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Brennan, M.

Publications and source records attributed to Brennan, M..

9 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Experimental Demonstration of Hadron Beam Cooling Using Radio-Frequency Accelerated Electron Bunches

Cooling of beams of gold ions using electron bunches accelerated with radio-frequency systems was recently experimentally demonstrated in the Relativistic Heavy Ion Collider at Brookhaven National Laboratory. Such an approach is new and opens the possibility of using this technique at higher energies than possible with electrostatic acceleration of electron beams. The challenges of this approach include generation of electron beams suitable for cooling, delivery of electron bunches of the required quality to the cooling sections without degradation of beam angular divergence and energy spread, achieving the required small angles between electron and ion trajectories in the cooling sections, precise velocity matching between the two beams, high-current operation of the electron accelerator, as well as several physics effects related to bunched-beam cooling. Here we report on the first demonstration of cooling hadron beams using this new approach.

43 PARTICLE ACCELERATORS↗
NASA NTRS2017

First Time-Resolved Observations of Precipitation Structure and Storm Intensity with a Constellation of Smallsats (TROPICS) Mission Applications Workshop Summary Report

The National Aeronautics and Space Administration (NASA) Time-Resolved Observations of Precipitation structure and storm Intensity with a Constellation of SmallSats (TROPICS) mission is a constellation of state-of-the-science observing platforms that will measure temperature and humidity soundings and precipitation with spatial resolution comparable to current operational passive microwave sounders but with unprecedented temporal resolution. TROPICS is a cost-capped ($30 million) Venture-class mission funded by the NASA Earth Science Division (ESD) and led by principal investigator Dr. William Blackwell from the Massachusetts Institute of Technology Lincoln Laboratory (MIT LL). The mission is comprised of a constellation of six, three-unit (3U) Cube-Sats (approximately 10 by 10 by 34 centimeters), each hosting a 12-channel passive microwave spectrometer based on the Micro-sized Microwave Atmospheric Satellite 2 (MicroMAS-2) developed at MIT LL. TROPICS will provide imagery at frequencies near 91 and 205 gigahertz, temperature sounding near 118 gigahertz, and moisture sounding near 183 gigahertz. Spatial resolution at nadir will be around 27 kilometers for temperature and 17 kilometers for moisture and precipitation with a swath width of approximately 2,000 kilometers. Both the spatial resolution and swath width are similar to the Advanced Technology Microwave Sounder (ATMS) that is being flown as part of the Suomi National Polar-Orbiting Partnership and will fly starting in 2017 on the National Oceanic and Atmospheric Administration (NOAA) Joint Polar Satellite System (JPSS). In addition, TROPICS meets many of the requirements outlined in the 2007 Decadal Survey for the Precision and All-Weather Temperature and Humidity mission, which was originally envisioned as a microwave instrument in geostationary orbit. TROPICS enables temporal resolution similar to geostationary orbit but at a much lower cost, demonstrating a technology that could impact the design of future Earth-observing missions. The satellites for the TROPICS mission are slated for delivery to NASA in 2019 for launches planned no earlier than 2020. The primary mission objective of TROPICS is to relate temperature, humidity, and precipitation structure to the evolution of tropical cyclone (TC) intensity.

applied scienc↗
DOE OSTI2015

Report of the eRHIC Ring-Ring Working Group

This report evaluates the ring-ring option for eRHIC as a lower risk alternative to the linac-ring option. The reduced risk goes along with a reduced initial luminosity performance. However, a luminosity upgrade path is kept open. This upgrade path consists of two branches, with the ultimate upgrade being either a ring-ring or a linac-ring scheme. The linac-ring upgrade could be almost identical to the proposed linac-ring scheme, which is based on an ERL in the RHIC tunnel. This linac-ring version has been studied in great detail over the past ten years, and its significant risks are known. On the other hand, no detailed work on an ultimate performance ring-ring scenario has been performed yet, other than the development of a consistent parameter set. Pursuing the ring-ring upgrade path introduces high risks and requires significant design work that is beyond the scope of this report.

43 PARTICLE ACCELERATORS↗
DOE OSTI2012

Beam-beam effects with stochastic cooling in the 2012 RHIC 100 GeV heavy ion run

The 3-D stochastic cooling has been implemented in RHIC for the first time in the 2012 heavy ion run. In the U-U run, the U beam’s transverse emittances were cooled from initially about 13.5 mm.mrad down to 2.5 mm.mrad. The beam-beam parameters reached a maximum of -0.005. In the Cu-Au run, due to the unbalanced transverse beam sizes of the Cu and Au beams in the first several hours at the store, the Cu beam lifetime was significantly reduced by the beam-beam interaction. To maintain the Cu beam lifetime and to maximize the integrated luminosity, we intentionally reduced the cooling rate for the Au beam until the Cu beam got cooled. In this article, we review the beambeam effects in the 2012 RHIC heavy ion run and carry out numerical simulations to interpret the observations.

43 PARTICLE ACCELERATORS↗
DOE OSTI2012

Beam-Beam Effects with Stochastic Cooling in the 2012 RHIC 100 GEV Heavy Ion Run

The 3-D stochastic cooling has been implemented in RHIC for the first time in the 2012 heavy ion run. In the U-U run, the U beam’s transverse emittances were cooled from initially about 13.5 mm.mrad down to 2.5 mm.mrad. The beam-beam parameters reached a maximum of -0.005. In the Cu-Au run, due to the unbalanced transverse beam sizes of the Cu and Au beams in the first several hours at the store, the Cu beam lifetime was significantly reduced by the beam-beam interaction. To maintain the Cu beam life-time and to maximize the integrated luminosity, we intentionally reduced the cooling rate for the Au beam until the Cu beam got cooled. In this article, we review the beam-beam effects in the 2012 RHIC heavy ion run and carry out numerical simulations to interpret the observations.

43 PARTICLE ACCELERATORS↗
NASA NTRS1990

Fly-by-light technology development plan

The driving factors and developments which make a fly-by-light (FBL) viable are discussed. Documentation, analyses, and recommendations are provided on the major issues pertinent to facilitating the U.S. implementation of commercial FBL aircraft before the turn of the century. Areas of particular concern include ultra-reliable computing (hardware/software); electromagnetic environment (EME); verification and validation; optical techniques; life-cycle maintenance; and basis and procedures for certification.

Todd, J. R.↗