Electrodynamic, Albuquerque, New Mexico, USA
ODU, Norfolk, Virginia, USA
JLab, Newport News, Virginia, USA
RF cavities have been designed and constructed that simultaneously and exclusively resonate many harmonic TMono modes. These modes are axially symmetric and have their electric field maximum along the cavities bore. A periodic beam passing through a harmonic cavities bore excites these modes whose superposition can be measured at the cavities antenna with a sampling oscilloscope. Processing the detected waveform with the harmonic cavities transfer function yields the Fourier series of the beam, and a near real-time, non-invasive measurement of the beams longitudinal bunch shape and duration. Experiments have been performed on the 130 kV injector at the Thomas Jefferson National Accelerator Facilities Continuous Electron Beam Accelerator Facility. The harmonic cavities sensitivity was near 1 mV/μA and measured beam bunches ranging in width from 45 to 150 picoseconds (FWHM). These measurements were in close agreement with measurements made using an invasive bunch measurement system as well as predictions by a particle tracking simulations.
CERN, Geneva, Switzerland
INFN-Roma, Roma, Italy
INFN/LNF, Frascati (Roma), Italy
The DAΦNE Beam Test Facility (BTF) is operational in Frascati since 2003. In the last years the beam diagnostics tools have been completely renewed and the services for users have been largely improved. We describe here the new transverse beam diagnostics based on new GEM TPC detectors and MEDIPIX Silicon pixel detectors, the renewed DAQ system and the data caching system based on MEMCACHED and the integration of the new sub-systems in the new data-logging. Results on the optimization of the transverse beam spot and divergence are reported as well as the real-time diagnostics and feedback user experience.
KIT, Eggenstein-Leopoldshafen, Germany
DESY, Hamburg, Germany
PSI, Villigen PSI, Switzerland
TUL-DMCS, Łódź, Poland
The acquisition rate of commercially available line array detectors is a bottleneck for beam diagnostics at high-repetition rate machines like synchrotron lightsources or FELs with a quasi-continuous or macro-pulse operation. In order to remove this bottleneck we have developed KALYPSO, an ultra-fast linear array detector operating at a frame-rate of up to 2.7 Mfps. The KALYPSO detector mounts InGaAs or Si linear array sensors to measure radiation in the near-infrared or visible spectrum. The FPGA-based read-out card can be connected to an external data acquisition system through a high-performance PCI-Express 3.0 data-link, allowing continuous data taking and real-time data analysis. The detector is fully synchronized with the timing system of the accelerator and other diagnostic instruments. The detector is currently installed at several accelerators: ANKA, the European XFEL and TELBE. We present the detector and the results obtained with Electro-Optical Spectral Decoding (EOSD) setups.
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
CERN, Geneva, Switzerland
Electro-Optic Transposition (EOT) is the basis for an improved longitudinal bunch profile diagnostic we are developing in ASTeC as part of the CLIC UK research program. The scheme consists of transposing the Cou-lomb field profile of an electron bunch into the intensity envelope of an optical pulse via the mixing processes that occur between a CW laser probe and Coulomb field in an electro-optic material. This transposed optical pulse can then be amplified and characterised using robust laser techniques ' in this case chirped pulse optical parametric amplification and frequency resolved optical gating, allowing the Coulomb field to be recovered. EOT is an improvement over existing techniques in terms of the achievable resolution which is limited by the EO material response itself, reduced complexity of the laser system required since nanosecond rather than femtosecond lasers are used, and insensitivity of the system to bunch-laser arrival time jitter due to using a nanosecond long probe. We present results showing the retrieval of a THz pulse (Coulomb field stand-in) which confirms the principle behind the EOT system.
IAP/RAS, Nizhny Novgorod, Russia
Euclid TechLabs, LLC, Solon, Ohio, USA
UNN, Nizhny Novgorod, Russia
We propose a non-invasive bunch length measurement system based on RF pickup interferometry. A device performs interferometry between two broadband wake signals generated by a single short particle bunch. The mentioned wakes are excited by two consequent small gaps in beam channel. A field pattern formed by interference of the mentioned two coherent wake signals is registered by means of detector arrays placed at outer side of beam channel. The detectors are assumed to be low-cost integrating detectors (pyro-detectors or bolometers) so that integration time is assumed to be much bigger than bunch length. Because RF signals come from gaps to any detector with different time delays which depend on particular detector coordinate, the array allows to substitute measurements in time by measurements in space. Simulations with a 1 ps beam and a set of two 200 micron wide vacuum breaks separated by 0.5 mm were done using CST Particle Studio. These simulations show good accuracy. Moreover, one can recover the detailed temporal structure of the measured pulse using a new developed synthesis procedure.
