Neutral Kaon Femtoscopy in STAR Pawłowska, D.
Physics of particles and nuclei,
05/2020, Letnik:
51, Številka:
3
Journal Article
Recenzirano
Properties of nuclear matter can be studied by relativistic heavy-ion collisions in high-energy experiments like STAR. One of the methods to learn about properties of nuclear matter is femtoscopy, ...which relies on information carried by particles produced in the collisions. Using femtoscopic observables, space-time characteristics of the source can be extracted. During heavy-ion collisions mostly pions are produced, and therefore pion femtoscopy is a particularly useful tool. High statistics data sets from RHIC have also made it possible to study the strange particle correlations. The lightest strange hadrons are charged and neutral kaons. The strong interaction, which conserves the strangeness quantum number, is responsible for the kaon production. It is possible to study the neutral kaons,
, which can be measured through their decay products to charged pions. In these proceedings, one-dimensional correlation functions of neutral kaon pairs in Au + Au collisions at
= 200 GeV measured by the STAR experiment at RHIC are presented.
The amount of data coming from modern acquisition systems, especially working in extreme experimental conditions, is significantly rising over the years. Combined with complex algorithms, the ...computation time and power consumption are considerably increasing. The issue usually occurs in many world laboratories, such as CERN, Brookhaven National Laboratory, GSI Helmholtzzentrum für Schwerionenforschung, and tokamak devices (JET, WEST, MAST, and more). Often well verified, but legacy codes are used as a main computational engine, resulting in weak performance unsuitable for current needs. The paper presents a methodology to appropriately adapt the legacy C/C++ high-energy physics (HEP) algorithms for computation acceleration using FPGAs, which may improve the designing of real-time systems based on verified codes. The main idea is to separate the HLS-FPGA code work areas between groups of experts: physicists and electronics. The methodology consists of several parts: interfacing, storage, verification methods, defining the algorithm and data structures, program refactoring in the scope of CPU and FPGA, performance and results analysis, FPGA verification methods, FPGA performance estimation, and automatization of the process. The methodology has been successfully tested by implementing a legacy, complex HEP algorithm for femtoscopy correlations in the HLS framework for FPGA. It works with extensive input data from international experiments, like STAR at RHIC. The implementation and verification were done successfully on the FPGA hardware platform. Following the methodology results in a clearer to analyze and debug HEP code than a machine-generated version by tools. We also confirmed that it is possible to make a working, HLS-compliant program designed by non-FPGA experts. Using the modern implementation tools, FPGA resource usage is low despite unoptimized syntax. It gives a large field for further significant optimizations and good performance. The proposed approach should be interesting to introduce in devices like tokamaks, synchrotrons, and similar, where the real-time monitoring of the experimental processes is essential.
•Methodology for complex algorithm conversion from legacy code to hardware accelerated in FPGA in high level synthesis (HLS) languages.•Guidelines to achieve the performance improvement of legacy (C, Fortran etc.) high energy physics algorithms.•Discussion about the pros and cons of using the high-level synthesis (HLS) languages for acceleration.•Preliminary in-hardware FPGA laboratory tests of the presented approach based on Monte-Carlo HEP algorithm for heavy-ion collisions.•Use for high energy physics experiments, however not limited to.
The purification of pre-concentrated up to 80 wt.% H
3PO
4 phosphoric acid (PA) obtained from Kola apatite in one of the Polish plants by the wet processing route was carried out by sulphate ...precipitation, desorption of volatile components (SiF
4, HF) and liquid–liquid extraction method using 4-methyl-2-pentanone (MIBK). The experiment was carried out on a laboratory scale. The effects of the reagent grade Ca(H
2PO
4)
2 · H
2O, CaHPO
4 · 2H
2O, Ca
3(PO
4)
2, and technical grade calcium oxide, the molar ratio of Ca
2+ to SO
4
2− (0.8–1.5), the temperature (343–363 K), and the duration of precipitation time (1800–7200 s) on the extent of purification from SO
4
2− were determined. The most efficient precipitant was CaHPO
4 · 2H
2O. The precipitation using CaHPO
4 · 2H
2O purified phosphoric acid from the initial SO
4
2− concentration (1.5–1.8%) to a level of 0.1–0.2 wt.%. The use of 100% excess of SiO
2 over the stoichiometric ratio (in relation to SiF
4), while air bubbling and very intensive stirring of the phosphoric acid at 403 K was carried out, allowed the fluorine concentration to decrease to a level below 0.005 wt.% of F. Purification from metals was carried out at room temperature using 1:1.22 mass ratio of PA to MIBK. The stripped phosphoric acid, with a concentration of about 50 wt.% of H
3PO
4 and 1.5 wt.% of MIBK, contained Fe and Al at a level of 0.01–0.005 wt.% each, Pb, Th <1 ppm, Cr, Co, Ni <0.1 ppm, As, Cd—not detected.
