Engineering topics

Chan, A

Publications and source records attributed to Chan, A.

4 records

DOE OSTI2021

Observation of synergy between lower hybrid waves at two frequencies in EAST

Synergistic effects between two frequencies of lower hybrid (LH) waves—operating at 2.45 and 4.6 GHz—were observed in experiment on EAST for the first time. At low density (n_e,lin ≈ 2.0 × 10^19m^−3), simultaneous injection of a 65/35 mix of 2.45 GHz/4.6 GHz power achieved an LHCD efficiency that was 25% higher than what should be expected from the linear combination of the two sources. The experiment was interpreted with time-dependent simulations, using the equilibrium and transport solver TRANSP, coupled with the ray-tracing code GENRAY and the Fokker-Planck solver CQL3D. For each discharge, profiles of current and hard x-ray from simulation and measurement agree within uncertainties. An examination of the electron distribution function indicates that the LH synergy is supported by the increased width of the LH resonance plateau in the simultaneous injection case compared to independent injection.

Lower hybrid synergy↗

DOE OSTI2012

Non-invasive Field Measurements of Soil Water Content Using a Pulsed 14 MeV Neutron Generator

Current techniques of soil water content measurement are invasive and labor-intensive. Here, we demonstrate that an in situ soil carbon (C) analyzer with a multi-elemental analysis capability, developed for studies of terrestrial C sequestration, can be used concurrently to non-invasively measure the water content of large-volume ({approx}0.3 m{sup 3}) soil samples. Our objectives were to investigate the correlations of the hydrogen (H) and oxygen (O) signals with water to the changes in the soil water content in laboratory experiments, and in an agricultural field. Implementing prompt gamma neutron activation analyses we showed that in the field, the signal from the H nucleus better indicates the soil water content than does that from the O nucleus. Using a field calibration, we were able to use the H signal to estimate a minimum detectable change of {approx}2% volumetric water in a 0-30 cm depth of soil.

08 HYDROGEN↗

DOE OSTI2011

Data Warehouse on the Web for Accelerator Fabrication And Maintenance

A data warehouse grew out of the needs for a view of accelerator information from a lab-wide or project-wide standpoint (often needing off-site data access for the multi-lab PEP-II collaborators). A World Wide Web interface is used to link legacy database systems of the various labs and departments related to the PEP-II Accelerator. In this paper, we describe how links are made via the 'Formal Device Name' field(s) in the disparate databases. We also describe the functionality of a data warehouse in an accelerator environment. One can pick devices from the PEP-II Component List and find the actual components filling the functional slots, any calibration measurements, fabrication history, associated cables and modules, and operational maintenance records for the components. Information on inventory, drawings, publications, and purchasing history are also part of the PEP-II Database. A strategy of relying on a small team, and of linking existing databases rather than rebuilding systems is outlined.

43 PARTICLE ACCELERATORS↗

DOE OSTI2011

A Components Database Design and Implementation for Accelerators and Detectors

Many accelerator and detector systems being fabricated for the PEP-II Accelerator and BABAR Detector needed configuration control and calibration measurements tracked for their components. Instead of building a database for each distinct system, a Components Database was designed and implemented that can encompass any type of component and any type of measurement. In this paper we describe this database design that is especially suited for the engineering and fabrication processes of the accelerator and detector environments where there are thousands of unique component types. We give examples of information stored in the Components Database, which includes accelerator configuration, calibration measurements, fabrication history, design specifications, inventory, etc. The World Wide Web interface is used to access the data, and templates are available for international collaborations to collect data off-line.

43 PARTICLE ACCELERATORS↗