R. Nehring

Bio: R. Nehring is an academic researcher from Fermilab. The author has contributed to research in topics: Magnet & Electromagnetic coil. The author has an hindex of 7, co-authored 18 publications receiving 170 citations.

A Fast Continuous Magnetic Field Measurement System Based on Digital Signal Processors

Abstract: In order to study dynamic effects in accelerator magnets, such as the decay of the magnetic field during the dwell at injection and the rapid so-called "snapback" during the first few seconds of the resumption of the energy ramp, a fast continuous harmonics measurement system was required. A new magnetic field measurement system, based on the use of digital signal processors (DSP) and Analog to Digital (A/D) converters, was developed and prototyped at Fermilab. This system uses Pentek 6102 16 bit A/D converters and the Pentek 4288 DSP board with the SHARC ADSP-2106 family digital signal processor. It was designed to acquire multiple channels of data with a wide dynamic range of input signals, which are typically generated by a rotating coil probe. Data acquisition is performed under a RTOS, whereas processing and visualization are performed under a host computer. Firmware code was developed for the DSP to perform fast continuous readout of the A/D FIFO memory and integration over specified intervals, synchronized to the probe's rotation in the magnetic field. C, C++ and Java code was written to control the data acquisition devices and to process a continuous stream of data. The paper summarizes the characteristics of the system and presents the results of initial tests and measurements

Mu2e Transport Solenoid Prototype Tests Results

Abstract: The Fermilab Mu2e experiment has been developed to search for evidence of charged lepton flavor violation through the direct conversion of muons into electrons. The transport solenoid is an s-shaped magnet that guides the muons from the source to the stopping target. It consists of 52 superconducting coils arranged in 27 coil modules. A full-size prototype coil module, with all the features of a typical module of the full assembly, was successfully manufactured by a collaboration between INFN-Genoa and Fermilab. The prototype contains two coils that can be powered independently. To validate the design, the magnet went through an extensive test campaign. Warm tests included magnetic measurements with a vibrating stretched wire and electrical and dimensional checks. The cold performance was evaluated by a series of power tests and temperature dependence and minimum quench energy studies.

A Test of a 2 Tesla Superconducting Transmission Line Magnet System

Abstract: A Superconducting transmission line magnet test system for the stage 1 accelerator of a staged VLHC proton-proton collider has been built and operated at Fermilab. The 1.5 m long, twin-aperture, combined function dipole magnet of 2 Tesla field is excited by a single turn 100 kA transmission line superconductor. The 100 kA dc current is generated using dc-dc switching converters powered by a bulk 240 kW supply. A pair of horizontally placed conventional leads facilitates transfer of this current to the magnet transmission line superconductor operating at liquid helium temperature. Fabrication of magnet components and magnet assembly work are described. The magnet test system and its operation are presented, and the performance is summarized

Fast thermometry for superconducting RF cavity testing

Abstract: Fast readout of strategically placed low heat capacity thermometry can provide valuable information of Superconducting RF (SRF) cavity performance. Such a system has proven very effective for the development and testing of new cavity designs. Recently, several resistance temperature detectors (RTDs) were installed in key regions of interest on a new 9 cell 3.9 GHz SRF cavity with integrated HOM design at FNAL. A data acquisition system was developed to read out these sensors with enough time and temperature resolution to measure temperature changes on the cavity due to heat generated from multipacting or quenching within power pulses. The design and performance of the fast thermometry system will be discussed along with results from tests of the 9 cell 3.9 GHz SRF cavity.

Mechanical design of automatic cavity tuning machines

Abstract: Since 15 years a prototype semi automatic cavity tuning machine is used at DESY to tune field flatness and concentricity of TESLA [1] shape nine cell cavities for FLASH [2]. Based on this experience a further development work was done in a collaboration effort among FNAL, KEK and DESY to support the high throughput of series cavity productions necessary for new projects like the European XFEL [3], the ILC project, Project “X” and other SRF based future projects. Initially four machines were built within the collaboration at DESY. Two of them will be delivered and operated by the cavity vendors for tuning the XFEL cavities. The remaining two machines are delivered to FNAL for commissioning. One of them will be passed on to KEK. In the following the mechanical design and functionality of these machines is described. Special attention refers to safety aspects for the machines operation at industry and the fulfillment of requirements according to the EC directive of machinery.