An x‐ray diffraction method (XRD) for quantitative determination of the crystalline Na5P3O10‐I (Form‐I) in a mixture of Form‐I/Form‐II was applied for commercial pentasodium tripolyphosphate ...analysis. The XRD pattern of the Form‐I shows the unique non‐overlapping 2θ peak at a position of ≈ 21.8 deg. and also at ≈ 29.0 deg. (Cu radiation). The area (integral of the intensity) under the peaks is proportional to the amount of the Form‐I in the mixture covering the range up to 100 wt.%. That enables one to obtain a calibration line and to determine the amount of Form‐I in the mixture of Form‐I/Form‐II and also in commercial pentasodium tripolyphosphate.
Commercial samples with high Form‐I concentration, in case they are contaminated with sodium pyrophosphate (Na4P2O7), should be diluted with Form‐II to bring the concentration of the Form‐I below 50 wt.% in the analysed sample.
There appears to be increasing evidence that ethanol toxicity may be associated with an increased production of reactive oxygen intermediates. In rats we studied the effect of 4 weeks of ethanol ...ingestion on the liver cytosolic defense system against active oxygen species. Compared with the control rats, the ethanol-fed animals had a significantly higher liver malondialdehyde content and significantly lower reduced glutathione level. Moreover, ethanol feeding resulted in a decrease of superoxide dismutase and catalase activities while glutathione peroxidase activity was only slightly diminished. Thus, prolonged ethanol administration profoundly modified the hepatic status of the enzymatic defense system leading to lipid peroxidation that may disrupt vital functions of liver cells.
This study examined the effect of increases in renal interstitial hydrostatic pressure (PI) on sodium excretion (UNaV) utilizing a direct technique for increasing renal interstitial volume. PI was ...increased by renal interstitial volume expansion (RIVE) via injection of 50 microliters of a 2% albumin in saline solution into the renal interstitium through a chronically implanted interstitial catheter. RIVE resulted in a stable increase in PI (4.6 +/- 0.4 to 9.4 +/- 0.8 mmHg) that was sustained over a 30- to 40-min period without significant changes in renal blood flow or glomerular filtration rate. Increases in PI were associated with significant increases in urine flow (13.8 +/- 3.4 to 31.7 +/- 5.0 microliters/min) and UNaV (2.3 +/- 0.6 to 6.2 +/- 1.1 micro eq/min) and fractional excretion of Na (2.6 +/- 0.8 to 6.9 +/- 1.5%). To determine the importance of albumin in maintaining an elevated PI, the effects of renal interstitial injections of saline were compared with albumin in saline solution. Injection of 50 microliters of saline into the renal interstitium had no sustained effect on PI. Injection of 2% albumin in saline solution in the same group of rats resulted in significant elevations in PI and UNaV. These data indicate that direct increases in PI via renal interstitial volume expansion result in significant increases in UNaV, thus supporting a role for PI in controlling UNaV.
This study was designed to investigate the hemodynamic effects of exogenous adenosine in the interstitium of the rat kidney. Adenosine or its analogues were infused into the renal interstitium by ...means of chronically implanted capsules. Infusion of adenosine (bolus 0.5 mumol plus 0.1 mumol/min) decreased glomerular filtration rate (GFR) from 0.81 +/- 0.06 (mean +/- SE) to 0.37 +/- 0.06 ml/min while having no effect on renal blood flow (RBF). The metabolically stable analogue, 2-chloradenosine (2-ClAdo), (bolus 10 nmol plus 2 nmol/min) decreased GFR from 0.73 +/- 0.07 to 0.21 +/- 0.06 ml/min. Interstitial infusion of theophylline, an adenosine receptor antagonist, completely abolished the effects of adenosine and 2-ClAdo on GFR. The distribution of adenosine, when infused into the renal interstitium, was determined using radiolabeled 5'-(N-ethyl)-carboxamidoadenosine (NECA), a metabolically stable adenosine agonist. After continuous infusion, 3HNECA was distributed throughout the kidney. The effects of NECA to reduce GFR were similar to those of adenosine and 2-ClAdo. We conclude that increased levels of adenosine in the renal interstitium markedly decrease GFR without affecting RBF in steady-state conditions. The marked effects of adenosine agonists during their infusion into the renal interstitium and the complete blockade of these effects by theophylline suggest an extracellular action of adenosine.
