TRISTAN inauguration

Tetsuji Nishikawa, Director General of the Japanese KEK Laboratory, addresses the official inauguration ceremony for the new TRISTAN electron-positron collider on 7 April.

On 7 April, the floor of the Tsuku- ba experimental hall at the Japa­ nese KEK Laboratory was filled with proud KEK staff and with offi­ cial representatives from Japan and overseas for the formal dedi­ cation of the TRISTAN electron- positron collider. In November last year, just five years after groundbreaking for the 3 kilometre ring, first electron- positron collisions were observed with 24 GeV beams, at the time the world's highest electron-posi­ tron collision energy. This heroic achievement propelled Japan and the KEK Laboratory into the front rank of world high energy physics, and the speeches at the dedication ceremony reflected the pride of the machine's instigators, builders and users, and the admiration of Laboratory is its first example. It many universities and research the world high energy community. also is one of the first research institutes both in our country and KEK Director General Tetsuji institutes in the newly founded further afield. Nishikawa described the long road Science City of Tsukuba. A propo­ TRISTAN required a lot of ultra- leading to TRISTAN: 'Cyclotrons sal for TRISTAN was presented large equipment built with ultra­ built in this country by the late in 1973, three years before the high precision. To meet this re­ Professors Yoshio Nishina and laboratory's 12 GeV proton syn­ quirement, Japanese industry con­ Seishi Kikuchi and their coworkers chrotron was completed. As inter­ tributed its best, and this effort were unfortunately destroyed and disciplinary collaborative research was behind the completion of the sunk in Tokyo and Osaka Bay facilities arrived, enthusiasm machine on schedule.' respectively right after the war, mounted for an accelerator capable After congratulating the ma­ consequently keeping Japanese of reaching the very frontier of chine's builders. Minister of experimental physics with high elementary particle physics. In Education, Science and Culture energy accelerators behind the 1981, on the tenth anniversary of Masajura Shiokawa underlined his world frontier of the field for a long KEK, we were able to start con­ support for basic research: Today, time. In 1952, the Peace Treaty struction of a 3 km circumference when society is becoming more was ratified, and in 1955, thanks electron-positron collider, a truly and more sophisticated and com­ to the zeal and efforts of our se­ national project. plex, it has become an urgent and niors, the Institute for Nuclear Construction of TRISTAN was important task to build a firm basis Study attached to the University completed in just five years. We for every academic discipline with of Tokyo was founded and con­ thank deeply the members of the the advancement of basic research. struction of a 1 GeV electron parliament and the government, The Ministry of Education, Science synchrotron followed. This, I would the administrative officers who did and Culture has been actively striv­ say, initiated Japanese high energy not spare their support for pure ing to promote scientific research. physics. fundamental science, despite na­ Above all, as one of the major Since then, after much dis­ tional financial difficulties. Con­ directions for the promotion of cussion and effort, a totally new struction was driven not only by important basic research, the min­ type of research organization was a united research, engineering and istry has given a strong support introduced, the National Inter-Uni­ administrative effort, but also by to accelerator science whose pur­ versity Research Institute, and our the support and cooperation of pose is the elucidation of the ulti-

CERN Courier, July/August 1987 3 Good track-fitting fast. The first example of electron-positron annihilation into hadrons Chief director of the TRISTAN project seen at TRISTAN by the VENUS detector Satoshi Ozaki — 'the commissioning went last November. smoothly with lots of difficulties!'

In initial runs with 25 GeV beams, TRISTAN'S average colli­ mate structure of the matter. of human endeavour and are deep­ sion luminosity figure was When one considers the pros­ ly grateful to our governments and 3 x 10 29 cm"2 s"1, with a maximum pect of Japan, approaching the leaders who have the vision to of 2 x 1030. The machine's vacuum 21st century, a further promotion support this basic research. Our system has been improved to re­ of advanced and basic scientific fantastic progress has come duce beam-gas background and research is, needless to say, the through the genuine collaboration extend the beam lifetime. Titanium most vital task which the entire of scientists from many countries wire is now used instead of alu­ country has to tackle for achieving with different social and political minium on the distributed ion a more prosperous society and backgrounds — and surely our pump. Some heating problems in national life.' success must inspire all of us to the electrostatic beam separators For the international community, also push for similar successes on have also been ironed out. Karl Strauch, Secretary of the Com­ broader, more social and political The plan is to continue at mission on Particles and Fields of questions.' 25 GeV per beam using radiofre- the International Union of Pure and Applied Physics (IUPAP), read a message from Italo Mannelli, the Chairman of both the IUPAP Com­ mission and CERN's Scientific Pol­ icy Committee. After recalling ear­ lier such inaugurations, Strauch emphasized the international as­ pect of this research: 'As high energy physicists, we are most fortunate to be able to be involved in one of the most exciting fields

A three-jet hadronic event seen by the multinational AMY group (Japan / US / Korea / China). contains a small detector for a particle search (the SHIP experi­ New Japanese project ment), but could eventually accom­ modate a new detector as and when future research requirements Participants at a recent Inter­ the pioneer work at KEK using become clear. national Workshop in Santa Fe, pulsed meson and neutron Other new physics opportunities New Mexico, heard plans for a beams as matter probes, and could come from an as yet unused new Japanese Hadron Facility to continue the Japanese invol­ experimental area in the 377 m- project to be sited at the nation­ vement in radioactive beam circumference Accumulation Ring al KEK Laboratory (see April physics initiated at the Berkeley which takes particles to between issue, page 24). The plan envis­ Bevalac. 6.5 and 8 GeV prior to injection ages a 1 GeV proton linac, a The new scheme is also seen into "TRISTAN'S main ring. separate linac to handle heavy as a joint venture for KEK and ions, a 2 GeV rapid cycling high Tokyo's Institute for Nuclear intensity proton synchrotron, Study, the birthplace of Japa­ and a slow cycling stretch­ nese high energy physics, but er/synchrotron hybrid ring capa­ which has been lacking a new ble of taking ions to 1 GeV per project for some time. nucléon or protons to 3 GeV. Although the JHF scheme is After the demise of the Numa­ still a proposal, Japanese phy­ tron heavy ion project in the sicists are confident that an ini­ face of the buildup for the TRIS­ tial configuration, not necessarily TAN electron-positron collider the full project as proposed, at KEK, Japanese nuclear phy­ could emerge and get underway sicists carefully prepared a new fairly quickly, continuing the project for intermediate energy rapid rate of development in physics and for interdisciplinary Japanese fundamental physics. science. It aims to capitalize on

quency accelerating equipment in detector is in the ring for the first two of the machine's four straight time, while the VENUS detector sections, although some additional which recorded the first TRISTAN equipment has been installed to collisions is now almost complete. underpin 25 GeV working. Sub­ From the initial runs, VENUS re­ sequently, r.f equipment will be corded 1.4 million triggers, includ­ installed in a third straight section ing 16 events where the electron- to boost beam energy by several positron collisions produced ha- GeV. dronic (strongly interacting) parti­ For the future, superconducting cles. r.f. equipment is foreseen for the Examples of hadronic events fourth straight section, taking to have also been recorded by the beam energy to 33 GeV. Any AMY detector operated by a mul­ further increase in beam energy tinational Japan / US / China / would require the replacement of Korea group. AMY instrumentation conventional r.f. by superconduct­ was pratically complete earlier this ing equipment. year, and the plan is now to use The four TRISTAN detectors are the full 3 T field of the supercon­ in good shape for the ongoing phy­ ducting magnet. sics programme. The big TOPAZ The fourth experimental area