Caselle M., Brosi M., Chilingaryan S., Dritschler T., Hiller N., Judin V., Kopmann A., Muller A.-S., Raasch J., Rota L., Petzold L., Smale N.J., Steinmann J.L., Vogelgesang M., Wuensch S., Siegel M., Weber M.

in International Beam Instrumentation Conference, IBIC 2014 (2014).

Abstract

The ANKA storage ring generates brilliant coherent synchrotron radiation (CSR) in the THz range due to a dedicated low-ac-optics with reduced bunch length. At higher electron currents the radiation is not stable but is emitted in powerful bursts caused by micro-bunching instabilities. This intense THz radiation is very attractive for users. However, the experimental conditions cannot be easily reproduced due to those power fluctuations. To study the bursting CSR in multi-bunch operation an ultra- fast and high-accuracy data acquisition system for recording of individual ultra-short coherent pulses has been developed. The Karlsruhe Pulse Taking Ultra-fast Readout Electronics (KAPTURE) is able to monitor all buckets turn-by-turn in streaming mode. KAPTURE provides real-time sampling of the pulse with a minimum sampling time of 3 ps and a total time jitter of less than 1.7 ps. The KAPTURE system, the synchrotron operation modes and beam test results are presented in this paper.

Caselle M., Brosi M., Chilingaryan S., Dritschler T., Hertle E., Judin V., Kopmann A., Muller A.-S., Raasch J., Schleicher M., Smale N.J., Steinmann J., Vogelgesang M., Wuensch S., Siegel M., Weber M.

in IPAC 2014: Proceedings of the 5th International Particle Accelerator Conference (2014) 3497-3499.

Abstract

Copyright © 2014 CC-BY-3.0 and by the respective authors.The commissioning of a new real-time and high-accuracy data acquisition system suitable for recording individual ultra-short coherent pulses detected by fast terahertz detectors will be presented. The Karlsruhe Pulse Taking Ultra-fast Readout Electronics (KAPTURE) is able to monitor turn-by-turn all buckets in streaming mode. KAPTURE is based on a direct sampling pulse operating with a minimum sampling time of 3 ps and a total time jitter less than 1.7 ps. A very low noise layout design combined with wide dynamic range and bandwidth of the analog front-end enables the sampling of signals generated by different GHz/THz detectors. The system has already been used with NbN and YBCO superconductor film detectors as well as zero biased Schottky diode detectors. The digitized data is transmitted to a DAQ system by a FPGA high throughput board with data transfer rates of 4 GByte/s. The setup is accomplished by a real-time data processing unit based on high-end graphics processor units (GPUs) for on-line analysis of the frequency behaviour of the coherent synchrotron emission. The system has been successfully used to study the beam properties of the ANKA synchrotron radiation source located at the Karlsruhe Institute of Technology.