The e+–H experiment of the Bielefeld–Brookhaven collaboration

1996 ◽  
Vol 74 (7-8) ◽  
pp. 361-366 ◽  
Author(s):  
W. Raith ◽  
A. Hofmann ◽  
M. Weber ◽  
K. G. Lynn
Keyword(s):  
Cross Sections ◽  
High Intensity ◽  
National Laboratory ◽  
Positron Beam ◽  
Theoretical Work ◽  
Brookhaven National Laboratory ◽  
Experimental Results ◽  
Experimental Setup ◽  
Open Questions ◽  
Remaining Time

The Bielefeld–Brookhaven collaboration began in 1989 and was originally scheduled for a duration of three and then six years and has recently been extended for about one more year. It will end in 1996 for reasons of manpower and funding. The goal of this collaboration was to measure integral and differential e+–H cross sections by employing the high-intensity positron beam (HIP) of the Brookhaven National Laboratory, anticipated to provide an electrostatically guided beam of 109 moderated positrons s−1. This goal has not yet been reached. Over all these years, the HIP operation has been suffering from a variety of technical difficulties, despite the great efforts of all parties involved. Nevertheless, since the HIP situation is improving, we will continue this collaboration and try to reach the goal within the remaining time. Our experimental results obtained with low-current positron beams thus far are discussed together with related experimental and theoretical work of other groups. Particular attention is given to open questions. The present experimental setup at the Brookhaven National Laboratory is described in detail. The planned measurements are outlined in order of their priority.

Search for new particles

1977 ◽  
Vol 355 (1683) ◽  
pp. 493-513
Keyword(s):  
Mass Spectrum ◽  
Proton Beam ◽  
High Intensity ◽  
National Laboratory ◽  
Brookhaven National Laboratory ◽  
New Type ◽  
New Particles

We present a description of an experiment carried out at the 30GeV Alternating Gradient Synchrotron of the Brookhaven National Laboratory. The experiment used a high intensity slow extracted proton beam of between 10 10 and 2 × 10 12 protons per pulse and measured the e + e - mass spectrum from the reaction p+Be→e + e - +X. The result of this experiment shows the production of a new type of particle, J, which decays to e + e - with a width consistent with zero. Experimental searches for more new particles will also be presented.

Experimental results from the Brookhaven National Laboratory test electron beam ion source

1998 ◽  
Vol 69 (2) ◽  
pp. 640-642 ◽  
Author(s):  
E. Beebe ◽  
J. Alessi ◽  
A. Hershcovitch ◽  
A. Kponou ◽  
A. Pikin ◽  
...  
Keyword(s):  
Electron Beam ◽  
Laboratory Test ◽  
National Laboratory ◽  
Brookhaven National Laboratory ◽  
Ion Source ◽  
Experimental Results ◽  
Test Electron

Side‐looking underground radar (SLUR): Physical modeling and case history

Geophysics ◽  
1998 ◽  
Vol 63 (6) ◽  
pp. 1925-1932 ◽  
Author(s):  
Jeffrey J. Daniels ◽  
James Brower
Keyword(s):  
Cross Sections ◽  
Ground Penetrating Radar ◽  
Physical Modeling ◽  
National Laboratory ◽  
Brookhaven National Laboratory ◽  
Plan View ◽  
Different Depths ◽  
Ground Penetrating ◽  
Oriented Object ◽  
Horizontal Layers

A modification of conventional surface ground‐penetrating radar (GPR) was conceived, tested, and successfully applied in the field at Brookhaven National Laboratory (BNL) to investigate waste pits. The modified GPR method consists of making measurements along a traverse line in a sloping trench with the radar’s antenna oriented at an angle of up to 45° from the horizontal. The direction of propagation of the electromagnetic field for this configuration is not vertical, and the amount of energy scattered from objects that are oriented vertically relative to the energy scattered from horizontal layers is increased. This fundamental feature of side‐looking underground radar (SLUR) measurements is illustrated by physical modeling. Measurements made along parallel trenches that are offset at different distances from a vertically oriented object provides GPR cross‐sections with a primary plane of investigation that intersects the vertical feature at different depths. SLUR was used at BNL in conjunction with conventional surface GPR measurements (displayed as 3-D blocks and plan‐view time slices) to enhance the vertical definition and improve the depth estimates of the waste pits.

