S. Kotelnikov

A Configurable Component-Based Software System for Magnetic Field Measurements

A new software system to test accelerator magnets has been developed at Fermilab. The magnetic measurement technique involved employs a single stretched wire to measure alignment parameters and magnetic field strength. The software for the system is built on top of a flexible component-based framework, which allows for easy reconfiguration and runtime modification. Various user interface, data acquisition, analysis, and data persistence components can be configured to form different measurement systems that are tailored to specific requirements (e.g., involving magnet type or test stand). The system can also be configured with various measurement sequences or tests, each of them controlled by a dedicated script. It is capable of working interactively as well as executing a pre-selected sequence of tests. Each test can be parameterized to fit the specific magnet type or test stand requirements. The system has been designed with portability in mind and is capable of working on various platforms, such as Linux, Solaris, and Windows. It can be configured to use a local data acquisition subsystem or a remote data acquisition computer, such as a VME processor running VxWorks. All hardware-oriented components have been developed with a simulation option that allows for running and testing measurements in the absence of data acquisition hardware

Quench Tests of

Two Cu stabilized Nb3Al strands, Fl (Nb matrix) and F3 (Ta matrix), fabricated at NIMS were wound into Rutherford cables at Fermilab in collaboration with NIMS. A small race-track magnet using Fl Rutherford cable, the first Nb3Al dipole magnet in the world, was constructed and tested to full current at Fermilab. This magnet was tested extensively to full short sample data and its quench characteristics were studied and reported. The 3-D magnetic field calculation was done with ANSYS to find the peak field. The quench characteristics of the magnet are explained with the characteristics of the Nb3Al strand and Rutherford cable. The small racetrack magnet built using Ta matrix F3 strand was constructed and will be tested in the near future. The advantages and disadvantages of these Nb3Al cables are briefly discussed.

{\rm Nb}_{3}{\rm Al}

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.

Small Racetrack Magnets

In collaboration between NIMS and Fermilab, we have made copper stabilized Nb3Al Rutherford cables, using Nb-matrixed and Ta-matrixed strands. First these cables were investigated at high current in low self field using a flux pump. Using these Rutherford cables, we built and tested small racetrack magnets. The magnet made with the Nb-matrixed strand showed the flux jump instability in low field. The small racetrack magnet wound with the Ta-matrixed Nb3Al Rutherford cable was very stable at 4.5 K operation without any instability, as well as at 2.2 K operation. With the successful operation of the small racetrack magnet up to its short sample data, the feasibility of the Nb3Al strand and its Rutherford cable for their application to high field magnets is established. The characteristics of Nb3Al Rutherford cable is compared with that of the Nb3Sn Rutherford cable and the advantages of Nb3Al Rutherford cable are discussed.

Mu2e Transport Solenoid Prototype Tests Results

A system employing an array of inductive pick-up coils around the perimeter of a cylinder has been developed for measurements of the rapidly changing field in the new corrector magnets for the Fermilab Booster. The coils are fabricated on printed circuit boards and feature windings which buck dipole, quadrupole, and sextupole fields, allowing sensitive measurements of both strength and higher-order harmonics. The array of coils is simultaneously sampled at data rates of up to 100 kHz with 10 kHz bandwidth using 24-bit ADCs.

Quench Tests and FEM Analysis of

A superconducting quadrupole magnet with splittable yoke has been designed for use in ILC Main Linac (ML) cryomodules. The splittable yoke allows assembly around the beam pipe, to avoid potential contamination of the superconducting RF cavities. The magnet is cooled by conduction and covers the full range of required ML field gradients. A critical requirement is stability of the magnetic center, at the level of 5 μm, for a 20% variation of the operating field. We report here the results of thermal, quench, and magnetic performance tests of a prototype splittable quadrupole, that were made up to the maximum design operating gradient in a conduction-cooled test cryostat.

{\rm Nb}_{3}{\rm Al}

The solenoid test facility at Fermilab was built using a large vacuum vessel for testing of conduction-cooled superconducting solenoid magnets, and was first used to determine the performance of the MICE coupling coil. The facility was modified recently to enable the testing of solenoid magnets for the muon-to-electron (Mu2e) experiment, which operates at much higher current than the coupling coil. One pair of low-current conduction-cooled copper and NbTi leads was replaced with two pairs of 10-kA high-temperature superconducting leads cooled by heat exchange with liquid nitrogen and liquid helium. The new design, with additional control and monitoring capability, also provides helium cooling of the superconducting magnet leads by conduction. A high current power supply with energy extraction was added, and several improvements to the quench protection and characterization system were made. Here, we present details of these changes and report on performance results from a test of the Mu2e prototype transport solenoid (TS) module. Progress on additional improvements in preparation for production TS module testing will be presented.

Rutherford Cables and Small Racetrack Magnets

The NOvA long-baseline neutrino oscillation experiment is receiving record numbers of 120GeV protons on target from Fermilabs NuMI neutrino beam. We take advantage of our experiment’s sophisticated particle identification algorithms to search for Lightweight Dark Matter (LDM) in the first year of data from the Near Detector of NOvA (300-ton low-Z mass, placed off the beam axis) during the experiment’s first physics runs. Theoretical models of LDM predict that bellow-10GeV candidates produced in the NuMI target might scatter or decay in the NOvA Near Detector. We simulate an example of the Neutral Vector Portal model with the sensitivity estimate of 10e-39 cm2, which corresponds to O(10) LDM candidates per three years of data, looking at single electromagnetic showers between 5 and 15 GeV in a model independent way.

A Fast-Sampling, Fixed Coil Array for Measuring the AC Field of Fermilab Booster Corrector Magnets

The NOvA long-baseline neutrino oscillation experiment is getting record numbers of 120GeV protons on target from Fermilabs NuMI neutrino beam. We take advantage of the sophisticated particle identification algorithms of the experiment to search for Lightweight Dark Matter (LDM) in the first year of data from the 300-ton, off-axis, low-Z, Near Detector of NOvA during the experiment’s first physics runs. LDM models predict that under-10 GeV candidates produced in the NuMI target might scatter or decay in the Near Detector. We simulate an example of the Neutral Vector Portal model with the sensitivity estimate of 10^(-39) cm^2, which corresponds to O(10) LDM candidates per three years of data, looking at single EM showers between 5 and 15 GeV in a model independent way.

Magnetic and Thermal Performance of a Conduction-Cooled Splittable Quadrupole

Using the NuMI beam at Fermilab and the NOvA near detector, we study the process by which a muon neutrino elastically scatters off an electron in the detector to produce a very forward going electromagnetic shower. By comparing dE/dx for various particle hypotheses for both longitudinal and transverse directions in a multilayer perceptron neural network, we trained a Particle ID algorithm to identify the scattered electron in an inclusive dataset. Muon-neutrino-on-e elastic scattering provides a clean, purely leptonic process free from nuclear effects for understanding neutral current scattering and constraining the NuMI beam flux. Also, this technique can be applied in two broad areas of beyond the standard model physics: a large neutrino transition magnetic moment and light dark matter particles produced in the NuMI target, both of which would create an energy dependent enhancement in the elastic scattering cross section.