THE IASA RACETRACK MICROTRON FACILITY, A PROGRESS REPORT E. Stiliaris, H. Avramopoulos, D. Baltadoros, M. Barbarosou, S. Cohen, D. Economou, T.A. Filippas, E.N. Gazis, A. Karabarbounis, M. Malagari, D. Maroulis, N.H. Papadakis, C.N. Papanicolas, N. Patavalis, P. Phinou, H. Rahmani, N. Sparveris, N. Uzunoglou, N. Vodinas Institute of Accelerating Systems and Applications, P.O.Box 17214, GR–10024 Athens, Greece and H. Herminghaus * , Inst. f. Kernphysik, Univ. Mainz, Germany Abstract The Institute of Accelerating Systems and Applications (IASA) is pursuing research and facilitates postgraduate studies in traditional and cross-disciplinary areas where ac- celerators play an important role. The first major facility of IASA, now under construction, is a 242 MeV two-stage CW cascade microtron. During the ongoing period of civil construction a staging area has been set up for the instal- lation of the injector and the testing of several key subsys- tems. A progress report on this project is presented here. 1 INTRODUCTION The first large scale facility of IASA is a 242 MeV microtron[1]. It is being constructed largely out of the components of the NBS/LANL CW RaceTrack Microtron (RTM) [2] supplemented by those of the University of Illi- nois R&D RTM project[3]. The available equipment from the above two projects combined with the additional equip- ment produced by IASA in the last two years, allows a design based on a cascade (two stage) RTM. The accel- erator comprises of a 6.5 MeV injector and two cascaded RTMs (RTM1 and RTM2) with output energies 41 MeV and 242 MeV respectively (Fig. 1). Two interfacing sections match the output of the injector to the acceptance of RTM1 and the output of the latter to the acceptance of RTM2. They also serve to transport the beam to experimental areas. Both RTMs are designed for variable energy extraction[4][5]. The main characteristics of the machine are summarized in Table 1. INJ RTM1 RTM2 Injection Energy [MeV] 6.5 41 Gain per Turn [MeV] 1.32 8.04 Number of Recirculations 26 25 Max Output Energy [MeV] 6.5 41 242 Max Current [μA] 600 100 100 Frequency [MHz] 2380 2380 2380 Incremental Number ν 1 1 Magnets Field [T] 0.2196 1.338 RF Power Consum. [KW] 118.7 29.0 169.3 Spacing [m] 8.8 3.25 8.7 Table 1: The main characteristics of the IASA Cascade RaceTrack Microtron * Supported by the EU, TMR-Programme ERBFMBICT961234 Figure 1: Layout of the planned IASA CW cascade (two- stage) microtron. The accelerator vaults and experimental areas are shown. 2 DESIGN AND OPTICS CALCULATIONS The design philosophy is such as to result in stable oper- ation, simple tuning and optimal use of the available linac sections, RF equipment and End-Magnets. The injector consists of a 100 keV electron gun, a chop- ping and bunching system, a capture section, a preacceler- ator and a booster. This design increases the initial NIST injector energy of 5 MeV to 6.5 MeV. Its optics has ex- tensively been studied with the code PARMELA[6]. Most favorably, it turned out that the injector can be tuned such as to match RTM1 longitudinally without any further mea- sures. This is demonstrated in Fig. 2[7]. Both microtron stages use quadrupole doublets on ei- ther side of the linac for transverse focusing, and both use the MAMI schemes[8] for injection and extraction, respec- tively. For RTM1, it was possible to apply a variant of this extraction scheme which provides achromatic extrac- tion directly[9]. The first microtron (RTM1) is designed to operate with an asymptotic synchronous phase of 18 deg. The choice of that particular phase is made on the basis of keeping the longitudinal acceptance of RTM1 sufficiently high while relaxing the need of an extremely demanding control of the RF stability and injector output energy. The accelerating 1042 0-7803-4376-X/98/$10.00  1998 IEEE