- -~- - . eo . . . aoe te gS WaTno. Ala woe Port Vil Physical Research PHYSICS (UNCLASSIFIED) 4 eC sage “UNCLASSIFIED — . a, re ae Improvement of the CP-5 Research Reactor a . ° Additional top shielding was installed on the CP-5 reactor in April, as part of the modifi- a S72 Ee. _ es a red. : ae ‘ - cation authorized for fiscal year 1958. To test the reactor’s operating characteristics at higher power, it was scbsequently operated for 2 hours at 5,000 kilowatts and performed satisfactorily In all respects. , The reactor was originally operated in 1954 at a power level of 1,000 kilowatts. This level was Increased to 2,000 Hlowatts in 1957, and improvements to permit operation at 4,000 Kilowatts were authorized by Congress a year ago. Authority for additional modifications to permit operation at 10,000 kilowatts was included in the fiscal year 1959 authorization request. Bevatron Breakdown ' a i . 4 -‘ ; On April 23 one of the two motor generators. which power the magnet coils of the Bevatron at Berkeley broke down when the head of a retaining bolt sheared off. Repair of the generator ata cost of $150,000 was expected to be completed in July. Following inspection of the other generator, routine operation of the Bevatron was resumed, 24 hours a day and 7 days a week, but at less than the normal pulse rate of 10 pulses per minute and at proton energies less than the 6.3 billion electron volts (Bev) usually attained. The reduced energy level of the machine did not permit simultaneous research operation at both target Stations. E 3 Before the breakdown occurred, an unusually large number of antiproton events had been ‘| a 4 observed with the new 15-inch hydrogen bubble chamber. At the reduced pulse rate and energy, it Was necessary to undertake other types of experiments, pending resumption of normal opera- t an tion.* i- 4 72-Inch Bubble Chamber _ 4 ae = ae “sq ‘ i * Development continued of the 72-inch bubble chamber for the Bevatron. In early May, the : magnet for the device was “walked” into its new building. Because of its great weight, more : than 200 tons, the magnet is equipped with hydraulically operated pads to move the system in ' a step-by-step fashion at a rate of about one foot per minute. In this way the bubble chamber ¢ can be moved from one beam of the Bevatron to another. i DOE ARCHIVES * All generetor repairs were completed and the Bevatron resumed full power operation on July 18. : 34 ‘ enn t apart UNCLASSIFIED ay ~ ay yp pager 28 ‘ ‘, i ott f wes [Ess , og ct 49 > e: __ 5 | -