A 1 GHz RF Trigger Unit implemented in FPGA logic

Applications of Trigger Units (TU) can be found in almost all accelerators at CERN. The requirements in terms of operating frequencies, configuration or modes of operation change from one application to another, how-ever, in terms of design requirements for the Trigger Unit, the operating frequency is probably the most demanding one. In this work, we present an implementation of a Trigger Unit almost fully embedded in the FPGA logic operating at a maximum frequency of 1 GHz using the internal serializer/deserializer circuitry to simplify the timing constraints of the design. This implementation allows easy reconfiguration of the module and the development of new modes of operation, which are described in this paper.Comment: Poster presented at LLRF Workshop 2017 (LLRF2017, arXiv:1803.07677

LHC One-Turn Delay Feedback Commissioning

The LHC One-Turn delay FeedBack (OTFB) is an FPGA based feedback system part of the LHC cavity controller, which produces gain only around the revolution frequency (frev = 11.245 kHz) harmonics. As such, it helps reduce the transient beam loading and effective cavity impedance. Consequently, it increases the stability margin for Longitudinal Coupled Bunch Instabilities driven by the cavity impedance at the fundamental and allows reliable operation at higher beam currents. The OTFB was commissioned on all sixteen cavities in mid-October 2011 and has been used in operation since. The commissioning procedure and algorithms for setting-up are presented. The resulting improvements in transient beam loading, beam stability, and required klystron power are analyzed. The commissioning of the OTFB reduced the cavity voltage phase modulation from approximately six degrees peak-to-peak to below one degree at 400 MHz with nominal bunch intensity of 1.1e11 protons

RF Issues and Developments at the LHC Machine

The main RF system of the LHC, which uses 400MHz superconducting cavities, will be used to capture, accelerate and store the injected beam. A separate transverse damper system using electrostatic deflectors will be used to damp transverse oscillations. The associated low-level RF (LLRF) equipment is responsible for fast control of the accelerating voltage and phase in the cavities, the phase and radial position of the beam, and the synchronization of beam transfers between SPS and LHC. The LLRF system combines highfrequency analogue components with digital signal processing using FPGAs and DSPs. The extensive use of digital technology allows not only to achieve the required performance and stability but also to provide full remote control and diagnostics facilities needed in a machine where most of the RF system is inaccessible during operation

Samenvatting Monitoring Nulsituatie-Rapport Resultaten meetronde 2005-2006

Eind 2004 is door het Hoofdproductschap Akkerbouw (HPA), het Productschap Tuinbouw (PT) en LTO Nederland het initiatief genomen om de aaltjesproblemen gezamenlijk aan te pakken. Hiervoor is het actieplan aaltjesbeheersing gelanceerd. Eén van de projecten binnen dit actieplan was het monitoren van de nulsituatie. Dit project is uitgevoerd door een consortium van Blgg BV, NAK AGRO BV, en PPO-AGV. Binnen het project zijn tussen 2005 en 2006 425 akkerbouwbedrijven grondmonsters genomen. Deze zijn geanalyseerd op de meest bekende plantenparasitaire aaltjes. Daarnaast is aan de deelnemers gevraagd mee te werken aan een enquête over hun bedrijfsvoering en hun ervaringen met aaltje

Studies of RF Noise Induced Bunch Lengthening at the LHC

Radio Frequency noise induced bunch lengthening can strongly affect the Large Hadron Collider performance through luminosity reduction, particle loss, and other effects. Models and theoretical formalisms demonstrating the dependence of the LHC longitudinal bunch length on the RF station noise spectral content have been presented*,**. Initial measurements validated these studies and determined the performance limiting RF components. For the existing LHC LLRF implementation the bunch length increases with a rate of 1 mm/hr, which is higher than the intrabeam scattering diffusion and leads to a 27% bunch length increase over a 20 hour store. This work presents measurements from the LHC that better quantify the relationship between the RF noise and longitudinal emittance blowup. Noise was injected at specific frequency bands and with varying amplitudes at the LHC accelerating cavities. The experiments presented in this paper confirmed the predicted effects on the LHC bunch length due to both the noise around the synchrotron frequency resonance and the noise in other frequency bands aliased down to the synchrotron frequency by the periodic beam sampling of the accelerating voltage

Commissioning and performance of a phase-compensated optical link for the AWAKE experiment at CERN

In this work, we analyze the performance of the solution adopted for the compensation of the phase drift of a 3 km optical fiber link used for the AWAKE experiment at CERN. The link is devoted to transmit the reference signals used to synchronize the SPS beam with the experiment to have a fixed phase relation, regardless of the external conditions of the electronics and the link itself. The system has been operating for more than a year without observed drift in the beam phases. Specific measurements have proven that the jitter introduced by the system is lower than 0.6 ps and the maximum phase drift of the link is at the picosecond level.Comment: Poster presented at LLRF Workshop 2017 (LLRF2017, arXiv:1803.07677

Gewasbescherming in goede aarde : Terugblik op de KNPV-najaarsbijeenkomst, 8 december 2010, Wageningen

De KNPV-najaarsbijeenkomst op 8 december, had dit jaar als onderwerp ‘De Bodem’. Het programma is samengesteld in samenwerking met de Werkgroep Bodempathogenen en bodemmicrobiologie. De dag was tevens ook de najaarbijeenkomst van deze KNPV-werkgroep. Een recordaantal van 125 deelnemers, enthousiast publiek, gezelligheid, netwerken, een afwisselend programma, en inspirerende sprekers, maakten de dag tot een overdonderend succes

Digital Design Of The LHC Low Level rf: The Tuning System For The Superconducting Cavities

The low level RF systems for the LHC are based extensively on digital technology, not only to achieve the required performance and stability but also to provide full remote control and diagnostics facilities needed since most of the RF system is inaccessible during operation. The hardware is based on modular VME with a specially designed P2 backplane for timing distribution, fast data interchange and low noise linear power supplies. Extensive design re-use and the use of graphic FPGA design tools have streamlined the design process. A milestone was the test of the tuning system for the superconducting cavities. The tuning control module is based on a 2M gate FPGA with on-board DSP. Its design and functionality are described, including features such as automatic cavity measurements. Work is ongoing on completion of other modules and building up complete software and diagnostics facilities

The association of childhood maltreatment with depression and anxiety is not moderated by the oxytocin receptor gene

Background: The oxytocin receptor (OXTR) gene may be involved in resilience or vulnerability towards stress, and hence in the development of stress-related disorders. There are indications that OXTR single nucleotide polymorphisms (SNPs) interact with early life stressors in predicting levels of depression and anxiety. To replicate and extend these findings, we examined whether three literature-based OXTR SNPs (rs2254298, rs53576, rs2268498) interact with childhood maltreatment in the development of clinically diagnosed depression and anxiety disorders. Methods: We included 2567 individuals from the Netherlands Study of Depression and Anxiety. This sample consisted of 387 healthy controls, 428 people with a current or past depressive disorder, 243 people with a current or past anxiety disorder, and 1509 people with both lifetime depression and anxiety diagnoses. Childhood maltreatment was measured with both an interview and via self-report. Additional questionnaires measured depression and anxiety sensitivity. Results: Childhood maltreatment was strongly associated with both lifetime depression and anxiety diagnoses, as well as with depression and anxiety sensitivity. However, the OXTR SNPs did not moderate these associations nor had main effects on outcomes. Conclusions: The three OXTR gene SNPs did not interact with childhood maltreatment in predicting lifetime depression and anxiety diagnoses or sensitivity. This stresses the importance of replication studies with regard to OXTR gene variants in general populations as well as in clearly established clinical samples