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Deuteron beam polarimeter at Nuclotron internal target

Deuteron beam polarimeter at Nuclotron internal target

Deuteron beam polarimeter [4] is placed in the Nuclotron ring. It consists of a spherical scattering chamber and target change system that can set six di ff erent targets. A detector sup- port with 39 mounted plastic scintillation counters is placed downstream the ITS spherical chamber. Each plastic scintillation counter was coupled to a photo-multiplier tube Hama- matsu H7416MOD. Eight proton detectors were installed for the left arm, similar – for the right and upper ones, but due to the space limitation – only four for the lower arm.

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Deuteron beam polarization measurement at 270 MeV at Nuclotron internal target

Deuteron beam polarization measurement at 270 MeV at Nuclotron internal target

Deuteron beam polarimeter [4] consists of a spherical scattering chamber and system change six different targets placed in the Nuclotron ring. A detector support with 39 mounted plastic scintillation counters coupled to the Hamamatsu H7416MOD photo- multiplier tubes is placed downstream the ITS spherical chamber. Eight proton detectors were installed for left, as well as for right and up, but due to space limitation – only four for down. The angular spin of one proton detector was 2º in the laboratory frame, which corresponds to ∼4º in the c.m.s. Three deuteron detectors are placed at scattering angles of deuterons coinciding kinematically with the protons. Only one deuteron detector can cover the solid angle corresponding to four proton detectors placed down. In addition, one pair of detectors is placed to register two protons from quasi-elastic p−p scattering at θ pp =90º in the c.m.s. in the horizontal plane. The scattered deuterons and recoil protons at 270 MeV were detected in kinematic coincidence over the c.m.s. angular range of 65–135º at eight different angles, defined by the positions of the proton detectors.
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Investigation of reactions using polarized and unpolarized deuteron beam at Nuclotron: current status and perspectives

Investigation of reactions using polarized and unpolarized deuteron beam at Nuclotron: current status and perspectives

The dp → ppn breakup reaction is investigated by ΔE − E scintillation detectors. The deuteron energies are 0.3, 0.4 and 0.5 GeV. Up to eight ΔE − E detectors can be used in experiment. Each detector consists of thin and thick scintillator. Both scintillators are of a tube shape, the thin one of a height of 1 cm, the thick one of a 20 cm height, with the diameter of the cross section 8 cm and 10 cm, respectively. Two Photomultiplier tubes PMTs-85 are positioned opposite to each other at the outside cylindrical surface of the thin scintillator. At the bottom end of the E scintillator a photomultiplier tube PMT-63 is positioned. Solid angle of each of detector is 4 . 6 ◦ . The details of the ΔE − E detector construction can be found in [20]. Energy spectra and missing mass distributions of dp breakup reaction were compared with GEANT4 simulation [21]. Reasonable agreement gives us opportunity to handle the signal and background in more precise way. The GEANT4 modelling also confirms that energy losses and scattering angles of the particles which passed through the spherical steel hull that surrounds the target are relatively small except of region of very low energy up to 20 MeV. But protons with this energy energy are cut by coincidence condition of ΔE − E detector.
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The differential cross section for dp-elastic scattering at 500-900 MeV/n and large transverse momenta

The differential cross section for dp-elastic scattering at 500-900 MeV/n and large transverse momenta

In recent years the experiments to study d p-elastic scattering were performed at the Inter- nal Target Station (ITS) [25] at the JINR Nuclotron in the framework of DSS (Deuteron Spin Structure) project. The data for the differential cross section at 650, 700 [26] and 1000 MeV/n [27] were obtained. In this paper the angular dependences of the differential cross section for dp-elastic scattering at 500, 750 and 900 MeV/n, obtained at Internal Target Station (ITS) at the Nuclotron are presented.

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Drift chambers in BM@N Experiment

Drift chambers in BM@N Experiment

BM@N (Baryonic Matter at Nuclotron) [1] is a fixed target experiment at the JINR NICA-Nuclotron complex proposed to study the hot compressed nuclear matter produced in collisions of relativistic heavy nuclei with emphasis on strange matter production. The detailed description comprising both the physical goals and the experimental apparatus of BM@N experiment can be found in [1, 2] or [3]. The outer tracker including two identical drift chambers DCH1 and DCH2 [3, 4] is placed outside the magnetic field of SP41 dipole magnet [5]. Each DCH consists of four segments measuring different track coordinates in a transverse plane relative to the beam axis. The measured coordinates are y,x,u,v where u and v are y coordinates rotated by angles ±45 ◦ around z axis. Actually, the directly measured experimental observables are the electron drift times that are subsequently by the proper calibration technique [3, 6–8] converted to the distances of closest approach (DCA) of tracks to the anode wires. The typical drift time spectrum for the BM@N deuteron beam data along with the corresponding radius-time (or r – t ) calibration curve is shown in figure 1. Once the y,x,u,v coordinates are calculated using the DCAs provided by the calibration, the missing transverse coordinates in all the DCH planes are evaluated by solving the set of linear equations as described in [3]. Finally, the track candidates from both the drift chambers are combined and fitted by straight lines to produce the global track candidates.
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Photon and π0 pairs production in proton-nucleus and deuteron-nucleus interactions. Results of experiments on internal beams of the Nuclotron

