A.S. Nikiforov

Measurement of the tensor analyzing power Ayy in inclusive breakup of 9 GeV/c deuterons on carbon at large transverse momenta of protons

Abstract The tensor analyzing power A yy in inclusive breakup of 9 GeV/c deuterons on carbon has been measured at the detected proton angle of 85 mr. The analyzing power remains positive at the highest measured momentum of the proton in definite contradiction with the predictions of the existing models. The vector analyzing power A y has been obtained simultaneously with A yy .

Tensor analyzing power T20 for cumulative pion production from deuterons in the GeV energy region

Abstract The tensor analyzing power T 20 for the reaction d ↑ + 12 C → π ± (0°) + X has been measured with a polarized deuteron beam from 6.2 to 9.0 GeV/ c at a pion momentum3.0 GeV/ c . This experiment is focused on “cumulatively produced pions”, which are produced beyond the kinematically allowed limit for free nucleon-nucleon collisions. The measured values of T 20 turn out to be close to zero. They are in disagreement with the results of our impulse approximation calculation which is based on a single NN → πNN interaction and takes into account the internal motion of nucleons in the deuteron. Possible explanations of the result are discussed.

An experimental run on the new superconducting accelerator Nuclotron at 3.8 and 6.2 GeV/c deuteron momemtum

Abstract The new superconducting accelerator Nuclotron have been operated for the first time at 3.8 and 6.2 GeV/c deuteron momentum and the run on the internal target have been carried out in March94. The various scintillation counters for ΔE-E and time-of-flight (TOF) measurements, the silicon and CsI(Tl) crystal detectors for ΔE-E measurements as well, and the lead glass EM calorimeters were used. The secondary particles γ, π, K, p, d, and t as well as He fragments produced by deuterons on the internal targets were detected and identified relaibly, thus manifestating a broad perspective of the relativistic nuclear physics research on Nuclotron in the nearest future.

First results on the tensor analyzing power Ayy in deuteron inclusive breakup at large transverse momenta of protons

The tensor analyzing power A yy in inclusive breakup of 9 GeV/c deuterons on carbon has been measured at 85 mrad of the detected proton angle using polarized beam of the Synchrophasotron of the Laboratory for High Energies of JINR. The analyzing power A yy remains positive at the highest measured momentum of the proton in definite contradiction with the predictions based on the standard nucleon-nucleon potentials.

Cross‐Fertilization between Spallation Neutron Source and Third Generation Synchrotron Radiation Detectors

Suffering presently from relatively low source strengths compared to synchrotron radiation investigations, neutron scattering methods will greatly benefit from the increase of instantaneous flux attained at the next generation of pulsed spallation neutron sources. In particular at ESS, the strongest projected source, the counting rate load on the detectors will rise by factors of up to 50–150 in comparison with present generic instruments. For these sources the detector requirements overlap partly with those for modern synchrotron radiation detectors as far as counting rate capability and two‐dimensional position resolution are concerned. In this paper, examples of the current and forthcoming detector development, comprising e.g. novel solutions for low‐pressure micro‐strip gas chamber detectors, for silicon micro‐strip detectors and for the related front‐end ASICs and data acquisition (DAQ) systems, are summarized, which will be of interest for detection of synchrotron radiation as well.

Measurement of the Tensor Analyzing Power T20 in the Fragmentation of 9 GeV Tensor Polarized Deuterons into Cumulative Pions

Tensor analyzing power T 20 of the reaction d ↑ A → π–(0°)X was measured in the fragmentation of 9 GeV deuterons into pions with momenta from 3.5 to 5.3 GeV/c on hydrogen, beryllium and carbon targets. This momentum range corresponds to the region of cumulative production with the cumulative variable x c from 1.08 to 1.76. The values of T 20 were found to be small and consistent with positive values in contradiction with the predictions based on a direct mechanism assuming N N collision between a high momentum nucleon in the deuteron and a target nucleon (N N → N N π).

Development of a data acquisition system for the SPHERE spectrometer

Abstract The 4π-detector SPHERE for studying multiple particle cumulative production is currently under construction at the Laboratory of High Energies, JINR, Dubna. This paper briefly describes the present status and future developments of the data acquisition system for this setup. A multiprocessor system based on VMEbus will be implemented for parallel readout, event-building, and data preprocessing. A workstation will be used for data analysis and experimental control. The investigation has been performed at the Laboratory of High Energies, JINR.