MATTER AT HIGH DENSITY AND TEMPERATURE AT RHIC

2005 ◽  
Vol 20 (22) ◽  
pp. 5224-5233
Author(s):  
J. C. DUNLOP
Keyword(s):  
National Laboratory ◽  
Dense Matter ◽  
Theoretical Work ◽  
Heavy Ion ◽  
Brookhaven National Laboratory ◽  
High Density ◽  
Current Investigation ◽  
Relativistic Heavy Ion Collider ◽  
Quantitative Measurements ◽  
The Status

The status of current investigation of hot and dense matter at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) is reviewed. Indications for the creation of a dense, strongly interacting system have been seen. Further experimental and theoretical work is needed to convert these indications into quantitative measurements of the properties of the system created.

PION-INDUCED FISSION OF 209Bi AND 119Sn: MEASUREMENTS, CALCULATIONS, ANALYSES AND COMPARISON

2011 ◽  
Vol 20 (08) ◽  
pp. 1709-1722
Author(s):  
MUKHTAR AHMED RANA ◽  
GUL SHER ◽  
SHAHID MANZOOR ◽  
M. I. SHEHZAD
Keyword(s):  
Cross Sections ◽  
Fission Fragment ◽  
National Laboratory ◽  
Fission Cross Section ◽  
Computer Code ◽  
Brookhaven National Laboratory ◽  
Statistical Weight ◽  
Weight Functions ◽  
Nuclear Track Detector ◽  
Induced Fission

Cross-sections for the π--induced fission of 209 Bi and 119 Sn have been measured using the most sensitive CR-39 solid-state nuclear track detector. In experiments, target–detector stacks were exposed to negative pions of energy 500, 672, 1068, and 1665 MeV at the Brookhaven National Laboratory, USA. An important aspect of the present paper is the comparison of pion-induced fission fragment spectra of above mentioned nuclei with the spontaneous fission fragment spectra of 252 Cf . This comparison is made in terms of fission fragment track lengths in the CR-39 detectors. Measurement results are compared with calculations of Monte Carlo and statistical weight functions methods using the computer code CEM95. Agreement between measurements and calculations is fairly good for 209 Bi target nuclei whereas it is indigent for the case of 119 Sn . The possibilities of the trustworthy calculations, using the computer code CEM95, comparable with measurements of pion-induced fission in intermediate and heavy nuclei are explored by employing various systematics available in the code. Energy dependence of pion-induced fission in 119 Sn and 209 Bi is analyzed employing a newly defined parameter geometric-size-normalized fission cross-section [Formula: see text]. It is found that the collective nuclear excitations, which may lead to fission, become more probable for both 209 Bi and 119 Sn nuclei with increasing energy of negative pions from 500 to 1665 MeV .

scholarly journals Present Status of Neutron-, Photo-induced and Spontaneous Fission Yields Experimental Data

2020 ◽  
Vol 242 ◽  
pp. 02001
Author(s):  
B. Pritychenko ◽  
O. Schwerer ◽  
J. Totans ◽  
O. Gritzay
Keyword(s):  
Nuclear Reaction ◽  
Cross Sections ◽  
Spontaneous Fission ◽  
National Laboratory ◽  
Nuclear Data ◽  
Brookhaven National Laboratory ◽  
Data Sets ◽  
Scientific Publications ◽  
Reaction Data ◽  
Fission Yields

Nuclear reaction data collection, evaluation and dissemination have been pioneered at the Brookhaven National Laboratory since the early 50s. These activities gained popularity worldwide, and around 1970 the experimental nuclear reaction data interchange or exchange format (EXFOR) was established. The original EXFOR compilation scope consisted only of neutron reactions and spontaneous fission data, while many other nuclear data sets were ignored. Due to the high cost of new experiments, it is very important to find and recover the previously disregarded data using scientific publications, data evaluations and nuclear databases comparisons. Fission yields play a very important role in applied and fundamental physics, and such data are essential in many applications. The comparative analysis of Nuclear Science References (NSR) and Experimental Nuclear Reaction (EXFOR) databases shows a large number of unaccounted experiments and provides a guide for the recovery of fission cross sections, yields and covariance data sets. The dedicated fission yields data compilation effort is currently underway in the Nuclear Reaction Data Centers (NRDC) network, and includes identification, compilation, storage and Web dissemination of the recovered data sets.