Photon and π0 pairs production in proton-nucleus and deuteron-nucleus interactions. Results of experiments on internal beams of the Nuclotron

analysis we have used the data obtained on an internal beam of deuterons with momentum 2.75 GeV/c per nucleon [5]. The internal target consists of carbon wires with the diameter of 8 microns mounted in a rotatable frame. The overall construction is located in the vacuum shell of the accelerator. The duration of the irradiation cycle is 1 s. For the analysis, the data collected at the maximum beam intensity ( ∼ 10 9 per pulse), were selected (about 2 / 3 of all the data in the reaction d(2.0 GeV / n) + C

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Study of the deuteron analyzing powers in dp elastic scattering at the energy of 800 MeV

Study of the deuteron analyzing powers in dp elastic scattering at the energy of 800 MeV

MeV are presented. The measurements have been performed on Internal Tar- get Station of the JINR Nuclotron using polarized deuteron beam from new source of polarized ions. The experimental data are compared with the prelim- inary calculations obtained within framework of relativistic multiple scattering approach.

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VME–based DAQ system for the Deuteron Spin Structure setup at the Nuclotron internal target station

VME–based DAQ system for the Deuteron Spin Structure setup at the Nuclotron internal target station

Acknowledgments. The author has the pleasure to thank V.P.Ladygin for initiation of the polarization calculations development for DSS setup, S.G.Reznikov — for fruitful dis- cussions about VME hardware, and all the DSS collaboration — for permanent support and assistance. The author is grateful to V.V.Fimushkin, A.S.Belov, A.V.Butenko, and all the SPI and Nuclotron teams for cooperation during the runs. The present work could not be done without background provided by LHEP NOAFI team.

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Energy and target material dependence of the neutron yield induced by proton and deuteron bombardment

Energy and target material dependence of the neutron yield induced by proton and deuteron bombardment

The cross section for neutron production for a specific ion type at an energy E and a given target element are given in the TENDL data library [11], the ENDF data library [12] or can be calculated using the TALYS nuclear code [13]. The corresponding penetration range for a given energy interval dE can be calculated using the SRIM 2013 toolkit [14]. A python program to calculate the neutron yield was written and uploaded to a GitHub server [15]. The following analysis was done using the TALYS nuclear code using the default parameters as cross sections for all elements can be calculated. The neutron yield was calculated for the natural abundance and a full stop of the ions inside the target material.
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Experimental Investigation on Internal Strengthening of RC Beam with Transverse Circular Opening in Centre of L/3 Zone

Experimental Investigation on Internal Strengthening of RC Beam with Transverse Circular Opening in Centre of L/3 Zone

In the present experimental work was carried out with the Comparison of solid normal reinforced beam, un strengthened reinforced hallow circular reinforced beam & strengthened beam having reinforcement at 45° bent up over the hallow circular reinforced beam. All tests were conducted on the rectangular cross section beam of dimensions 150mm width &200mm depth & overall length of 1700mm. The length of the opening for the beam (0.40 times of depth) is 80mm. The opening located in L/3 zone of the beam at one end. Each beam of 3 samples was casted & tested.flexural strength on these beams are carried out under two point loading condition.
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Hard x-ray polarimeter for gamma-ray bursts and solar flares

Hard x-ray polarimeter for gamma-ray bursts and solar flares

One common feature of many GRB models is that the energy release takes the form of jets that are directed along the rotation axis of the system. Several indirect arguments have been used to argue that such jets are required to explain the observations. 3–5 Since the energy budget of a given GRB depends heaviliy on assumptions about the extent to which the flow is jet-like, determining the reality and nature of jets in GRBs is becoming an important goal of future observations. The observation of optical polarization in GRB afterglows, such as that for GRB990510 6 has provided direct evidence for geometrical beaming of emission related to the external shocks. Although the measured level of optical polarization is small (∼ 2%), several models predict levels of polarization as high as 10 or 20%, depending on the angle between the observer and the jet axis. 5, 7–9 Optical polarization measurements, and the theoretical studies that have been motivated by such measurements, have provided a better insight into the nature of the GRB phenomena. The optical studies, however, probe only the external shock region. In the context of the canonical fireball model, measurements of the hard X-ray polarization during the prompt phase of the GRB promise to provide a similar probe of the internal shock region. Since the outgoing flow at the internal shock is expected to be more tightly collimated than the flow at the external shock (resulting from a continuous spreading of the jet as it progresses outward through the fireball), one can perhaps expect a somewhat higher level of hard X-ray polarization during the prompt phase of the GRB. Both inverse Compton and synchrotron emission have been proposed as viable emission mechanisms for GRBs. The spectral signatures of these two processes can be very similar, so it is very difficult to determine the responsible mechanism on the basis of spectral measurements alone. Energy- dependent polarization measurements, in principle, offer a possible solution. The degree of linear polarization of synchrotron emission, unlike inverse Compton emission, is independent of energy. This energy-dependence of the polarization (or lack thereof)may therefore be exploited as a means of identifying the emission mechanism responsible for the hard X-ray and γ-ray emission.
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BM@N and MPD experiments at NICA

