1. PNPI polarized target for pion-nucleon scattering measurements at intermediate energies A.V Aldushchenkov, A.G. Dernyatin, A.I. Kovalev, D.V. Novinsky, I. Okunev, V.A. Shchedrov, V.V. Sumachev, V.Yu. Trautman. Petersburg Nuclear Physics Institute, Gatchina, Leningrad district, 188350, Russia. E-mail : dimanov@pnpi.spb.ru I.G. Alekseev, P.E. Budkovsky, V.P. Kanavets, L.I. Koroleva, B.V. Morozov, V.M. Nesterov, V.V. Ryltsov, D.N. Svirida, A.D. Sulimov. Institute for Theoretical and Experimental Physics, Moscow, 117218, Russia. N.A. Bazhanov, E.I. Bunyatova Joint Institute for Nuclear Research, Dubna, Moscow district, 141980, Russia. D. Novinsky (PNPI)

2.  The polarization parameters (P, R, A) measurement results above pion momentum above 1000 MeV/c made it possible to resolve part of discrete ambiguities in existing partial-wave analyses (PWA’s)  The polarization experiments at  N-elastic scattering use the proton polarized target.  The experiment uses a polarized proton target in which free protons have vertical polarization or polarization in the elastic scattering plane.  Uncertainty (abs.) is ±~2% at 70% of polarization magnitude.  The area under the PMR curve is determined using a Q meter. Preface D. Novinsky (PNPI)

3. The physics goals D. Novinsky (PNPI)

4. Experimental Setup, ITEP (Moscow) D. Novinsky (PNPI) MAIN ELEMENTS:  Vertically polarized proton target PT  4 sets of wire chambers for tracking  Trigger scintillation counters TARGET:  Cylinder  30mm, h=30mm, propanediole C 3 H 8 O 2, free proton density  10 %  Magnetic field 2.5 T  3 He evaporation type cryostat at 0.5 K  Dynamic nuclear orientation  Polarization (70-80) %, measurement accuracy ±2 %  Sign reverse once per day Beam Arm Proton Arm Pion Arm I Pion Arm II Pion Beam

5. Cryostat in the vertical sectional view D. Novinsky (PNPI) 1 – helium-3 pump-out 2 – neck 3 – helium-4 pump-out 4,11 – nitrogen screens 5,21 – helium inputs 6– nitrogen tank 7– magnet 8 – window 9 – magnet frame 10 – housing 12 – indium compaction 13 – rotating tee-joint 14 – helium-4 output through current-input 15 – connection to current source 16 – current-input compaction and helium-4 output 17 – current-input 18 – helium tank (at 4.2 K) 19 – refrigerator 20 – appendix with target (C 3 H 8 O 2 ) matter

6. Target: topview plane D. Novinsky (PNPI) 1 – target window, 2 – nitrogen screen, 3 – magnet area, 4 – container with the target (C 3 H 8 O 2 ) matter inside superconductive Helmholz coils

7. Polarization measurements D. Novinsky (PNPI)  polarization pump by the dynamic nuclear orientation method up to absolute value 70– 80%  method of proton magnetic resonance (PMR),  measurements are based on the calculations of square under the PMR curve: the system containing Q-meter with sequential contour and signal digitalization  Calibration is based on the equilibrium state at temperature 0.8 – 1.4 K

8. Polarization measurements D. Novinsky (PNPI)  Signal and background  Background: to take away signal from center by means of the magnetic field change

9. Polarization measurements D. Novinsky (PNPI)  Calibration: the equilibrium state

10. Electronic providing of the polarized target  Modernization of the target measurements  Two PCI-cards are inserted into the PC-board (Remote computer PC1 ).  Usage of PCI-card DAS6036 and the PCI-card PCI-1723 ADC and DAC with grade ≥ 14 bit, transformation is run by timer FIFO Transformation time ≤ 8  s  Usage of the new current source “Lambda-Genesys” for power supply of superconductive coils D. Novinsky (PNPI)

11. Current situation D. Novinsky (PNPI)  PCI-cards and programs are tested at PNPI  Current source is tested at PNPI and ITEP (Moscow)  Target location: ITEP  To continue spin rotation parameters mearurements, e.g. J-PARC  at PNPI accelerator  Cryostat at PNPI Netron Physics Department

12.  More than 20 years experiments Conclusions Acknowledgements  GREAT THANKS to the Organizing Committee ! ! ! D. Novinsky (PNPI)  Successful target work > 20 years  Modernization and new tests are required  New physics tasks  In memory of A.I. Kovalev (1936-2011)

13. PCI-card PCI-DAS6036  Low-cost, 16-channel, 200 kS/s analog I/O boards with two 16-bit analog outputs, eight digital I/O, and two counter/timers  16 channels of 16-bit A/D resolution  200 kS/s maximum sample rate  2 channels of 16-bit D/A at 10 kHz  8 bits DIO  2 16-bit counters D. Novinsky (PNPI)

14. PCI-card PCI-1723 (Advantech)  16-bit, 8-channel Non-isolated Analog Output CardMain Features  Auto calibration function  A 16-bit DAC is equipped for each analog output channel  Synchronized output function  Output values retained after system hot reset  2-port (16-channel) user-defined digital input/output  Board ID D. Novinsky (PNPI)