S. G. Reznikov

ΔE-E detector for proton registration in nonmesonic deuteron breakup at the Nuclotron internal target

A design for a ΔE-E detector to investigate deuteron breakup in the Nuclotron-M internal target in a deuteron energy interval of 300–500 MeV is presented. The high-voltage power supply system of the PMT-63, which is based on the computer-controlled Wenzel Electronik module, is briefly described. A light-emitting diode (LED) monitoring system for the ΔE-E detector is considered. The results of testing the ΔE-E detector using cosmic muons and deuteron beams of the Nuclotron are presented.

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 .

Proposal on the measurements of d–p elastic scattering analyzing powers at 0.3–2.0 GeV at the Internal Target Station of the Nuclotron

A new high-energy beam polarimeter is proposed for Nuclotron, which uses the Internal Target Station (ITS). This polarimeter based on a measurement of asymmetry for the d–p elastic scattering will allow one to measure simultaneously both vector and tensor components of deuteron beam polarization. For this purpose an analyzing powers measurement for the d–p elastic scattering at energies T d = 0.88–2 GeV is proposed. The precise measurements of the deuteron analyzing powers over the energy range T d = 300–2000 MeV can give an irreplaceable clue to the study of the spin dependence of three nucleon forces.

Measurement of the vector and tensor analyzing powers for dp-elastic scattering at 880 MeV

The vectorAy and tensor analyzing powers Ayy andAxx for dpelastic scattering were measured at T lab d = 880 MeV over the c.m. angular range from 60 ◦ to 140 at the JINR Nuclotron. The data are compared with prediction s of different theoretical models based on the use of nucleon-nucleon forces only. The observed disc repancies of the measured analyzing powers from the calcula tions require the consideration of additional mechanisms. PACS: 24.70.+s, 25.10. +s, 21.45. +v

A Resonance structure in the gamma gamma invariant mass spectrum in pC- and dC-interactions

Along with {pi}{sup 0} and {eta} mesons, a resonance structure in the invariant mass spectrum of two photons at M{sub {gamma}}{sub {gamma}}=360{+-}7{+-}9 MeV is observed in the reaction dC{yields}{gamma}+{gamma}+X at momentum 2.75 GeV/c per nucleon. Estimates of its width and production cross section are {gamma}=63.7{+-}17.8 MeV and {sigma}{sub {gamma}}{sub {gamma}}=98{+-}24{sub -67}{sup +93} {mu}b, respectively. The collected statistics amount to 2339{+-}340 events of 1.5x10{sup 6} triggered interactions of a total number {approx}10{sup 12} of dC interactions. This resonance structure is not observed in pC collisions at the beam momentum 5.5 GeV/c. Possible mechanisms of this ABC-like effect are discussed.

Resonance structure in theγγinvariant mass spectrum inpC anddC interactions

Along with {pi}{sup 0} and {eta} mesons, a resonance structure in the invariant mass spectrum of two photons at M{sub {gamma}}{sub {gamma}}=360{+-}7{+-}9 MeV is observed in the reaction dC{yields}{gamma}+{gamma}+X at momentum 2.75 GeV/c per nucleon. Estimates of its width and production cross section are {gamma}=63.7{+-}17.8 MeV and {sigma}{sub {gamma}}{sub {gamma}}=98{+-}24{sub -67}{sup +93} {mu}b, respectively. The collected statistics amount to 2339{+-}340 events of 1.5x10{sup 6} triggered interactions of a total number {approx}10{sup 12} of dC interactions. This resonance structure is not observed in pC collisions at the beam momentum 5.5 GeV/c. Possible mechanisms of this ABC-like effect are discussed.

The 270 MeV deuteron beam polarimeter at the Nuclotron Internal Target Station

A deuteron beam polarimeter has been constructed at the Internal Target Station at the Nuclotron of JINR. The polarimeter is based on spin-asymmetry measurements in the d − p elastic scattering at large angles and the deuteron kinetic energy of 270 MeV. It allows to measure vector and tensor components of the deuteron beam polarization simultaneously.

Investigation of the angular dependence of the analyzing powers in the deuteron-proton elastic scattering at the nuclotron

New polarimeter based on the asymmetry measurement in dp-elastic scattering has been constructed at internal target at Nuclotron (JINR). The result on the deuteron analyzing powers Ay, Ayy and Axx in the deuteron-proton (dp) elastic scattering at the energies of 880 and 2000 MeV are presented. They are compared with different theoretical approaches.

Analyzing powers Ayy , Axx , Axz and Ay in the dd → 3Hen reaction at 270 MeV

The data on the tensor Ayy, Axx, Axz and vector Ay analyzing powers in the dd → Hen obtained at Td = 270 MeV in the angular range 0 ◦ – 110◦ in the c.m. are presented. The observed negative sign of the tensor analyzing powers Ayy, Axx and Axz at small angles clearly demonstrate the sensitivity to the ratio of the D and S wave component of the He wave function. However, the one-nucleon exchange calculations by using the standard He wave functions have failed to reproduce the strong variation of the tensor analyzing powers as a function of the angle in the c.m. PACS. 24.70.+s Polarization phenomena in reactions – 25.10.+s Nuclear reactions involving few-nucleon system – 21.45.+v Few-body systems

MRS silicon avalanche detectors with negative feedback for time-of-flight systems

Investigation of time characteristics of silicon avalanche detectors with negative feedback based on Metal-Resistive layer-Semiconductor structure, proposed for Time-of-Flight systems, is described in this paper. Time resolutions of 550 ps on β-electrons and 250 ps on LED light pulses were obtained. Design and principles of operation are described briefly.