BM@N and MPD experiments at NICA

A schematic view of the BM@N set-up is shown in Fig. 5. The tracking system is based on 12 planes of GEM detectors installed inside the gap of the dipole magnet of 0.8 T (SP-41) and drift/pad detectors (DCH, CPC) situated outside the magnet. The fully equipped set-up contains two stations of the Time of Flight (TOF) system, a Zero Degree Calorimeter (ZDC), a Recoil detector, and 4 stations of a Silicon Tracker (ST) installed just downstream the target. Several milestones are foreseen to put in operation the fully equipped detector. The first physical run is planed before the end of 2017 with about a half of the GEM chambers installed, and the complete design configuration is foreseen to be operational in 2020. The BM@N research program is aimed at studying elementary and heavy ion collision with the beam kinetic energy covering the region from 3.5 to 4.5 GeV/n. The results of extensive feasibility studies indicate a good performance of the detector in reconstruction of cascades and hypernuclei (see Fig. 6) with a monthly rate of about 10 7 for each species.
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Early Results from the Qweak Experiment

Early Results from the Qweak Experiment

After statistics, the next largest contribution to the uncertainty on the asymmetry is expected to come from the determination of the beam polarization. An existing Møller polarimeter [13] routinely pro- vides percent-level precision in JLab’s Hall C. The polarimeter makes use of known analyzing powers provided by a fully polarized iron foil in a 3.5 T field. However, the measurement is invasive to the main experiment, and can only be performed at low beam currents. Therefore, a new Compton polarimeter was built for this experiment to complement the Møller polarimeter with a continuous, non-invasive and high current 1% / hour device. A circularly polarized green laser in a low gain cavity provides the known analyzing power. The agreement between the two polarimeters is well within their uncertainties.
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Time Dependent Studies on the Energy Gain of D-T Fuel Using Determination of Total Energy Deposited of Deuteron Beam in Hot Spot

Time Dependent Studies on the Energy Gain of D-T Fuel Using Determination of Total Energy Deposited of Deuteron Beam in Hot Spot

The fast-ignition concept has been described thoroughly in literature as one alternative to direct-drive hot-spot ignition. In this scheme a high-energy, high-intensity laser is used to compress a cold shell containing fusion fuel to high areal densities. A short-pulse, ultrahigh-intensity laser is then used to generate megavolt electrons to heat the core of the dense fuel assembly in a time that is short compared to hydrodynamic time scales. The use of two independent laser drivers to compress the fuel assembly and subsequently heat the core allows for higher target gains, in principle, for the same amount of driver energy. This is because high fuel-areal-density cores can be assembled with slow implosion velocities and ignition is achieved by efficiently coupling the short-pulse beam energy to the dense core. In comparison to conventional hot-spot ignition, the symmetry requirement of the fuel assembly in fast ignition is not as stringent; this relaxes the illumination uniformity and power-balance constraints of the driver.
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The SPIDER CMB Polarimeter

The SPIDER CMB Polarimeter

Bolometers and HEMT amplifiers have long played central roles in instrumentation for CMB science. Spider benefits from decades of bolometer technology development ( § 3.1). The most important innovations bringing Spider ’s B-mode science goals within reach are new detector and readout technologies that have enabled a dramatic increase in pixel counts. De- tector tiles combine polarized beam-forming elements (slot antenna arrays), band-defining (LC microstrip) filters, and bolometers on a single substrate ( § 3.2). All of these com- ponents are fabricated for hundreds of devices at a time in an entirely photolithographic process ( § 3.3). Voltage-biasing superconducting bolometers in the steep transition between their superconducting and normal states establishes an electrothermal feedback mechanism that greatly increases their speed ( § 3.4). This enables time-domain multiplexed readout using cryogenic SQUID amplifiers coupled with multichannel warm electronics ( § 3.5).
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Study of neutron spectra in extended uranium target. New experimental data

