The super Pioneering High Energy Nuclear Interaction eXperiment (sPHENIX) at the Relativistic Heavy Ion Collider will perform high-precision measurements of jets and heavy flavor observables for a ...wide selection of nuclear collision systems, elucidating the microscopic nature of strongly interacting matter ranging from nucleons to the strongly coupled quark-gluon plasma. A prototype of the sPHENIX calorimeter system was tested at the Fermilab Test Beam Facility as experiment T-1044 in the spring of 2016. The electromagnetic calorimeter (EMCal) prototype is composed of scintillating fibers embedded in a mixture of tungsten powder and epoxy. The hadronic calorimeter (HCal) prototype is composed of tilted steel plates alternating with the plastic scintillator. Results of the test beam reveal the energy resolution for electrons in the EMCal is <inline-formula> <tex-math notation="LaTeX">2.8\%\oplus 15.5\%/\sqrt {E} </tex-math></inline-formula> and the energy resolution for hadrons in the combined EMCal plus HCal system is <inline-formula> <tex-math notation="LaTeX">13.5\%\oplus 64.9\%/\sqrt {E} </tex-math></inline-formula>. These results demonstrate that the performance of the proposed calorimeter system satisfies the sPHENIX specifications.
The superconducting inflector for the BNL g-2 experiment Yamamoto, A; Makida, Y; Tanaka, K ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2002, Letnik:
491, Številka:
1-2
Journal Article
Recenzirano
The muon g-2 experiment at Brookhaven National Laboratory (BNL) has the goal of determining the muon anomalous magnetic moment, aμ(=(g-2)/2), to the very high precision of 0.35 parts per million and ...thus requires a storage ring magnet with great stability and homogeneity. A super-ferric storage ring has been constructed in which the field is to be known to 0.1ppm. In addition, a new type of air core superconducting inflector has been developed and constructed, which successfully serves as the injection magnet. The injection magnet cancels the storage ring field, 1.5T, seen by the entering muon beam very close to the storage ring aperture. At the same time, it gives negligible influence to the knowledge of the uniform main magnetic field in the muon storage region located at just 23mm away from the beam channel. This was accomplished using a new double cosine theta design for the magnetic field which traps most of the return field, and then surrounding the magnet with a special superconducting sheet which traps the remaining return field. The magnet is operated using a warm-to-cold cryogenic cycle which avoids affecting the precision field of the storage ring. This article describes the design, research development, fabrication process, and final performance of this new type of superconducting magnet.
The STAR detector magnet subsystem Bergsma, F.; Blyth, C.O.; Brown, R.L. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2003, Letnik:
499, Številka:
2
Journal Article
Recenzirano
We describe the specification and design, construction and mapping of the STAR magnet. Measurements demonstrate that field quality exceeds specifications for uniformity and agrees with design values.
We study a two-dimensional theory of gravity coupled to matter that
is relevant to describe holographic properties of black holes with two
equal angular momenta in five dimensions (with or without ...cosmological
constant). We focus on the near-horizon geometry of the near-extremal
black hole, where the effective theory reduces to Jackiw-Teitelboim (JT)
gravity coupled to a massive scalar field. We compute the corrections to
correlation functions due to cubic interactions present in this theory.
A novel feature is that these corrections do not have a definite sign:
for AdS
_5
5
black holes the sign depends on the mass of the extremal solution. We
discuss possible interpretations of these corrections from a
gravitational and holographic perspective.
We also quantify the imprint of the JT sector on the UV region, i.e. how
these degrees of freedom, characteristic for the near-horizon region,
influence the asymptotically far region of the black hole. This gives an
interesting insight on how to interpret the IR modes in the context of
their UV completion, which depends on the environment that contains the
black hole.
The super Pioneering High Energy Nuclear Interaction eXperiment (sPHENIX) at the Relativistic Heavy Ion Collider (RHIC) will perform high precision measurements of jets and heavy flavor observables ...for a wide selection of nuclear collision systems, elucidating the microscopic nature of strongly interacting matter ranging from nucleons to the strongly coupled quark-gluon plasma. A prototype of the sPHENIX calorimeter system was tested at the Fermilab Test Beam Facility as experiment T-1044 in the spring of 2016. The electromagnetic calorimeter (EMCal) prototype is composed of scintillating fibers embedded in a mixture of tungsten powder and epoxy. The hadronic calorimeter (HCal) prototype is composed of tilted steel plates alternating with plastic scintillator. Results of the test beam reveal the energy resolution for electrons in the EMCal is \(2.8\%\oplus~15.5\%/\sqrt{E}\) and the energy resolution for hadrons in the combined EMCal plus HCal system is \(13.5\%\oplus 64.9\%/\sqrt{E}\). These results demonstrate that the performance of the proposed calorimeter system satisfies the sPHENIX specifications.
The AGS operates a varied program of proton, heavy ion, and polarized proton acceleration for fixed-target experiments and will soon serve as the injector of these beams into the Relativistic Heavy ...Ion Collider, RHIC. The new Booster synchrotron extends the range of intensities and masses that can be accelerated. The 1.5 GeV injection energy increases the space charge limit by a factor of four to more than 6 x 10/sup 13/ protons per pulse. To accommodate the increased beam current the RF system will be upgraded to provide more power and lower impedance to the beam. The flexibility of the RF system will also be enhanced by virtue of a new RF beam control system and installation of individual tuning servos for the ten RF cavities.< >
Overview of the ATR power supplies Bruno, D.; Soukas, A.; Toldo, F. ...
