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Flores, R.

Publications and source records attributed to Flores, R..

5 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

THE DARK ENERGY CAMERA

The Dark Energy Camera is a new imager with a 2.°2 diameter field of view mounted at the prime focus of the Victor M. Blanco 4 m telescope on Cerro Tololo near La Serena, Chile. The camera was designed and constructed by the Dark Energy Survey Collaboration and meets or exceeds the stringent requirements designed for the wide-field and supernova surveys for which the collaboration uses it. The camera consists of a five-element optical corrector, seven filters, a shutter with a 60 cm aperture, and a charge-coupled device (CCD) focal plane of 250 μm thick fully depleted CCDs cooled inside a vacuum Dewar. The 570 megapixel focal plane comprises 62 2k × 4k CCDs for imaging and 12 2k × 2k CCDs for guiding and focus. The CCDs have 15 μm × 15 μm pixels with a plate scale of 0.″263 pixel{sup −1}. A hexapod system provides state-of-the-art focus and alignment capability. The camera is read out in 20 s with 6–9 electron readout noise. This paper provides a technical description of the camera's engineering, construction, installation, and current status.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2014

The development of a cryogenic over-pressure pump

A cryogenic over-pressure pump (OPP) was tested in the prototype telescope liquid nitrogen (LN2) cooling system for the Dark Energy Survey (DES) Project. This OPP consists of a process cylinder (PC), gas generator, and solenoid operated valves (SOVs). It is a positive displacement pump that provided intermittent liquid nitrogen (LN2) flow to an array of charge couple devices (CCDs) for the prototype Dark Energy Camera (DECam). In theory, a heater submerged in liquid would generate the drive gas in a closed loop cooling system. The drive gas would be injected into the PC to displace that liquid volume. However, due to limitations of the prototype closed loop nitrogen system (CCD cooling system) for DECam, a quasiclosed-loop nitrogen system was created. During the test of the OPP, the CCD array was cooled to its designed set point temperature of 173K. It was maintained at that temperature via electrical heaters. The performance of the OPP was captured in pressure, temperature, and flow rate in the CCD LN2 cooling system at Fermi National Accelerator Laboratory (FNAL)

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2014

Current transport and thermoelectric properties of very high power factor Fe{sub 3}O{sub 4}/SiO{sub 2}/p-type Si(001) devices

The current transport and thermoelectric properties of Fe{sub 3}O{sub 4}/SiO{sub 2}/p-type Si(001) heterostructures with Fe{sub 3}O{sub 4} thicknesses of 150, 200, and 350 nm have been investigated between 100 and 300 K. We observe a sharp drop of the in-plane resistivity at 200 K due to the onset of conduction along the Si/SiO{sub 2} interface related to tunneling of electrons from the Fe{sub 3}O{sub 4} into the accumulation layer of holes at the Si/SiO{sub 2} interface, whose existence was confirmed by capacitance-voltage measurements and a two band analysis of the Hall effect. This is accompanied by a large increase of the Seebeck coefficient reaching +1000 μV/K at 300 K that is related to holes in the p-type Si(001) and gives a power factor of 70 mW/K{sup 2}m when the Fe{sub 3}O{sub 4} layer thickness is reduced down to 150 nm. We show that most of the current flows in the Fe{sub 3}O{sub 4} layer at 300 K, while the Fe{sub 3}O{sub 4}/SiO{sub 2}/p-type Si(001) heterostructures behave like tunneling p-n junctions in the transverse direction.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
NASA NTRS1984

Portable Plating System

Plating system mounted on portable cart includes 30-gallon (23.5 liter) electrolyte tank, filler pump, heaters, replenishing anodes, plating rectifiers and tank rectifier to continously remove contaminants.

Flores, R.↗