Study of neutron spectra in extended uranium target. New experimental data

The use of proton beams for energy production in accelerator-driven systems (ADS) was exten- sively investigated [1]-[3] and the general opinion is that the optimal energy of proton beam lies in the range 1-3 GeV. The possibility to use heavy-ion beams for ADS was less analyzed and the conclusions of authors are contradictory [4]-[5]. Simulations performed using the code Geant4 in a quasi-infinite uranium target predict that one cannot improve the energetic efficiency of proton or deuteron beams by increasing the beam energy above 2-3 AGeV, but one can get a higher efficiency by accelerating heavier ions [6]. Based on this fact, a series of experiments with ion beams started at JINR. A more detailed analysis of particle distributions and spectra was realized by measuring the accumulation rates of isotopes with threshold energies from 0 to 70 MeV, using probes of 59 Co placed at different
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Active echolocation beam focusing in the false killer whale, Pseudorca crassidens

Active echolocation beam focusing in the false killer whale, Pseudorca crassidens

The diameter of the posterior portion of the false killer whale skull is approximately 30cm (Cowley, 1944) and the wavelength of this species’ echolocation signals is approximately 5cm (Kloepper et al., 2010a). Although there are no published data on the curvature of the Pseudorca skull, it is clearly concave (Fig.6). Thus, assuming that the skull and air sacs reflect the pulses generated in the MLDB complex, the morphology of a false killer whale’s sound-generating apparatus might be modeled as a focused radiator that creates a region of very narrow beamwidth at a certain distance from the source (O’Neil, 1949; Chen et al., 1993). Of course, such a simplified model assumes a homogenous volume within the concavity and does not account for the muscles, tissue and acoustic fats that comprise the odontocete forehead and may further modify the echolocation beam. The shape and properties of the melon may act similarly to an optical biconvex lens to further focus the echolocation beam (Keating, 2002), and this focusing may be changed by the muscles surrounding the melon, which are hypothesized to change its shape (Harper et al., 2008).
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Results on longitudinal spin physics at COMPASS

Results on longitudinal spin physics at COMPASS

to the total spin of the nucleon are determined to be in the range of 0.26 < ΔΣ < 0.36. The COMPASS data taken on the proton and deuteron target are combined to extract the non-singlet structure function, which is used to verify the Bjorken sum rule. The obtained ratio of the weak coupling constants is | g A /g V | = 1.22 ± 0.05 ± 0.10 is obtained, which verifies the sum rule within an accuracy of 9%. A dedicated measurement of the gluon polarisation has been performed using p T dependent muon-

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Determination of the proton spin structure functions for 0.05 < Q(2)  < 5GeV(2) using CLAS

Determination of the proton spin structure functions for 0.05 < Q(2)  < 5GeV(2) using CLAS

with again the same proportionality constant assumed. The inelastic scattering model employed Fermi-smeared cross sections calculated for each nucleus [104], which included (unpolarized) radiative corrections and corrections for the nuclear EMC effect. Free proton cross sections were calculated from a fit to world data for F 1 p and F 2 p [105]. For cross sections on heavier nuclei, a Fermi convolution of the smearing of free nucleon Born cross sections was fit to inclusive scattering data, including EG1b data from 12 C, solid 15 N, and empty (LHe) targets [106]. The nuclear EMC effect was parameterized using SLAC data [107]. Radiative corrections used the treatment of Mo and Tsai [108]; ex- ternal Bremsstrahlung probabilities incorporated all material thicknesses in CLAS from the target vertex through the inner layer DC. Radiated cross sections (relative to that of 12 C) were calculated for each target material for radiation length fractions 0.01X 0 and 0.02X 0 , and were linearly interpolated
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γ-ray generation enhancement by the charge separation field in laser-target interaction in the radiation dominated regime

γ-ray generation enhancement by the charge separation field in laser-target interaction in the radiation dominated regime

The paper is organized as follows. Section II briefly gathers three fundamental points: an analysis of the electron equation of motion, a comment on the role of the electro- static field, and an analysis on the synchrotron radiation. Section III is devoted to the numerical approach where the synchrotron radiation computation algorithm is described and the simulation parameters are given. Sections IV–VII are devoted to studies of various regimes of laser plasma interaction. Section IV describes the dependence of the laser absorption on the target thickness. Section V is devoted to studies of the influence of the charge separation field on elec- tron acceleration and conditions of the intense radiation production. Section VI considers several setups of practical interest where the charge separation field has a significant influence on radiation emission. The temporal and spatial behavior is analyzed and the emitted radiation is studied by variation of the laser polarization, the target thickness, and the ion mass. Finally in Sec. VII, the validity of the classical approach is proved in comparisons with the quantum electro- dynamics (QED) Monte Carlo modelling. 21
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