Measurements of spin rotation parameter A in pion-proton elastic scattering at 1.62 GeV/c

The ITEP-PNPI collaboration presents the results of the measurements of the spin rotation parameter A in the elastic scattering of positive and negative pions on protons at P_beam = 1.62 GeV/c. The setup included a longitudinally-polarized proton target with superconductive magnet, multiwire spark chambers and a carbon polarimeter with thick filter. Results are compared to the predictions of partial wave analyses. The experiment was performed at the ITEP proton synchrotron, Moscow.Comment: 7 pages, 3 figures. To be published in Phys. Lett.

Development and improvement of switching stands of high-voltage LUE modulators

The results of the development, operation and improvements of switch racks are presented. Particular attention is paid to the control and protection systems of both the thyratrons themselves and the control units of the switches. The main characteristics and the degree of reliability of switching racks and thyratrons of various types are compared. The development and implementation of switching racks based on six types of thyratrons was carried out: TGI1-1000/25, TGI1-2500/35, TGI1-5000/50, TGI1-5k/50 (Russia), TGI1-2500/50 (Ukraine) and CX 1525 A (England).Представлено результати розробок, експлуатації та удосконалень комутаційних стойок. Особливу увагу приділено системам контролю і захисту як самих тиратронів, так і управляючих блоків комутаторів. Проведено порівняння основних характеристик і ступеня надійності комутаційних стійок і тиратронів різного типу. Проведена розробка та впровадження комутаційних стойок на основі шести типів тиратронів: ТГІ1-1000/25, ТГІ1-2500/35, ТГІ1-5000/50, ТГІ1-5к/50 (Росія), ТГІ1-2500/50 (Україна) і СХ 1525 А (Англія).Представлены результаты разработок, эксплуатации и усовершенствований коммутационных стоек. Особое внимание уделено системам контроля и защиты как самих тиратронов, так и управляющих блоков коммутаторов. Проведено сравнение основных характеристик и степени надежности коммутационных стоек и тиратронов различного типа. Проведена разработка и внедрение коммутационных стоек на основе шести типов тиратронов: ТГИ1-1000/25, ТГИ1-2500/35, ТГИ1-5000/50, ТГИ1-5к/50 (Россия), ТГИ1-2500/50 (Украина) и СХ 1525 А (Англия)

Measurements of the spin rotation parameter A in the elastic pion-proton scattering in the D13(1700) resonance region

The spin rotation parameters $A$ and $R$ were measured for the elastic pion-proton scattering by the PNPI-ITEP collaboration in the $D_{13}$(1700) resonance region. The main goal of the experimental program is to resolve the current partial-wave analyses (PWA) uncertainties. Simultaneously with $A$ and $R$ the polarization parameter $P$ was measured with the purpose to improve the experimental database and estimate systematic errors. The constraint which demands a smooth energy dependence of all $\pi^-p$ transverse amplitude zeros in the complex plane together with the new experimental data on $A$ parameter can lead to the conclusion that the Barrelet branch of "zero trajectories" is chosen improperly in PWA of the Carnegie-Mellon-Lawrence-Berkely-Laboratory groups at the range of the pion beam momentum near 1.0 GeV/c. The setup included a longitudinally polarized proton target with superconductive magnet, multiwire spark chambers and carbon polarimeter with thick filter. The experiment was performed at the ITEP proton synchrotron, Moscow