• A. Hofmann, I. Birkel, M. Fitterer, S. Hillenbrand, N. Hiller, E. Huttel, V. Judin, M. Klein, S. Marsching, A.-S. Müller, N.J. Smale, K.G. Sonnad, P.F. Tavares
  KIT, Karlsruhe

A new 90 kV e-gun had been installed at the 50 MeV microtron at ANKA. The emittance of the gun has been measured in long pulse mode (1 us, 200 mA) with a pepper-pot, resulting in 5 u.rad RMS normalised emittance. The single pulse width is less than 1 ns, resulting in a bunch purity in the storage ring of better 0.5 %. The old timing system for gun and injection elements based on 4 Stanford delay generator has now been replaced by an event driven system from Micro-Research Finland (MRF). This consists of one event generator and one event receiver. Visualisation and programming is achieved with PVSS from ETM Austria. The e-gun trigger can be adjusted in 10 ps steps. The entire system is phase locked to the 499.69 MHz RF signal.

• P.F. Tavares
  Karlsruhe Institute of Technology (KIT), Karlsruhe
• M. Fitterer, N. Hiller, A. Hofmann, V. Judin, M. Klein, S. Marsching, N.J. Smale, K.G. Sonnad
  KIT, Karlsruhe
• E. Huttel, A.-S. Müller
  FZK, Karlsruhe
• P.F. Tavares
  LNLS, Campinas

We present results of a series of measurements aimed at characterizing the beam coupling impedances in the ANKA electron storage ring. The measurements include transverse coherent tune shifts, bunch lengthening and synchronous phase shift as a function of single bunch current. These were performed under a variety of conditions in the ANKA ring, including injection energy (500 MeV), nominal operating energy (2.5 GeV) as well as at 1.3 GeV and in the low alpha mode and are part of a longer term effort to understand the ANKA impedance over a wide frequency range.

• S. Hillenbrand, M. Fitterer, N. Hiller, A. Hofmann, E. Huttel, V. Judin, M. Klein, S. Marsching, A.-S. Müller, K.G. Sonnad, P.F. Tavares
  KIT, Karlsruhe

The Karlsruhe Institute of Technology (KIT) proposes to build a new light source called TBONE (THz Beam Optics for New Experiments), which aims at a spectral range from 0.1 to 150 THz with a peak power of several MW and a pulse length of only 5 fs. In order to achieve this, a beam transport system with minimal losses and a high bunch compression is required. In this paper we present first beam dynamic simulations of the superconducting linac as well as the bunch compressor and give a short status report of the TBONE project.

• N. Hiller, S. Hillenbrand, A. Hofmann, E. Huttel, V. Judin, B. Kehrer, M. Klein, S. Marsching, A.-S. Müller, A. Plech, N.J. Smale, K.G. Sonnad, P.F. Tavares
  KIT, Karlsruhe

A dedicated optics with a low momentum compaction factor is used at the ANKA storage ring to reduce the bunch length to generate coherent synchrotron radiation (CSR). A double sweep streak camera is employed to determine the bunch length and shape for different optics and as a function of the beam current. Measurements of the longitudinal bunch profile have been performed for many different momentum compaction factors and various bunch currents. This paper describes the set up of the streak camera experiments and compares the measured bunch lengths to theoretical expectations.

• V. Judin, S. Hillenbrand, N. Hiller, A. Hofmann, E. Huttel, M. Klein, S. Marsching, A.-S. Müller, N.J. Smale, K.G. Sonnad, P.F. Tavares
  KIT, Karlsruhe
• H.W. Huebers
  Technische Universität Berlin, Berlin
• A. Semenov
  DLR, Berlin

Since a few years CSR-Radiation created in low alpha mode is provided by the ANKA light source of the KIT*. Depending on the bunch current, the radiation is emitted in bursts of high intensity. These bursts display a time evolution which can be observed only on long time scales with respect to the revolution period. The intensity of the emitted radiation during a burst is significantly increased w.r.t. steady state emission. Some users of the THz radiation don't require particularly constant emission characteristics and could profit from the higher intensity. A better understanding of the long term behaviour of those bursts could help to improve the conditions for those users. We have investigated THz radiation in multiturn mode with a hot electron bolometer. Its time response of 165ps allowed us to resolve the signals of individual bunches. Using a 6GHz LeCroy oscilloscope for data acquisition, we were able to save up to 1.6ms long signal sequences at a sampling rate of 20GS/s. This amount of data corresponds to over 4000 bunch revolutions and allows turn-by-turn signal tracking of desired bunches. In single bunch mode we are able to take segmented data to avoid a huge overhead.

* KIT - Karlsruhe Institute for Technology

• A.-S. Müller, I. Birkel, M. Fitterer, S. Hillenbrand, N. Hiller, A. Hofmann, E. Huttel, K.S. Ilin, V. Judin, M. Klein, S. Marsching, Y.-L. Mathis, P. Rieger, M. Siegel, N.J. Smale, K.G. Sonnad, P.F. Tavares
  KIT, Karlsruhe
• H.W. Huebers
  Technische Universität Berlin, Berlin
• A. Semenov
  DLR, Berlin

In synchrotron radiation sources coherent radiation is emitted when the bunch length is comparable to or shorter than the wavelength of the emitted radiation. At the ANKA storage ring this radiation is observed as so-called edge radiation (emitted in the fringe field of a bending magnet). This radiation exhibits a radial polarisation pattern. The observed pattern, however, is influenced by the radiation transport in the beam line. A detector system based on a superconducting NbN ultra-fast bolometer with an intrinsic response time of about 100 ps as well as conventional Si bolometers were used to study the beam polarisaion. This paper reports the observations made during measurements.