[en] Our MP7 accelerator has had about 70% utilization in the past year, clocking 6000 hours, of which approximately 10% was at terminal voltages between 14.75 and 16.25 MV. This pelletron system, installed in 1977, has logged 40,000 hours, and to date has broken five chains, three in the past four months. There are still two chains that have gone the total time. The injector machine, MP6, with its three chains installed in 1980, has accumulated 18000 hours with no chain failures. About six percent of the operating time in the past year was devoted to four-stage operation or accel-decel production of low energy highly stripped ions, for atomic physics experiments. This type of operation was improved by the addition of a remotely inserted gridded lens at the exit of the special last acceleration tube. Some examples of the beams we have produced are 2.5 MeV ³⁵Cl, Q16 10 na, 8 MeV ³²S, Q15 .5 na, 2.5 MeV ¹⁹F, 09 20 na. We have acquired two General Ionex 860, Roy Middleton Mark VII sputter sources. One of these we have mounted on an ion pump, with integral focus lens, steerers and perture, and dedicated it to ¹⁴C use, for injection into MP7. To date, from June, we have used it for four runs totaling 32 8-hour shifts, and 116 μa hours, with a maximum injected beam of 2.5 μa. The other 860 sputter source was used in a pulse mode to test for possible injection of the tandem accelerated heavy ion beam into BNL's AGS

[en] Operation of the Brookhaven MP-7 tandem Van de Graaff accelerator with pure SF₆ insulating gas is described. Sparking and terminal voltage were monitored and are compared for operation with a mixture of SF₆, N₂, CO₂ and O₂. The accelerator was found to be more difficult to operate with pure SF₆

[en] Performance of the two tandem accelerators, MP7 and MP6 is described. The MPG was converted to a Pelletron charging system, and the reliability after 13,500 hours is discussed. An incident in which Phosphorus 32 was detected in the MP7 led to the conclusion that it resulted from the nuclear reaction ₃₂S(n,p)₃₂P, occurring in the insulating gas during acceleration of a D² beam

[en] A statistical analysis is presented comparing terminal voltage capability of the MP-7 tandem Van de Graaff accelerator with pure SF₆ insulating gas or with a mixture of 50% SF₆, 40% N₂, 6% CO₂ and 4% O₂

[en] The three-stage tandem accelerator facility at Brookhaven National Laboratory (BNL) consists of two model MP tandem Van de Graaff accelerators arranged in line so that MP-6 can inject negative ions up to 10 MeV energy into MP-7 providing a three stage mode of operation. The injector accelerator, MP-6, may also be used as a standard two-stage accelerator having been equipped with an external ion source and target room facility. A description is given of recent improvements and current operating status and performance. Improvements in operation have now provided record electrostatic accelerator heavy ion energies for the research program of 125 MeV ¹⁶O⁸⁺ 200 MeV ³²S16⁺ and 255 MeV ⁶³Cu¹⁹⁺

[en] The three-stage Tandem Van de Graaff accelerator facility at Brookhaven National Laboratory has undergone various upgrading programs since the early 1970's. The original 10 MV waranteed MP Van de Graaff accelerator of 1970 now operates in excess of 14 MV because of many improvements over the years: the purpose of this paper is to report on the most recent improvements which have been completed and also on those that are presently under construction and being implemented

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[en] The main features of the six North American MP tandem Van de Graaff accelerators are summarized as well as some of their main performance characteristics. The latest accelerator-related studies, developments and improvements are described for each facility. Ongoing and proposed future developments at some of these laboratories are briefly discussed. (orig.)