FLAIR - the "Facility for low-energy Antiproton and Ion Research" has not been part of the original CDR of the FAIR facility. The FLAIR collaboration suggests to exploit the high antiproton flux of FAIR to provide stored as well as fast and slow extracted`p between 30 MeV and 20 keV, and cooled`p at rest or ultra-low eV energy, i.e. to provide antiproton beams of unprecedented qualities, energies, and intensities. The rich physics program comprises precision measurements of properties of the antiproton as well as precision spectroscopy of antiprotonic atoms and antihydrogen for tests of CPT and other fundamental symmetries and interactions, interaction of matter with antimatter, and the use of slow`p as a hadronic probe for nuclear structure studies.

The AD facility at CERN succeding LEAR (the first generation low-energy antiproton facility) is presently the only place to provide a low energy antiproton beam. However, (i) its energy (5 MeV) is still too high for efficient trapping, (ii) the`p intensity is low, and (iii) only pulsed beams are available. Moreover, the future of the AD after 2005 is not clear. The PAC therefore considers FLAIR with its considerably improved`p beam properties to be a unique second generation low-energy antiproton facility with exciting new experimental possibilities, taking also advantage of synergies with the low-energy HCI projects of the SPARC community such as the HITRAP, being incorporated now in FLAIR and being the ideal instrument e.g. for a precision determination of the magnetic moment of`p.

The FLAIR facility requires`p decelerated in the NESR down to 30 MeV. This option was not included in the CDR, but the NESR design group has studied it and considers it to be doable. To further decelerate the antiprotons, the FLAIR facility suggests to use CRYRING to bridge the gap between 30 MeV and 0.3 MeV, and an electrostatic ring (USR) for further deceleration to 20 keV. The PAC considers the reuse of CRYRING with is electron cooler and its own ion source to be a proper and important contribution to FLAIR and a comparably cheep solution as well. The PAC therefore likes to urge the STI to help in the negotiations with Sweden to keep CRYRING in an operational state until it can be transferred to GSI; an early availability of the FLAIR building should be envisaged.The electrostatic USR ring needs considerable R&D as the deceleration of ions in an electrostatic ring has never be done and the electron cooler has to work at a very low energy; the MPI for nuclear physics is prepared to take over the responsibility for this development. The addition of a positron storage ring in a merging beam arrangement with the USR is presently only an option.

The proposed experiments with`p and radioactive nuclei to determine neutron and proton radii would require a separate beam line e.g. from the low energy cave of the Super FRS to the FLAIR facility to supply the low energy radioactive ions. The feasibility of this or other options should be investigated, however, before being regarded as a future option, the NUSTAR- and APPA-PAC should discuss together also the virtue of these experiments as compared to other techniques.

The medical applications of`p at FLAIR are not considered to be a serious option given the complexity of producing antiprotons.

Summary: The FLAIR facility will open up worldwide new and unique possibilities for fundamental research with low energy antiprotons. The FLAIR collaboration, which includes most of the groups presently involved in the antiproton research at the AD, is highly competent and committed. The PAC therefore strongly recommends to accept the basic FLAIR proposal and to encourage the collaboration to work - in close contact with the SPARC community - towards a Technical Report, including detailed working packages, time schedules and milestones, manpower and cost estimates, and to continue defining the responsibilities within the collaborations for the R&D and construction phase and with respect to the costs.

Evaluation Result of FLAIR LOI, July 5, 2004

Dear Professor Widmann,

Your Letter of Intent "FLAIR- A Facility for Low-energy Antiproton and Ion Research" has been positively evaluated by the APPA-PAC (see report attached) and recommended for getting green light to go towards a Technical Proposal. We concur with this evaluation and invite you to present a Technical Proposal at the latest 15th of January 2005, where your collaboration responds to the best of its possibilities to the points raised in the PAC report and to the topics outlined in the attached template. In your document we ask you to follow closely this outline and leave free the points, which are not applicable to your experiment. This will allow an easier evaluation of the proposals, which will be done by the end of March 2005.

For any question related to the evaluation of the proposal and the physics issues during this time period do not hesitate to contact the chairman of your PAC. For technical matter related to the facility and the implementation of your experiment during this time please do not hesitate to contact Hans Gutbrod.

Looking forward to your further collaboration

with best regards

Sidney Gales                                  Hans H. Gutbrod

Chairman of STI                            FAIR project coordinator