PION-NUCLEON CHARGE EXCHANGE MEASUREMENTS IN THE REGION OF THE P11(1440) RESONANCE

2005 ◽  
Vol 20 (08n09) ◽  
pp. 1814-1817
Author(s):  
◽  
MICHAEL E. SADLER
Keyword(s):  
Charge Exchange ◽  
Cross Sections ◽  
National Laboratory ◽  
Brookhaven National Laboratory ◽  
Roper Resonance ◽  
Liquid Hydrogen Target ◽  
Hydrogen Target ◽  
Crystal Ball ◽  
Pion Nucleon ◽  
Baryon Spectroscopy

Measurements of differential cross sections for pion-nucleon charge exchange, π-p→π0n, in the region of the P11(1440), or Roper, resonance are presented. These data were obtained as part of the baryon spectroscopy program using the Crystal Ball detector at the Alternating Gradient Synchrocyclotron (AGS) at Brookhaven National Laboratory (BNL). Data were taken in 1998 with a liquid hydrogen target and in 2002 with CH 2 and C targets.

scholarly journals Heavy Ion Physics and Quark-Gluon Plasma

2005 ◽  
Vol 20 (14) ◽  
pp. 2951-2962 ◽  
Author(s):  
J. L. Nagle
Keyword(s):  
Coming Out ◽  
National Laboratory ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Brookhaven National Laboratory ◽  
Experimental Results ◽  
Relativistic Heavy Ion Collider ◽  
Heavy Ion Physics ◽  
Strongly Coupled ◽  
American Physical

These proceedings represent a brief overview of the exciting physics coming out from the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. The experimental results from BRAHMS, PHOBOS, PHENIX and STAR indicate a strongly-coupled state of matter that can only be described on the partonic level. We review some of the latest experimental results as we presented at the meeting of the Division of Particles and Fields of the American Physical Society in Riverside, CA in August 2004.

Experimental searches for exotic multiquark particles

1989 ◽  
Vol 67 (12) ◽  
pp. 1148-1152
Author(s):  
H. -W. Siebert
Keyword(s):  
Proton Beam ◽  
Neutron Beam ◽  
High Intensity ◽  
National Laboratory ◽  
Brookhaven National Laboratory ◽  
Inclusive Production ◽  
Missing Mass ◽  
Beam Experiment

Experimental searches for "exotic" multiquark hadrons are reported. In a hyperon beam experiment at the Organisation Européenne pour la Recherche Nucléaire-superproton synchrotron (CERN-SPS), evidence was found for narrow states at 3.1 GeV/c2, with charges + 1,0, and −1, decaying into Λ, [Formula: see text], and pions. Similar signals were also seen in a neutron beam experiment at Serpukhov. These states, called U (3100), are tentatively explained as [Formula: see text] systems, i.e., [Formula: see text]. Such states were proposed more than a decade ago. New hyperon beam experiments in preparation at CERN and Fermilab will study these states, provided they exist. The proposed multiquark systems H = uuddss and [Formula: see text] are also discussed. One candidate for the decay H(2175) → Σ−p was observed in a propane buble chamber exposed to a proton beam. At Brookhaven National Laboratory, a missing-mass experiment in a high-intensity K− beam will search for the H, and the new hyperon beam experiments will search for inclusive production of both H and P.

Chemical and orientational imaging of polymeric samples

1994 ◽  
Vol 52 ◽  
pp. 68-69
Author(s):  
H. Ade ◽  
B. Hsiao ◽  
G. Mitchell ◽  
E. Rightor ◽  
A. P. Smith ◽  
...  
Keyword(s):  
Ethylene Terephthalate ◽  
National Laboratory ◽  
Brookhaven National Laboratory ◽  
Carbonyl Groups ◽  
Aromatic Rings ◽  
Edge Structure ◽  
X Ray ◽  
Scanning Transmission ◽  
Polymeric Samples ◽  
X Ray Absorption

We have used the Scanning Transmission X-ray Microscope at beamline X1A (X1-STXM) at Brookhaven National Laboratory (BNL) to acquire high resolution, chemical and orientation sensitive images of polymeric samples as well as point spectra from 0.1 μm areas. This sensitivity is achieved by exploiting the X-ray Absorption Near Edge Structure (XANES) of the carbon K edge. One of the most illustrative example of the chemical sensitivity achievable is provided by images of a polycarbonate/pol(ethylene terephthalate) (70/30 PC/PET) blend. Contrast reversal at high overall contrast is observed between images acquired at 285.36 and 285.69 eV (Fig. 1). Contrast in these images is achieved by exploring subtle differences between resonances associated with the π bonds (sp hybridization) of the aromatic groups of each polymer. PET has a split peak associated with these aromatic groups, due to the proximity of its carbonyl groups to its aromatic rings, whereas PC has only a single peak.

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