1. THE MAFF IH-RFQ TEST STAND AT THE IAP FRANKFURT A. Bechtold, J. Fischbach, D. Habs, O. Kester, M. Pasini, U. Ratzinger, J. Rehberg, M. Reichwein, A. Schempp, T. Sieber et al. LMU München IH-type structures are one of the most promising developments in the range of linear accelerating RF structures of the last years. They are widely used with drift tubes and are known to provide a very high reliability at a comparatively moderate power consumption. Furthermore the thermal power dissipation is distributed on the individual components (tank, stems, tubes etc.) advantageously. This IH-resonator concept is now applied to RFQ structures for the second time with the MAFF-RFQ and can now be compared to a very similar 4-rod type structure integrated at the CERN REX-ISOLDE setup for the first time. Main parameters of both machines are listed on the right. We are now planning to do some performance tests with a He + beam at the IAP. The RFQ is mounted to the frame, first RF tests at low power have already been done, the Ion source and the injection system are currently under construction. The main goal of these investigations is to prove the predicted advantages of this resonator type applied to RFQ accelerators especially in comparison to 4-rod structures. This will be done with special respect to a continuous wave (c.w.) operation, which is desired for the EURISOL post accelerator, where power dissipation and cooling is a very important aspect. The MAFF IH-RFQ completed on the frame Assembly of one of seven the IH modules Here you see the different work procedures with the installation of the 40 cm long electrode segments into the IH-modules that were manufactured at NTG as well as the electrodes. The four electrodes of each segment are supported by 5 rings. These rings are wedged on top of the stems by semi-rings. The cylindrical channel formed by the stems on axis of each module was milled in one final working process during fabrication to guarantee the precision that is required in that area where the electrodes are mounted. Both processes assembling the electrode segments and installation of these segments into the IH- module have been done by means of special templates to bring the electrodes into axial position with an accuracy better that 30 µm in all three dimensions. A possible normal conducting RFQ solution for the proposed EURISOL post accelerator A combination of three superconducting RFQs has been proposed for the EURISOL post accelerator layout. At least one of this triplet could be replaced by a normal conducting device. A preliminary Electrode design has been prepared for presentation here. We have chosen a quite gentle electrode voltage of 60 kV, which leads (a) to a comparatively low power consumption of only 82 kW, gives (b) some space to go to higher electrode voltages for charge to mass ratios higher than 9.52 and (c) reduces the thermal losses, which have to be cooled by an advanced cooling system at c.w. operation. The current resonance frequency of the post accelerator is 88 MHz, not 80 MHz like it was proposed in the first place. The transmission of our design proposal is 100% at zero current and is still 97.2% for the highest expected current of 7.5 mA. In Frankfurt we have gained several experiences with c.w. 4-rod RFQs most recently with a 4 m long structure for Deuterons at 176 MHz for acceleration up to 1.5 MeV/u. There is a clear cooling concept for that kind of machines but we would still have to do some investigations on an appropriate concept for the IH-type structure. Especially the electrodes are a critical case. They are always cooled at high duty cycle 4-rod structures but probably would not have to be cooled with the IH-type structure as the expected power dissipation on the electrodes is here expected to be only 5%. Proposed set up of the post acceleratorThe RFQ electrode design. Plotted are aperture, modulation, ideal phase and phase advances against cell number. Dynamic simulations with an input distribution of 0.5  mm mrad emittance on the left, the beam evolution along the structure in the middle and the output on the right. URL: http://iaprfq.physik.uni-frankfurt.de e-mail: a.bechtold@iap.uni-frankfurt.de Low Power RF-Measurements One of the main aspects with the IH-type structure is the expected low power consumption resp. a high quality factor Q and also a high shunt impedance (Rp-value). To give an idea of what the power consumption of the IH-RFQ in total will be, we have done some preliminary RF-measurements on a single module and compared them to appropriate Microwave Studio simulations done for both, the single module and the whole thing. The results are summarized in table below. The deviations between simulation and measurement regarding the Rp- and Q-value are well known and due to (a) the idealized perfect conductivity between different parts and (b) the finite grid resolution, which had been chosen to be the same in both cases for comparability although the single module could have been calculated with a finer resolution. The deviations regarding the frequency are mainly related to the neglected electrode modulation, which can not be taken under consideration with the simulations because of data overflow. During operation the frequency can be tuned and adjusted to the design value by a so called “plunger”.