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Levin, Daniel

Publications and source records attributed to Levin, Daniel.

5 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Studies of Cherenkov photon production in PbF 2 crystals using proton beams at Fermilab

Future lepton colliders such as the FCC-ee, CEPC, ILC, or a muon collider will collect large data samples that allow precision physics studies with unprecedented accuracy, especially when the data is collected by innovative state-of-the-art detectors. An electromagnetic calorimeter based on scintillating crystals, designed to separately record Cherenkov and scintillation light, can achieve precision measurements of electrons and photons without sacrificing jet energy resolution, given adequate light collection efficiency and separation. This paper presents initial measurements from a program aimed at developing such a calorimeter system for future colliders. Finally, we focus on using PbF 2 crystals to enhance the understanding of Cherenkov light collection, marking the first step in this endeavor.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRS1991

Static measurements of slender delta wing rolling moment hysteresis

Slender delta wing planforms are susceptible to self-induced roll oscillations due to aerodynamic hysteresis during the limit cycle roll oscillation. Test results are presented which clearly establish that the static rolling moment hysteresis has a damping character; hysteresis tends to be greater when, due to either wing roll or side slip, the vortex burst moves back and forth over the wing trailing edge. These data are an indirect indication of the damping role of the vortex burst during limit cycle roll oscillations.

Katz, Joseph↗
NASA NTRS1991

Measurement of the static and dynamic coefficients of a cross-type parachute in subsonic flow

An experimental parametric investigation of the aerodynamic qualities of cross-type parachutes was performed in a subsonic wind tunnel, using a new experimental technique. This investigation included the measurement of the static and dynamic aerodynamic coefficients, utilizing the measuring apparatus modified specifically for this type of testing. It is shown that the static aerodynamic coefficients of several configurations are in good agreement with available data, and assisted in validating the experimental technique employed. Two configuration parameters were varied in the static tests, the cord length and the canopy aspect ratio, with both parameters having a similar effect on the drag measurement, i.e., any increase in either of them increased the effective blocking area, and therefore the axial force.

Shpund, Zalman↗
NASA NTRS1990

Self-induced roll oscillations of low-aspect-ratio rectangular wings

Experimental investigation of small aspect ratio rectangular wings mounted on a free-to-roll sting balance indicated that self-induced roll oscillations are possible when the aspect ratio of such wings is less than 0.5. The oscillations are probably driven by the periodic changes in the location and strength of the side edge vortices, as it has been shown for the 'wing rock' motion of delta wings, where similar changes in the leading edge vortex strength and position cause the roll oscillations. During the roll oscillation cycle the roll angle, normal force, and the side force were recorded and presented for three wings with aspect ratios of 0.25, 0.35, and 0.47. This data indicates that the lift loss during roll oscillations of rectangular wings is less than what was measured for similar delta wings. Also, the flow field of such slender rectangular wings at high angles of attack is more complicated due to the additional leading edge vortex, when compared with the flow field over slender delta wings.

Levin, Daniel↗