The International Linear Collider Technical Design Report - Volume 3.I: Accelerator \& in the Technical Design Phase

Abstract: The International Linear Collider Technical Design Report (TDR) describes in four volumes the physics case and the design of a 500 GeV centre-of-mass energy linear electron-positron collider based on superconducting radio-frequency technology using Niobium cavities as the accelerating structures. The accelerator can be extended to 1 TeV and also run as a Higgs factory at around 250 GeV and on the Z0 pole. A comprehensive value estimate of the accelerator is give, together with associated uncertainties. It is shown that no significant technical issues remain to be solved. Once a site is selected and the necessary site-dependent engineering is carried out, construction can begin immediately. The TDR also gives baseline documentation for two high-performance detectors that can share the ILC luminosity by being moved into and out of the beam line in a "push-pull" configuration. These detectors, ILD and SiD, are described in detail. They form the basis for a world-class experimental programme that promises to increase significantly our understanding of the fundamental processes that govern the evolution of the Universe.

Modern and Future Colliders

Abstract: Since the initial development of charged particle colliders in the middle of the 20th century, these advanced scientific instruments have been at the forefront of scientific discoveries in high energy physics over the past 60 years. Collider accelerator technology and beam physics have progressed immensely and modern facilities now operate at energies and luminosities many orders of magnitude greater than the pioneering colliders of the early 1960s. In addition, the field of colliders remains extremely dynamic and continues to develop many innovative approaches. Indeed, several novel concepts are currently being considered for designing and constructing even more powerful future colliders. In this paper, we first review the colliding beam method and the history of colliders, and then present, in detail, the major achievements of operational machines and the key features of near-term collider projects that are currently under development. We conclude with an analysis of numerous proposals and studies for far-future colliders. The evaluation of their respective potentials reveals tantalizing prospects for further significant breakthroughs in the collider field.

Application of PCB and FDM Technologies to Magnetic Measurement Probe System Development

Abstract: Rotating coil probes are essential for measuring harmonic multipole fields of accelerator magnets. A fundamental requirement of these probes is their accuracy, which typically implies that the probes need to be very stiff and straight, have highly accurate knowledge of the placement of windings, and an ability to buck the fundamental fields well in order to suppress the effects of vibrations. Ideally, for an R&D test environment, probe fabrication should also be easy and low-cost, so that probe parameters (type, length, number of turns, radius, etc.) can be customized to the magnet requiring test. Such facility allows measurement optimization for magnets of various multipolarity, aperture size, cable twist pitch, etc. The accuracy and construction flexibility aspects of probe development, however, are often at odds with each other. This paper reports on application of printed-circuit board and fused-deposition modeling technologies, and what these offer to the fabrication of magnetic measurement probe systems.

Digital Integrator for Fast Accurate Measurement of Magnetic Flux by Rotating Coils

Abstract: A fast digital integrator (FDI) with dynamic accuracy and a trigger frequency higher than those of a portable digital integrator (PDI), which is a state-of-the-art instrument for magnetic measurements based on rotating coils, was developed for analyzing superconducting magnets in particle accelerators. Results of static and dynamic metrological characterization show how the FDI prototype is already capable of overcoming the dynamic performance of PDI as well as covering operating regions that used to be inaccessible

The International Linear Collider

Abstract: In this paper, we describe the key features of the recently completed technical design for the International Linear Collider (ILC), a 200–500 GeV linear electron–positron collider (expandable to 1 TeV) that is based on 1.3 GHz superconducting radio-frequency (SCRF) technology. The machine parameters and detector characteristics have been chosen to complement the Large Hadron Collider physics, including the discovery of the Higgs boson, and to further exploit this new particle physics energy frontier with a precision instrument. The linear collider design is the result of nearly 20 years of R&D, resulting in a mature conceptual design for the ILC project that reflects an international consensus. We summarize the physics goals and capability of the ILC, the enabling R&D and resulting accelerator design, as well as the concepts for two complementary detectors. The ILC is technically ready to be proposed and built as a next generation lepton collider, perhaps to be built in stages beginning as a Higgs factory.