Search

DANSS is a solid scintillator antineutrino detector located right below a 3 GWth reactor of the Kalininskaya NPP. One cubic meter of the sensitive volume with fine segmentation makes it possible to achieve an unprecedented counting rate of about 5000 IBD events per day, keeping the level of cosmic background below 2%. New physics with sterile neutrino is searched for by performing spectral measurements at varying distance from the reactor core. Contributions to the applied antineutrino physics include reactor power measurements and fuel analysis. Commissioned in 2016, DANSS accumulated about 4 million antineutrino events by this fall. Advances in the data analysis will be reported, including improvements in the energy calibration and the optimization of the selection cuts. DANSS upgrade plans include new scintillator strips with higher light collection efficiency and better homogeneity. Expected improvement in the energy resolution will significantly increase the experiment sensitivity to the light sterile neutrino.

The Siberian snakes are powerful tools in preserving polarization in high energy accelerators has been demonstrated at the Brookhaven Relativistic Heavy Ion Collider (RHIC). Equipped with two full Siberian snakes in each ring, polarization is preserved during acceleration from injection to 100 GeV. However, the Siberian snakes also introduce a new set of depolarization resonances, i.e. snake resonances as first discoverd by Lee and Tepikian [1]. The intrinsic spin resonances above 100 GeV are about a factor of two stronger than those below 100 GeV which raises the challenge to preserve the polarization up to 250 GeV. In 2009, polarized protons collided for the first time at the RHIC design store energy of 250 GeV. This paper presents the experimental measurements of snake resonances at RHIC. The plan for avoiding these resonanances is also presented.

The RHIC polarized proton complex utilizes polarimeters in each of the Blue and Yellow beams that measure the beam polarization through the p-Carbon elastic scattering process in the Coulomb Nuclear Interference kinematic region. This along with a Polarized Hydrogen Jet Target that utilizes the proton-proton elastic scattering process to first measure the analyzing power of the reaction and using the reverse process to measure the beam polarization. The latter is used to calibrate the p-Carbon polarimeters at the desired beam energy. In Run 9 RHIC ran with beams at center-of-mass energies of 200 and 500 GeV respectively. The higher beam intensities as well as the fact that the 250 GeV beam size is much smaller than that at 100 GeV resulted in significantly higher rates seen by the polarimeters and led to observed instability. In this paper, we will discuss the problems encountered and the tests that were carried out using the AGS as a proxy in an attempt to solve the problems and the path forward we took towards the upcoming polarized proton Run11.