Engineering topics

Rogers, C.

Publications and source records attributed to Rogers, C..

5 records

DOE OSTI2024

Transverse emittance reduction in muon beams by ionization cooling

Accelerated muon beams have been considered for the next-generation studies of high-energy lepton–antilepton collisions and neutrino oscillations. However, high-brightness muon beams have not yet been produced. The main challenge for muon acceleration and storage stems from the large phase-space volume occupied by the beam, derived from the production mechanism of muons through the decay of pions. The phase-space volume of the muon beam can be decreased through ionization cooling. Here we show that ionization cooling leads to a reduction in the transverse emittance of muon beams that traverse lithium hydride or liquid hydrogen absorbers in the Muon Ionization Cooling Experiment. Our results represent a substantial advance towards the realization of muon-based facilities that could operate at the energy and intensity frontiers.

43 PARTICLE ACCELERATORS↗

NASA NTRS1999

The 260: The Largest Solid Rocket Motor Ever Tested

Aerojet in the mid 1960s, under contract to NASA, built and static hot fire tested the largest solid rocket motor (SRM) in history for the purpose of demonstrating the feasibility of utilizing large SRMs for space exploration. This program successfully fabricated two high strength steel chambers, loaded each with approximately 1,68 million pounds of propellant, and static test fired these giants with their nozzles up from an underground silo located adjacent to the Florida everglades. Maximum thrust and total impulse in excess of 5,000,000 lbf and 3,470,000,000 lbf-sec were achieved. Flames from the second firing, conducted at night, were seen over eighty miles away. For comparative purposes: the thrust developed was nearly 100 times that of a Minuteman III second stage and the 260 in.-dia cross-section was over 3 times that of the Space Shuttle SRM.

Crimmins, P.↗

NASA NTRS1994

Arcmimute scale HI and IRAS observations toward high latitude cloud G86.5+59.6

G86.5+59.6 is a degree-sized high latitude cloud originally selected for investigation by Heiles, Reach, and Koo (1988) on the basis of its appearance on the IRAS Skyflux images at 60 and 100 micrometers. Because of the interesting possibility that this is an intermediate velocity cloud colliding with HI in the Galactic plane, we have examined this region further, both at low resolution over an extended field to provide some context and at higher (arcminute) resolution within the cloud.

Martin, Peter G.↗

NASA NTRS1992

Surface photometry of disk galaxies at 60 and 100 microns - Radial gradients in dust temperature in optically thin disks

Surface, aperture, and grid photometry are performed at 60 and 100 microns for a sample of 28 nearby, large angular size galaxies. The spatial resolution of the data is 0.5-2.0 kpc, which allows for a coarse investigation of predicted radial gradients in physical dust temperature. A model is derived which predicts a drop of 3 K for every optical scale length, and this model agrees well with the data. In addition, for a subsample of 16 galaxies the radial profile at 60 microns is directly compared with that in the B or I band. The model predicts that optically thick disks should have scale lengths a factor of two smaller at 60 microns compared to B. In the optically thin case, the scale lengths are about equal except for the effect of the gradient in dust temperature. Virtually all of the data support the prediction of the optically thin case. Finally, 10 galaxies in the sample have sufficient angular sizes to allow for a coarse 2D spatial mapping of the 60/100 microns flux ratio. These maps clearly reveal that, when present, small amounts of hot dust dominate the emission at 60 microns and effectively mask the existence of a much larger amount of cold dust.

Bothun, Gregory D.↗

NASA NTRS1972

Project Fog Drops. Part 1: Investigations of warm fog properties

A detailed study was made of the micrometeorological and microphysical characteristics of eleven valley fogs occurring near Elmira, New York. Observations were made of temperature, dew point, wind speed and direction, dew deposition, vertical wind velocity, and net radiative flux. In fog, visibility was continuously recorded and periodic measurements were made of liquid water content and drop-size distribution. The observations were initiated in late evening and continued until the time of fog dissipation. The vertical distribution of temperature in the lowest 300 meters and cloud nucleus concentration at several heights were measured from an aircraft before fog nucleus concentrations at several heights were measured from an aircraft before fog formation. A numerical model was developed to investigate the life cycle of radiation fogs. The model predicts the temporal evolution of the vertical distributions of temperature, water vapor, and liquid water as determined by the turbulent transfer of heat and moisture. The model includes the nocturnal cooling of the earth's surface, dew formation, fog drop sedimentation, and the absorption of infrared radiation by fog.

Pilie, R. J.↗