Engineering topics

Rodriguez, A.

Publications and source records attributed to Rodriguez, A..

6 records

DOE OSTI2024

Modeling and Characterization of TES-Based Detectors for the Ricochet Experiment

Coherent elastic neutrino-nucleus scattering (CE nu NS) offers a valuable approach in searching for physics beyond the standard model. The Ricochet experiment aims to perform a precision measurement of the CE nu NS spectrum at the Institut Laue-Langevin nuclear reactor with cryogenic solid-state detectors. The experiment plans to employ an array of cryogenic thermal detectors, each with a mass of around 30 g and an energy threshold of below 100 eV. The array includes nine detectors read out by transition-edge sensors (TES). These TES-based detectors will also serve as demonstrators for future neutrino experiments with thousands of detectors. In this article, we present an update on the characterization and modeling of a prototype TES detector.

Chang, C. L.↗

DOE OSTI2024

Properties of Low Tc AlMn TES

Low Tc AlMn transition-edge sensors (TESs) have been developed as sensitive thermometers for the Q-Array, which will use superconducting targets to measure the coherent elastic neutrino nucleus scattering spectrum in the RICOCHET experiment. The TESs are made of manganese-doped aluminum with a titanium and gold antioxidation layer. A prototype TES thermometer consists of two TESs in parallel, an input gold pad in metallic contact with the TESs and an output gold pad and gold thermal link meanders, which are each designed to control the flow of heat through the TESs. We have fabricated and measured low TC AlMn TES chips with or without thermal flow control structures. We present TC measurements of the TESs after the initial fabrication and further TC tuning by re-heating and summarize the thermal property studies of the prototype TES thermometer by measuring I-V curves and complex impedance.

Coherent elastic neutrino nucleus scattering, Cryo↗

NASA NTRS1992

The RBE-LET relationship for rodent intestinal crypt cell survival, testes weight loss, and multicellular spheroid cell survival after heavy-ion irradiation

This report presents data for survival of mouse intestinal crypt cells, mouse testes weight loss as an indicator of survival of spermatogonial stem cells, and survival of rat 9L spheroid cells after irradiation in the plateau region of unmodified particle beams ranging in mass from 4He to 139La. The LET values range from 1.6 to 953 keV/microns. These studies examine the RBE-LET relationship for two normal tissues and for an in vitro tissue model, multicellular spheroids. When the RBE values are plotted as a function of LET, the resulting curve is characterized by a region in which RBE increases with LET, a peak RBE at an LET value of 100 keV/microns, and a region of decreasing RBE at LETs greater than 100 keV/microns. Inactivation cross sections (sigma) for these three biological systems have been calculated from the exponential terminal slope of the dose-response relationship for each ion. For this determination the dose is expressed as particle fluence and the parameter sigma indicates effect per particle. A plot of sigma versus LET shows that the curve for testes weight loss is shifted to the left, indicating greater radiosensitivity at lower LETs than for crypt cell and spheroid cell survival. The curves for cross section versus LET for all three model systems show similar characteristics with a relatively linear portion below 100 keV/microns and a region of lessened slope in the LET range above 100 keV/microns for testes and spheroids. The data indicate that the effectiveness per particle increases as a function of LET and, to a limited extent, Z, at LET values greater than 100 keV/microns. Previously published results for spread Bragg peaks are also summarized, and they suggest that RBE is dependent on both the LET and the Z of the particle.

Non-NASA Center↗

NASA NTRS1988

The effect of Co alloying content on the kinetics of reaction zone growth in tungsten fiber reinforced superalloy composites

A Co-free modified superalloy similar in composition to Waspaloy is investigated in an effort to understand the effect of Co on reaction zone growth kinetics and verify the chemistry dependence of reaction zone growth in the matrix of tungsten fiber reinforced superalloy composites. The values of the parabolic rate constant, characterizing the kinetics of reaction zone growth, for the Waspaloy matrix and the C-free alloy as well as five other alloys from a previous study confirm the dependence of reaction zone growth kinetics on cobalt content of the matrix. The Co-free alloy composite exhibits the slowest reaction zone growth among all tungsten fiber reinforced composites studied to date.

Rodriguez, A.↗

NASA NTRS1985

Mechanistic studies related to the safety of Li/SOCl2 cells

Mechanistic studies of the reactions in Li-SOCl2 cells have been undertaken to improve understanding of the safety problems of these cells. The electrochemical reduction of 1.5M LiAlCl4/SOCl2 has been investigated using gas chromatography, electron spin resonance spectroscopy, and infrared spectroscopy. Cl2 and S2Cl2 have been identified as intermediates in the reduction of SOCl2, along with a radical species (g/xx/ = 2.004, g/yy/ = 2.016, g/zz/ = 2.008) and the proposed triplet ground-state dimer of this radical. SO2 and sulfur have been identified as products. Based upon these findings, a mechanism for the electrochemical reduction of 1.5M LiAlCl4/SOCl2 has been proposed, and its implications for safety of Li-SOCl2 cells during discharge to +0.5V at 25-30 C are discussed.

Carter, B. J.↗

NASA NTRS1982

Lithium-thionyl chloride battery safety

Primary lithium cells which use LiAlCl4/SOCl2 electrolyte exhibit high energy density and long life. Currently these cells pose a safety problem since they have been found to vent or explode. This paper summarizes experiments to resolve the safety problem of Li-SOCl2 cells by thermal modeling and identification of possibly hazardous intermediates formed during discharge of these cells. A thermal model and mechanism for the reduction of SOCl2 are presented, as well as a discussion of their application to Li-SOCl2 cell safety.

Carter, B.↗