Proceedings of the 1997 Particle Accelerator Conference (Cat. No.97CH36167),
1997, Letnik:
3
Conference Proceeding
Odprti dostop
The AGS to RHIC transfer line (ATR) transports a variety of beams from the Alternating Gradient Synchrotron (AGS) which gets its input from the Booster Synchrotron. In turn, the Booster receives ...input beams from either a tandem Van de Graaff (heavy ions) or a linac (protons). The AGS extracts beam bunches, up to a rate of 30 Hertz, to the ATR which feeds the Relativistic Heavy Ion Collider (RHIC) starting with the sextant test in January of 1997. The ATR is made up of the upgraded U line and the new W, X and Y lines. A test in 1995 transported beam to the end of the W line. During normal operation, a pulsed switching magnet at the end of the W line will bend the beam into the X line or the Y line so that the two storage rings in RHIC are filled with counterrotating beams. The ATR line is comprised of 80 power supplies (PS's), 17 of which are upgraded AGS PS's. The remaining 63 PS's were newly purchased. These PS's range from bipolar 600 watt linear type trim magnet PS's to 1 Megawatt, thyristor, dipole PS's. Results of the commissioning runs will be presented, as well as descriptions of regulation, filtering, and analog and digital controls.
Investigations of headland sand bypassing are still an under-reported subject in the literature. This paper aims to understand the contribution of currents forced by different mechanisms such as ...tides, winds (i.e. local wind acting over the ocean surface generating currents, without considering wave generation) and waves (as they approach/break on the coast) to headland sand bypassing. The study was carried out in an area comprising a series of seven headlands with varying wave exposure due to changes in shoreline orientation and increasing tidal influence close to a relatively large bay. This paper uses a calibrated and validated process-based model (Delft3D) to simulate a series of scenarios including spring and neap tides during flood and ebb conditions and a range of wind and wave scenarios that encompass both average and extreme conditions. The results indicate that waves are the main driving force for the headland bypassing as they transport sand at rates two orders of magnitude higher than tide- or wind-driven sediment transport. The tide-driven currents can only transport sediment during spring tides in locations where the currents are intensified. It is also demonstrated that the wave direction plays an important role in sediment transport. In exposed areas with larger headlands a combination of wave directions is required to first transport sediment offshore (out of the beach) and secondly to transport sediment alongshore and back to the next beach. Whereas in areas with little variation in wave direction exposure, the same oblique wave direction is responsible for the entire headland bypassing process. This is the first time the contribution of tide-, winds- and wave-generated sediment transport to headland bypassing have been studied.
•Importance of different processes to headland sand bypassing was tested.•Representative scenarios were modeled.•Waves are the main driving force for headland bypassing.•Wave-forced transport is two orders of magnitude higher than other forcing.
A three-state model for the photo-Fries rearrangement (PFR) is proposed based on multiconfigurational calculations. It provides a comprehensive mechanistic picture of all steps of the reaction, from ...the photoabsorption to the final tautomerization. The three states participating in the PFR are an aromatic
ππ*, which absorbs the radiation; a pre-dissociative
nπ*, which transfers the energy to the dissociative region; and a
πσ*, along which dissociation occurs. The transfer from
ππ* to
nπ* involves pyramidalization of the carbonyl carbon, while transfer from
nπ* to
πσ* takes place through CO stretching. Different products are available after a conical intersection with the ground state. Among them is a recombined radical intermediate, which can yield ortho-PFR products after an intramolecular 1,3-H tunneling. The three-state model is developed for phenyl acetate, the basic prototype for the PFR, and it reconciles the theory with a series of observations from time-resolved spectroscopy. It also delivers a rational way to optimize PFR yields, since, as shown for four different systems, diverse substituents can change the energetic order of the
ππ* and
nπ* states, preventing or enhancing the PFR.
Acute myocardial infarction (AMI) initiates an intense inflammatory response that promotes cardiac dysfunction, cell death, and ventricular remodeling. The molecular events underlying this ...inflammatory response, however, are incompletely understood. In experimental models of sterile inflammation, ATP released from dying cells triggers, through activation of the purinergic P2X7 receptor, the formation of the inflammasome, a multiprotein complex necessary for caspase-1 activation and amplification of the inflammatory response. Here we describe the presence of the inflammasome in the heart in an experimental mouse model of AMI as evidenced by increased caspase-1 activity and cytoplasmic aggregates of the three components of the inflammasome—apoptosis speck-like protein containing a caspase-recruitment domain (ASC), cryopyrin, and caspase-1, localized to the granulation tissue and cardiomyocytes bordering the infarct. Cultured adult murine cardiomyocytes also showed the inducible formation of the inflammasome associated with increased cell death. P2X7 and cryopyrin inhibition (using silencing RNA or a pharmacologic inhibitor) prevented the formation of the inflammasome and limited infarct size and cardiac enlargement after AMI. The formation of the inflammasome in the mouse heart during AMI causes additional loss of functional myocardium, leading to heart failure. Modulation of the inflammasome may therefore represent a unique therapeutic strategy to limit cell death and prevent heart failure after AMI.
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