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Group 10 - The following items were shipped to Scioto Laboratory: 6 Thyratron Heater Controls (TR-1-A), 2 Switch Boxes (for P & E), 1 Log Amplifier (AM-1); 1 Pulse Generator (PG-1-B). The following are completed, tested, and awaiting transportation: 3 Two-Input B-wall Mixers (MX-2-A), 1 Pulse Generator (PG-1-B),1 Regulation Checker (RC-1) (for plating control power supplies), 1 Preamplifier (AM-2) (for Berkeley decimal scaler). The following are under construction: 6 Pulse Generators (PG-1-B) (for Health Division) (EO-508) 90%, 10 Switch Boxes (8 for P & E, Scioto, 2 for P& E, "T" Building) 85%, 6 Junction Boxes (for P&E, "T" Building, EO-486) 90%, 2 Four-Input G. M. Mixers. One on EO-17, one from Unit III. The mixers have been finished and tested for some time. The scalers (Nuclear Instrument Model 161-G) have just been received and are being modified for use with the mixers. A prototype preamplifier for the Berkeley decimal scaler was constructed and tested. Group 11 - A special pulse generator having output pulses fixed in time, and adjacent pulses variable in time with respect to the fixed pulse is under development. An initial mock-up of such a generator showed promise in that the variable pulses could be shifted …

This semiannual report includes references in future items in the Brookhaven National Labratory program as well as an account of progress in the post six months.

An experimental range-energy relation in Ilford C-2 emulsion has been obtained for proteins up to 39.5 Mev. In the region from 17 to 33 Mev the relation for dry emulsion is fitted by the empirical equation E{sub (MeV)} = 0.251 R{sub ({mu})} 0.581. Variations in water content due to changes in atmospheric humidity make several percent difference in range. The range in Ilford glass is found to be 18 {+-} 4 percent longer than in dry C-2 emulsion.

The quartz-fiber microbalances used in the Mound Laboratory operations are of the conventional Kirk-Craig type, but are housed in vacuum-tight cases which permit foil weighing by remote control.

This paper is a compilation of the essential results of our experimental work in the determination of the path of carbon in photosynthesis. There are discussions of the dark fixation of photosynthesis and methods of separation and identification including paper chromatography and radioautography. The definition of the path of carbon in photosynthesis by the distribution of radioactivity Within the compounds is described.

The general principles of a liquid-liquid solvent extraction method for the separation of metallic elements are outlined.

The decomposition of diacetyl peroxide in acetic acid-2-C{sup 14} has been studied, The activity of the products in general confirmed the mechanism of the reaction as proposed by Kharasch and Gladstone, The presence and distribution of activity in the methyl acetate produced in this reaction is not explained by the previously proposed mechanism. There was no appreciable exchange of acetic acid and diacetyl peroxide under the conditions of the reaction. Essentially no exchange of methyl acetate and acetic acid was observed when those reagents mere heated at 100 for five hours.

The relationship of respiration to photosynthesis in barley seedling leaves and the algae, Chlorella and Scenedesmus, has been investigated using radioactive carbon dioxide and the techniques of paper chromatography and radioautography. The plants are allowed to photosynthesize normally for thirty seconds in c{sup 14}O{sub 2} after which they are allowed to respire in air or helium in the light or dark. Respiration of photosynthetic intermediates as evidenced by the appearance of labeled glutomic, isocitric, fumaric and succinic acids is slower in the light than in the dark. Labeled glycolic acid is observed in barley and algae. It disappears rapidly in the dark and is maintained and increased in quantity in the light in C0{sub 2}-free air.

The study was made in an effort to determine experimentally the relationship between Logac 1,2 counts and the thickness of the slide on which a sample is mounted.

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A device for manipulating a pair of tongs behind a shielding barrier has been built and tested. It is called a Master-Slave Manipulator because the slave tongs move in exact correspondence with a master handle. The "slave hands" follow the master hands in complete synchronism. This is the first completely master-slave manipulator known to exist and has proved that this type of manipulation is very successful when the unit is prooperly engineered and built.

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A high resolution scale-of-four has been developed to be used in conjunction with the nuclear particle detection devices in applications where the counting rate is unusually high. Specifically, it is intended to preceed the commercially available medium resolution scaling circuits and so decrease the resolving time of the counting system. The circuit will function reliably on continuously recurring pulses separated by less than 0.1 μ sec. It will resolve two pulses (occuring at a moderate repetition rate) which are spaced at 0.04 μ sec. A five-volt input signal is sufficient to actuate the device.

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The extension of the passband of wideband amplifiers is a highly important problem to the designer of electronic circuits. Throughout the electronics industry and in many research programs in physics and allied fields where extensive use is made of video amplifiers, the foremost requirement is a passband of maximum width. This is necessary if it is desired to achieve a more faithful reproduction of transient wave forms, a btter time resolution in physical measurements, or perhaps just a wider band gain-frequency response to sine wave signals. The art of electronics is continually faced with this omnipresent amplifier problem. In particular, the instrumentation techniques of nuclear physics require amplifiers with short rise times, a high degree of gain stability, and a linear response to high signal levels. While the distributed amplifier{sup 1} may solve the problems of those seeking only a wide passband, the requirements of stability and linearity necessitate using feedback circuits. This paper considers feedback amplifiers from the standpoint of high-frequency performance. The circuit conditions for optimum steady-state (sinusoidal) and transient response are derived and practical circuits (both interstage and output) are presented which fulfill these conditions. In general, the results obtained may be applied to the low-frequency end. …

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Physical and inorganic Chemistry. Studies are reported on: volatile complexes of ZrCl/sub 4/ and HfCl/sub 4/ with POCl/sub 3/; reaction of UCl/sub 4/ with LiAlH/sub 4/; preparation and properties of metal uranates and polyuranates; heats of solution of UO/sub 2/(NO/sub 3/)/sub 2/ hydrates; absorption spectra of Np in HClO/sub 4/, and separation of Np and Pu chlorides by a flow method. Process Chemistry. Extraction of Th from Mailiackrodt U raffinate was studied. Nuclear Chemistry aad Radiochemistry. Invesigations were carried out on: organic tritium; exchange reactions of U ions in solution; exchange reactions of Fe in aqueous solutions: Tc recovery from old Hanford slugs; (a,2n) cross section of Pa/sup 231/; and spontaneous fission counting U/sup 236/ and Pu/sup 238. (T.R.H) l822 Nuclear Chemistry and Radiochemistry. Measurements of the half- lives of Ac/sup 227/ and RaD(Pb/sup 210/) were continued. The effective pile neutron capture cross sections for U/sup 236/ were determined by measuring the activity of the resultant U/sup 237/ with an end window geiger counter. A study of ion chambers for tritium analysis is presented. Procedures were developed for the determination of tritium and C/sup 14/ in onganic compounds. Physical and Inorganic Chemistry. An investigation of the electrochemistry of Np in …

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