May 29, 1952

We seem now to have reached general agreement on the complete instrumentation
system desirable for "low level" and "high level" operation of the reactor. There
are yet two items to be clarified: (1) the exact identity of the components in the
system, particularly that of some of the radiation sensory elements, and (2) the
priority of effort on the various channels in the system.

The entire system consists of nine channels. These are designated by number,
to be used subsequently in references to the respective channels:

Channel 1.	For Pulse Measurements, B F3 chamber into a #162 (Nuclear Instr.) scalar, etc.
Channel 2.	For Pulse Measurements, B F3 chamber into a #162 (Nuclear Instr.) scalar, etc.
Channel 3.	For Pulse Measurements, BF3 or fission chamber into - undecided.
Channel 4.	For Pulse Measurements, fission chamber into Atomic Instr. Scalar, etc.
Channel 5.	For gamma ray measurements, scentillation or pressure ionization chamber into appropriate apparatus.
Channel 6.	Boron lined ion chamber directly into console galvanometer.
Channel 7.	Boron lined ion chamber into log amplifier into rate circuit.
Channel 8.	Boron lined ion chamber into preamp into recorder.
Channel 9.	Boron lined ion chamber into preamp into balance vs Nubion Pot. and into Brown amplifier for automatic control of rod. A differ- ence amplifier is connected between Channels 8 and 9.

To the present date, major effort of the instrumentation group has been de-
voted to Channels 7, 8 and 9 with top priority being given to Channels 8 and 9.

The major purpose of this memorandum is to request a re-distriubtion of effort
by the instrumentation group and a realignment of priority of effort onto the in-
strument channels, according to the following schedules:

1.	Lowest priority will be given to Channels 8 and 9. No further work whatever will be done on these channels except as fill-in for effective scheduling when efforts cannot be directed to the other channels.
2.	No further work will be done on Channel 7, except as indicated in 4 be- low, until further word is received from Nuclear Instructorumenton this channel.
3.	Top priority is allocated to Channels 1 to 6, inclusive.

Specifically desired at the earliest possible moment is a block diagram of
each channel showing the recommended components (or alternate recommendations).
Indicate the components which can be purchased and those to be constructed locally.
Usable ranges, safety features, approximate response specifications of each channel
is to be indicated. As soon as each proposed channel is approved by the Reactor
Staff, top priority will be given to preparation of orders on standard Purchase
Requisition forms, for all components to be purchased. Efforts will then be di-
rected to the detailed design and construction of the safety trips, component inter-
connections, console mounting of meters, dials, controls, and all other items to be
performed locally.

4.

A major item in the entire instrumentation system has yet to be settled, and this must be done even before much of the above, that is, establish- ment of the exact identity of the radiation sensory element in each channel. We are in a particularly embarrassing situation regarding elements in Channels 6-9. In late February the recommendation was made by Dr. Underwood, after his trip to Oak Ridge, that the PCP ionization chamber, being the only satisfactory one thus far designed, should be selected. The Reactor Staff group accepted this recommendation and plans were made to build for of these units. However, exceedingly great difficulties, financialphysical and mechanical, have been encountered. It may prove impossible to obtain these chambers before the reactor is ready for operation.

Specifically, the questions are: (1) What alternate choices, for each channel,
are there? (2) If we don't know, how can we find out? If suitable substitutes can-
not be found, how must plans for Channels 6 - 9 be altered?

5.	One of the instrument assistants, Mr. H. L. Turvey, is to be assigned over the summer period to the task of installing the campus monitoring system. Plans should be developed on this system sufficiently in ad- vance that he can be kept effectively engaged on this assignment.

In the overall perspective, all efforts on Reactor construction must be so
scheduled that maximum total progress is achieved. In my judgment, with all factors
considered, the schedule above will most nearly accomplish this. Your cooperation
will be appreciated.