K. Yasuda — Page 2 | Searcharxiv

arXiv2006

The performance of thin NaI(Tl) scintillator plate for dark matter search

A thin (0.05cm) and wide area (5cmX5cm) NaI(Tl) scintillator was developed. The performance of the thin NaI(Tl) plate, energy resolution, single photoelectron energy and position sensitivity were tested. An excellent energy resolution of 20% (FWHM) at 60keV was obtained. The single photoelectron energy was calculated to be approximately 0.42 0.02keV. Position information in the 5cmx5cm area of the detector was also obtained by analyzing the ratio of the number of photons collected at opposite ends of the detector. The position resolution was obtained to be 1cm (FWHM) in the 5cmx5cm area.

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arXiv2002

Analyzing power of the ${\vec p}p \to ppπ^0$ reaction at beam energy of 390 MeV

The analyzing power of ${\vec p}p\to ppπ^0$ reaction has been measured at the beam energy of 390 MeV. The missing mass technique of final protons has been applied to identify the $π^0$ production event. The dependences of the analyzing power on the pion emission-angle and the relative momentum of the protons have beenobtained. The angular dependence could be decomposed by the Legendre polynomial and the relative contribution of the $P_{21}$ to $P_{11}$ function is less than 20%. The P-state amplitude is found to be the dominant component of the $π$ production near the threshold. The momentum dependence of the analyzing power has been studied to obtain the information about the pion production mechanism. It has been deduced that the pion production due to the long range interaction plays an important role in the momentum dependence of the P-state amplitude.

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