The 18th Particle Accelerator Conference was held at the Marriott Marquis Hotel, New York City, New York, from March 29 to April 2, 1999, under the joint auspices of the Nuclear and Plasma Sciences Society of the IEEE, and the Division of Physics of Beams of the APS.

Here is a bit of history of the Particle Accelerator Conference as related by Louis Costrell of the National Institute of Standards and Technology and a member of the PAC Organizing Committee. In 1963 Bob Livingston of the Oak Ridge National Laboratory, who was then President of the IEEE Nuclear Science Society (NSS) now the Nuclear and Plasma Sciences Society (NPSS) called Lou to discuss the feasibility of initiating an IEEE/NSS series of conferences on Particle Accelerator Engineering. They then proceeded to organize the first such conference that was held March 10-12, 1965 at the Shoreham Hotel in Washington DC and drew 750 participants. In 1993 the IEEE/NPSS and American Physical Society, Division of Physics of Beams, signed a Memorandum of Understanding for joint sponsorship of the Particle Accelerator Conference, beginning with PAC'95. Concerning the locations: the first three conferences were held in Washington DC, then the conference started rotating between the East, Central and Western areas. The location statistics up to 1997 are as follows: Washington, 6. San F rancisco, 3. Chicago, 3. Vancouver, 2. Santa Fe, 1. Dallas, 1.

PAC'99 was the first time the meeting has been held in New York, and Brookhaven National Laboratory was honored to have been chosen as host. The attendance (1338) was as anticipated, up 10% from the 1997 Vancouver meeting and up 25% from the 1995 Dallas meeting, indicating the continuing vitality of the discipline even in these fiscally stringent times. The international component is also growing, with 34% of the delegates coming from 29 countries outside North America.

PAC'99 marks the completion of the construction of the BNL Relativistic Heavy Ion Collider (RHIC) which started its commissioning about the time of the conference. Physicists from around the world will use the Relativistic Heavy Ion Collider to explore some of Nature's most basic -- and most intriguing -- ingredients and phenomena.

Scientific Program: The opening plenary session, chaired by Ilan Ben-Zvi of BNL, covered four highlights of the conference: Commissioning of B-Factories, commissioning results from RHIC, accelerators for cancer therapy and technology challenges of linear colliders. The first two asymmetric electron-positron B-Factory colliders were finished in the past year: PEP-II at SLAC in the USA and KEKB at KEK in Japan. These two accelerators use many novel accelerator advancements to allow high design luminosities, as reported by John Seeman of SLAC. Michael Harrison of BNL presented the progress on the commissioning and highlights of RHIC. Accelerators for cancer therapy, an area in which accelerators benefit society in a highly visible way, were presented by James Slater of Loma Linda University, who observed that designing the clinical accelerator requires a highly orchestrated design effort involving the entire facility. The last presentation of the Opening Plenary session, on the technology and challenges of linear colliders, was invited from Bjoern Wiik, the director of DESY. Four weeks before PAC'99, the world's scientific community learned about the tragic loss of this internationally acclaimed accelerator scientist, a compassionate colleague and an outstanding director of DESY. The chair of the session, John Peoples of Fermilab eulogized Bjoern. Then he introduced Reinhard Brinkmann of DESY, who rose to the challenge of reviewing the design challenges of a high energy, high luminosity e+e- linear collider in a very short time. Reinhard discussed various technical options and presented the status of the R&D effort underway at several laboratories.

Commissioning results were reported on the Fermilab main injector. Plans for major upgrades were presented such as a five-fold luminosity upgrade of HERA. The progress made in the acceleration of polarized protons to high energy at the AGS led to plans for polarized beams in RHIC and HERA. The Large Hadron Collider (LHC), the largest machine under construction, incorporates many technological innovations in order to achieve its design objectives at the lowest cost. Lower costs are also the main challenge for the Very Large Hadron Collider that is under initial consideration. Light source talks were evenly divided between storage ring results and Free-Electron Lasers. The storage ring talks included the performance of SPring 8 by Hiromichi Kamitsubo and a look into the future provided by Albin Wrulich. FEL presentations included the high power lasing results of the TJNAF FEL by Steve Benson and a look towards future x-ray FELs by Li Hua Yu.

