[en] The Mainz Microtron (MAMI) will consist of three cascaded Race-Track-Microtrons with a Van De Graaff as injector. The first stage, delivering an output energy of 14 MeV, has been working for about two years in the Institut fuer Kernphysik in Mainz. The second stage is presently under construction and will increase the output-energy to 180 MeV. A principal problem with these microtrons is the precise positioning of each individual turn to the middle-axis of the accelerating rf-section. Therefore in front of and behind the section monitors for detecting the beam-position in each of the 20 turns of the first stage has been installed. A computer reads out this data and determines the setting of the 80 steering coils in the return-tracks of the beam (two coils in horizontal and vertical direction for each turn). The report describes the details of the hard- and software of this system

[en] This paper reports on the actual transverse beam optics of the second stage of the Mainz Microtron determined by adjusting the parameters of a first order computer model thus, that the model described the behavior of the beam (betatron-like oscillations). The method is useful for uncovering misalignments and wrong tuning of magnetic components of a beam transport system. Several optical defects in the microtron could be tracked down and corrected. Also nonlinear perturbations were measured in this way. Including a fit-algorithm the adapted model has subsequently been used for computer-controlled transverse matching to the microtron. From a synchrotron-radiation monitor a beam mismatch is detected and can be corrected by automatic adjustment of the injecting interface. Both methods can be generalized to other beam transport systems

[en] MAMI (Mainz Microtron) is an electron accelerator consisting of a cascade of three race-track microtrons, with an output electron beam of 855 MeV and 100 μA cw. The first two stages (output energy 180 MeV) were operative for nuclear-physics experiments from 1983 to 1987 and have since been transferred to a new building. They will serve as an injector for the third stage, now under construction. The control system for MAMI was based on a versatile process communication software system for a network of processors with multiprocess operating systems. This system has previously proved very successful, so we decided to rely on it as control system for the new, upgraded accelerator, replacing the control computers (instead of two HP1000s, now one MicroVAX-II) and making several changes and extensions. We strictly unified the communication interface to the processes. Accordingly, a set of display, steering, measuring and optimization processes can be used in a flexible manner: for example, emittance measurements at several points of the beam line and automatic beam-position optimization in the beam line and in the microtrons. Using a portable compiler generator, we were able to develop a BASIC-like interpreter for high-level control purposes in a very short time (one man-month). In addition to the MicroVAX we are planning to operate other processors as well (VME and single-board computers), coupled via Ethernet, using our communication software. (orig.)

[en] The Mainz microtron (MAMI) is a cw electron accelerator consisting of three cascaded racetrack microtrons with a 3.5 MeV linac as injector. The microtron is in heavy demand for a wide variety of applications and is often run by less skilled operators. A reliable and redundant beam monitoring system is necessary. RF cavities are used to determine the intensity, phase and center position of the bunched beam. Two types of ferrite current monitors are used, one as a protective transparency monitory at a dozen points along the beamline, and the other to measure the absolute cw beam current. For a diagnostic of the transverse beam matching and possible phase space distortions and couplings the synchrotron radiation is observed. Wire scanners are installed at forty points in MAMI to determine the beam center position and give a cut through the beam profile. The quadrupoles on the interface beamlines are used together with a scanner downstream for transverse emittance measurement. Backward transition radiation may be observed using polished aluminum sheets put at 45 degrees into the beam. Ionization chambers are used to detect beam losses. 5 figs., 8 refs., tab

[en] This paper reports on a cw electron accelerator, consisting of two cascaded race track microtrons (14 and 180 MeV) with a Van de Graaff preaccelerator, taken into operation in March 1983. From the beginning the machine was relatively easy to operate and ran stable over many hours with a very good beam quality. The transverse beam emittance turned out to be slightly increased to about 0.014 π mm mrad at 183 MeV mainly due to geometrical and chromatic aberrations, whereas the measured energy spread of about 30 keV FWHM corresponded to the design value. Most of the technical problems were caused by the Van de Graaff preaccelerator and by its sensitivity to γ-radiation, which limited the maximum beam current to abut 65 μA at full energy. In the period from 1983 to 1987 MAMI A has been operated for 18,670 hours altogether and 17,160 hours for experiments in nuclear physics. Only 17% of this time were used for accelerator tuning and for the repair of acute failures

No abstract available

[en] The 855 MeV cw-electron-accelerator MAMI (MAinz MIkrotron) has been working for 18 months for intermediate-energy nuclear physics coincidence experiments. The racetrack microtron (RTM) consists of a 3.5 MeV injector linac and three cascaded RTM's for 14, 180 and 855 MeV, respectively. The main experiences with this rather complicated machine are reported. (R.P.) 6 refs.; 2 figs

[en] A source of polarized electrons based on a helium flowing afterglow has been developed at Orsay. This source, SELPO-M, has been placed on a 100 kV platform and set up in such a way as to allow its connection to the MAMI accelerator. Its performances in terms of current, polarization and optical properties are given. Its figure of merit (IP²≅75 μA) appears highly competitive as compared to strained GaAs sources. (author)

[en] MAMI (Mainz Microtron), is a c.w. electron accelerator consisting of a cascade of three racetrack microtrons with an output electron beam of 855 MeV and 100 μA, is controlled by a network of computers. A new operator interface using workstations has been developed. This interface enables the operator to control the machine and display graphically the actual status of the accelerator components and systems. The graphic images were developed using a commercial graphics package. Operator actions are performed in the usual way by sending messages to the processes controlling the devices and status display is provided by using the alert feature of the MAMI run-time database. The global status of systems consisting of several components, is computed by a program generated from a logical dependency description in symbolic notation, via a C-code generator. ((orig.))

[en] The polarized electron source at the Mainz microtron has improved its performance in every parameter during the last year. Run times have been performed with simultaneously 20 Mikroamps of beam current and more than 80% of polarization. We demonstrate that the limited beam-current lifetime product is due to a transmission loss of about several 10^-4. The loss can be minimized by the usage of photocathodes with only partially photosensitive surface, thus resulting in a nearly one order of magnitude higher beam-current lifetime product