Daniel Chavez

New Magnet Technology for a 1.5 T Open-MRI Breast Imager

Structured windings and steel poles can be used to create a homogeneous field in a volume of interest (VOI) outside of a coil configuration. The methodology is explained and a first application to an optimized open-MRI imager for breast imaging is presented. Similar methods have been used to design a gradient coil set to similarly project uniform gradient into the same VOI. Aspects of the design and cryogenics of the magnet are discussed.

Strong Focusing Cyclotron and Its Applications

A Strong Focusing cyclotron has been developed by the Accelerator Research Lab at Texas A&M to produce up to 10 mA of proton beam at 800 MeV. The cyclotron has several innovations that allow it to achieve such high levels of power. The first is the superconducting RF cavities that provide sufficient gain to separate the orbits by a minimum of 6 cm. This space allows for beam transport channels to be place along every orbit and provide continuous quadrupole focusing. Additionally, a trim dipole is added to the channel to allow for corrections to the main dipole. This document will show the new BTC design that allows for the cyclotron to be greatly simplified. The main dipole is kept below saturation and is shaped to levitate the poles. The main dipole, along with the RF cavity, are designed such that several cyclotrons could be stacked on top of one another. This design provides the high power beam required for several applications. These applications include accelerator driven systems, neutron damage facilities, and medical isotope production. Texas A&M has developed two designs for ADS fission: an isoburner and an isobreeder. Both of these designs will be expounded on within the document. A design for a neutron damage facility and it capabilities are presented as well as a medical isotope production design. The SFC has great potential to revolutionize these fields and be of great service to the US.

Using eye-tracking to model attribute non-attendance in choice experiments

ABSTRACT We investigate revealed attribute attendance in discrete choice experiments using eye-tracking. A simple theoretical framework is proposed in which choices are a function of visual attention. Consistent with the existing literature, the assumption that participants use all the available information to make their decisions does not hold. The results also illustrate that model fit and predictive power are greatly increased by using visual attendance measures as regressors. The use of eye-tracking technology has value for measuring revealed attention and to benchmark with existing choice models.

Cable-in-Conduit Dipoles to Enable a Future Hadron Collider

We report the development of a new approach to dipole technology, based upon cable-in-conduit conductor, that optimizes the cost and performance for a future ultimate-energy hadron collider. Optimization of cost for an ultimate-energy hadron collider is dominated by the strong dependence of magnet cost and synchrotron radiation power upon the dipole field strength. Assuming that the collider is built at a site with minimum tunnel cost, the projected total project cost is minimum for a ∼4 T dipole field. We present a novel option in which the double-ring of magnets is housed in a circular pipeline, submerged with neutral buoyancy at a depth ∼100 m in the sea. Such a collider inscribed in the Gulf of Mexico would provide hadron collisions at 500-TeV energy with a luminosity of 5 × 1035 cm−2s−1. We describe here the design of the dipole and of the pipeline cryostat that would contain it.