The development of the designs and concepts of the target polarization measurement 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, , Russia. 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, , Russia. N.A. Bazhanov, E.I. Bunyatova Joint Institute for Nuclear Research, Dubna, Moscow district, , Russia. D. Novinsky (PNPI)

 Preface. For nearest 10 years PNPI-ITEP-Dubna collaboration is planning to measure polarization parameters for  N-elastic scattering it follows that we should make the modernization of our experimental setup especially to modernize the proton target polarization measurement.  The experimental setup. Requirements to the polarized target modernization.  PCI-cards and power supply source of superconductive coils.  Algorithm of the polarization measurement.  Conclusions and acknowledgements. Contents D. Novinsky (PNPI) Contents

 Until recent time 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) so we need to continue our investigations.  The polarization experiments at  N-elastic scattering use the proton polarized 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, the measuring circuit of which is excited by a high-frequency fixed-amplitude current, and CAMAC-standard digital measuring equipment, which is connected to computers.  It is needed to make the modernization on the base of PC-cards. Preface D. Novinsky (PNPI) Preface

Experimental Setup 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

Electronic providing of the polarized target  the area under the PMR curve is determined using a Q meter  the measuring circuit of which is excited by a high-frequency fixed-amplitude current  Remote computer PC1 contains a crate controller board and exercises direct control over the measuring system through the CAMAC crate  An RF generator controlled by the sweep DAC produces a saw-tooth sweep  ADC measures the voltage across the Q meter in each scanning cycle  This system also comprises four adjustment DAC : tuning reference voltage phase, to adjust the measuring circuit, to select the PMR frequency (the RF generator frequency) and to control the magnetic field D. Novinsky (PNPI)

Requirements for target modernization  To use the modern digital electronics (PCI-cards) instead of old one on the base of CAMAC.  These PCI cards should request to the next conditions:  PCI standard, two PCI-cards.  One ADC with resolution ≥ 14 bits, digitalization is run by timer, FIFO and transformation time ≤ 8  s; two DACs with resolution ≥ 14 bits,;  8-channel DAC 14-bit resolution;  To avoid an old operation systems (e.g DOS);  Power supply for superconducting coils: compact and to provide more accuracy step along the frequency. D. Novinsky (PNPI)

PCI-card PCI-DAS6036 (MCC)  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)

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)

Electronic providing of the polarized target  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, provides step 15 kHz, no noise on the signal sensitivity level (0.3  V) D. Novinsky (PNPI)

Algorithm of the polarization measurement  The measuring system program is assigned to run with two signals, temperature sensor, sweep DAC and four tuning DACs.  Q-meter, one or two PC, PCI-cards instead of “old” CAMAC.  Sweep DAC handles by HF pulser generating saw-tooth sweep and ADC (input of the phase detector) starts to run by timer. Signal is scanned for  10  s.  Q-meter output voltage is measured by means of ADC at each scanning cycle.  DACs: one to tune the reference voltage phase of the phase detector, one to adjust the measuring circuit, one to select the PMR frequency (the HF generator frequency), and one to control the magnetic field.  Total digitalization time ~ 80  s.  Data taking (e.g. 100 events) ADC  ADC periodically switches to the linear regime, tuning Q-meter contour.  Scanned spectrum is analyzed. The constant component is subtracted from the spectrum obtained thereby, the area under the resultant curve is computed, and this area is converted into the polarization value. D. Novinsky (PNPI)

Conclusions and acknowledgements  Now the measurement system is in the progress in usage of PCI-cards and the new source for superconductive coils power supply works perfectly.  New tests are proposed this year.  International collaboration (“Polarized target”)?  Our thanks to RFBR and  GREAT THANKS to the Organizing Committee of this interesting conference ! ! ! D. Novinsky (PNPI)