Trip Report-Visit to CERN July 5 to August 5, 1985

The present visit to CERN was as a result of an invitation from Dr. Colin Johnson of the Antiproton Accumulator (AA) group. Two activities were planned for this visit. First, the second beam test of one of the original Fermilab lithium lenses (serial No.2). Second, the installation and beam tests for a new Fermilab lens of improved design (serial No.5). It should be mentioned here that CERN, after realizing the possible gains to be obtained, has started a considerable development effort in short focal length lenses. Presently they have 3 operational lithium lenses, transformers and power supplies for tests. They are in the process of constructing 3 other transformers and designing lenses of 4 cm diameter (twice the present Fermilab lenses). Fermilab should devote some added effort in the field to maintain the initiative. The first beam test of lens No.2 was performed during the summer of 1983, when the lens was used as an antiproton collecting lens. For this test the original lens was used as a strong focusing element in the 26 GeV proton beam in conjunction with a current carrying target Preliminary tests for this geometry were conducted during 1984, when the lens was exposed to over 2*E6 pulses at 320kAmps and 1.3*E13 protons per pulse. Lens No.5 was installed as an antiproton collecting lens, immediately following the AA production target, in a geometry similar to the one designed for the Tevatron 1 project at Fermilab. Targets of a different design than the one use normally at CERN were also required. After completion of the antiproton yield measurements and optimization the lens was left in the beam during regular operation for antiproton accumulation. During antiproton accumulation for the Lear accelerator new records were achieved on the accumulation yield and accumulation rate of antiprotons for the AA machine. CERN activities in the development of a Plasma Lens, as an alternative to the lithium ones, and new broad band pick-ups for stochastic cooling were observed as they are of great interests to Fermilab