Experimental evaluation of sub-sampling IQ detection for low-level RF control in particle accelerator systems

The low-level radio frequency (LLRF) control system is one of the fundamental parts of a particle accelerator, ensuring the stability of the electro-magnetic (EM) field inside the resonant cavities. It leverages on the precise measurement of the field by in-phase/quadrature (IQ) detection of an RF probe signal from the cavities, usually performed using analogue downconversion. This approach requires a local oscillator (LO) and is subject to hardware non-idealities like mixer nonlinearity and long-term temperature drifts. In this work, we experimentally evaluate IQ detection by direct sampling for the LLRF system of the Polish free electron laser (PolFEL) now under development at the National Centre for Nuclear Research (NCBJ) in Poland. We study the impact of the sampling scheme and of the clock phase noise for a 1.3-GHz input sub-sampled by a 400-MSa/s analogue-to-digital converter (ADC), estimating amplitude and phase stability below 0.01% and nearly 0.01◦, respectively. The results are in line with state-of-the-art implementations, and demonstrate the feasibility of direct sampling for GHz-range LLRF systems

Technical Design Report for the PANDA Solenoid and Dipole Spectrometer Magnets

This document is the Technical Design Report covering the two large spectrometer magnets of the PANDA detector set-up. It shows the conceptual design of the magnets and their anticipated performance. It precedes the tender and procurement of the magnets and, hence, is subject to possible modifications arising during this process.Comment: 10 pages, 14MB, accepted by FAIR STI in May 2009, editors: Inti Lehmann (chair), Andrea Bersani, Yuri Lobanov, Jost Luehning, Jerzy Smyrski, Technical Coordiantor: Lars Schmitt, Bernd Lewandowski (deputy), Spokespersons: Ulrich Wiedner, Paola Gianotti (deputy

Physics Performance Report for PANDA: Strong Interaction Studies with Antiprotons

To study fundamental questions of hadron and nuclear physics in interactions of antiprotons with nucleons and nuclei, the universal PANDA detector will be built. Gluonic excitations, the physics of strange and charm quarks and nucleon structure studies will be performed with unprecedented accuracy thereby allowing high-precision tests of the strong interaction. The proposed PANDA detector is a state-of-the art internal target detector at the HESR at FAIR allowing the detection and identification of neutral and charged particles generated within the relevant angular and energy range. This report presents a summary of the physics accessible at PANDA and what performance can be expected.Comment: 216 page

Technical Design Report for the: PANDA Micro Vertex Detector

This document illustrates the technical layout and the expected performance of the Micro Vertex Detector (MVD) of the PANDA experiment. The MVD will detect charged particles as close as possible to the interaction zone. Design criteria and the optimisation process as well as the technical solutions chosen are discussed and the results of this process are subjected to extensive Monte Carlo physics studies. The route towards realisation of the detector is outlined.Comment: 189 pages, 225 figures, 41 table

Digital post-distortion of an ADC analog front-end for gamma spectroscopy measurements

This work presents the experimental characterization and digital post-distortion (i.e., digital linearization) of a MHz-range ADC analog front-end for gamma radiation spectroscopy measurements. The front-end was firstly characterized by means of a conventional approach yielding Total Harmonic Distortion (THD) and Effective Number Of Bits (ENOB). Then, it was tested using \u3bcs-range pulsed excitations, which are the typical waveforms encountered in gamma spectroscopy. After applying digital post-distortion, the linearized receiver shows a THD reduced by more than 20 dB, a substantial improvement in ENOB, and a higher accuracy in the acquisition of pulsed waveforms

Development of uTCA Hardware for BAM system at FLASH and XFEL

This paper describes the design of a uTCA modular card system suited for conversion, sampling and processing of optical pulses. The system consists of a uTCA carrier card along with a double width FPGA Mezzanine Card (FMC) with a changeable optical frontend. The cards were designed for the needs of the BAM system of the FLASH and XFEL accelerators at the DESY facility in Hamburg. The carrier board contains a very powerful FPGA, all required uTCA circuits along with digital interfaces. The FMC card mainly contains four 16-bit fast Analog-to-digital converters (up to 250 MSPS), ADC clock generation and distribution modules, two SFP connectors and a specialized dual RS-485 connection. This paper describes such issues as system organization into universal digital circuits and specialized analog and clock circuits to allow high speed real-time analysis of the properties of thehigh-bandwidth optical signals of the BAM system and better control of the accelerator beam

Software layer for FPGA-based TESLA cavity control system (part 1)

The paper describes design and practical realization of software for laboratory purposes to control FPGA-based photonic and electronic equipment. There is presented a universal solution for all relevant devices with FPGA chips and gigabit optical links. The paper describes architecture of the software layers and program solutions of hardware communication based on Internal Interface (II) technology. Such a solution was used for superconducting Cavity Controller and Simulator (SIMCON) for the TESLA experiment in DESY (Hamburg). A number of practical examples of the software solutions for the SIMCON system were given in this paper