Interesting advances were reported in all areas of accelerator technology. Self-bunching electron guns based on secondary emission have been developed at FM Technologies, Inc., and a pulsed photoinjector operating at GV/m field was reported by BNL. Very short period undulators were described using either a superconducting magnet (Karlsruhe) or microwave resonant structures (ANL). Ron Scanlan reported on superconducting accelerator magnet advances towards fields higher than 10T, including Nb3Al as well as the high temperature superconductors in both tape and cable configurations. Vincenzo Palmieri introduced the production of seamless niobium cavities, and many talks covered various technological aspects of very high current proton accelerators.

Accelerators are versatile tools for the production of various beams: protons, electrons, neutrons, x-rays, heavy ions, muons, neutrinos, and other secondary beams. These beams serve not just basic research in nuclear and high-energy physics, but also a multitude of applications: cancer therapy, neutron radiography, sterilization, production of isotopes, medicine, material science, contraband detection and much more. Gary Hogan described the use of protons for producing radiographic motion pictures of dense, exploding objects, and Jose Alonso talked about the Spallation Neutron Source (SNS).

The final plenary session offered a look to the future of the major uses of accelerators: William Marciano described the future of High Energy Physics, and Nathan Isgur that of Nuclear Physics. Wayne Hendrickson presented the impact of synchrotron radiation on structural biology, and Andrew Taylor the physics potential of MW class spallation sources.

In all, 1602 abstracts were submitted, for 79 invited and 120 contributed talks, and 1403 posters. In addition, a very successful 3-day industrial exhibition was held, featuring 40 exhibitors, and over thirty satellite topical and committee meetings were scheduled.

Social Program and Awards: The social program began on Sunday evening with a reception. The conference banquet was held in the Marriott Marquis Hotel on Tuesday evening and attended by 669 - a good number even in view of the culinary and cultural attractions of downtown New York! Following the conference, 187 participants attended a tour of Brookhaven National Laboratory on Saturday.

Awards were presented at the conference banquet. The APS Robert R. Wilson Prize was awarded to Robert Palmer, (BNL) for his many diverse contributions and innovations in particle accelerator and detector technologies.

Of the IEEE/PAC Technology Awards, the first went to Ilan Ben-Zvi (BNL) for contributions to high-brightness electron beams and superconducting rf and for leadership of BNL's Accelerator Test Facility. The second award went jointly to William Foster and Gerald Jackson, (FNAL) for the development of the first large-scale application of permanent magnet technology.

The US Particle Accelerator School Prizes were given to Robert Gluckstern, (UMD) for contributions to the understanding of fundamental processes in high-intensity beams and to Bruce Carlsten, (LANL) for the concept of emittance compensation.

The APS Award for Outstanding Doctoral Thesis Research went to Zhirong Huang (Stanford U) for his analysis of radiation damping and quantum excitation in novel accelerator configurations.

A large number of companions registered, about 310, owing no doubt to the attractions of New York City. Many companions and participants enjoyed the tours, theaters, shows and museum visits assisted by a week of good weather.

Proceedings: As at PAC'95 and PAC'97, electronic publication was the norm. The abstracts were collected on the web site together with author information that went to the conference database. Authors enjoyed the ability to edit the submitted abstracts and apply corrections (that somehow are always needed). The papers were sent by electronic means with few exceptions. Completed papers were placed on the PAC'99 web site as soon as they were processed, with the majority of the papers being on the web by the end of the conference. The proceedings are being published by IEEE in both book and CD-ROM form, and are also available on a combined PAC/EPAC/APAC Web sitehttp ( The number of CD-ROMs ordered was double that of books. Publication has been supported by generous grants from the US Department of Energy, National Science F oundation and Office of Naval Research.

Acknowledgements: Space is unfortunately too short to thank individually all those people whose dedicated efforts, often over a period of many months, were responsible for the success of the conference - especially the members of the Organizing Committee, Program Committee, Local Organizing Committee, and BNL staff. Exceptions must be made however for Mary Campbell, the Conference Secretary whose hand was everywhere, John Smith, the computer and electronic data group leader who made it all possible and Chris Ronick, the Hotel Coordinator who managed this enormous event calmly and confidently.

Bill Weng Ilan Ben-Zvi
Conference Chairman Program Chairman