratory is making some of these chambers for the A. E. C. and that they will make two for us at 1295 dollars each. In view of the above mentioned problems, it is believed that we would do well to purchase two of these ion chambers from R C L. This will ensure us having two operating chambers on hand (delivery date quoted was in October for an order placed in August) and thus avoid a likely time delay in operating the reactor due to difficulties arising in our construction of the chambers. It is therefore recommended that two of the chambers be obtained as soon as possible from R C L.