Fri·Jan 13, 2023Friday·January 13, 2023

1. 01*

   Two-Photon EXchange -- TPEX

   R. Alarcon · R. Beck · J. C. Bernauer · M. Broering · E. Cline · B. Dongwi · I. Fernando · M. Finger · M. Finger Jr. · I. Friščić · T. Gautam · D. K. Hasell and 25 other authors

   We propose a new measurement of the ratio of positron-proton to electron-proton, elastic scattering at DESY to determine the contributions beyond single-photon exchange, which are essential to the QED description of the most fundamental process in hadronic physics. A 20~cm long liquid hydrogen target together with the extracted beam from the DESY synchrotron would yield an average luminosity of $2.12\times 10^{35}$~cm${}^{-2}\cdot$s${}^{-1}\cdot$sr${}^{-1}$ ($\sim 200$ times the luminosity achieved by OLYMPUS). A commissioning run at 2 GeV followed by measurements at 3 GeV would provide new data up to $Q^2=4.6$~(GeV/$c$)${}^2$ (twice the range of current measurements). Lead tungstate calorimeters would be used to detect the scattered leptons at polar angles of $30^{\circ }$, $50^{\circ }$, $70^{\circ }$, $90^{\circ }$, and $110^{\circ }$. The measurements could be scheduled to not interfere with the operation of PETRA. We present rate estimates and simulations for the planned measurements including background considerations. Initial measurements at the DESY test beam facility using prototype lead tungstate calorimeters in 2019, 2021, and 2022 were made to check the Monte Carlo simulations and the performance of the calorimeters. These tests also investigated different readout schemes (triggered and streaming). Various upgrades are possible to shorten the running time and to make higher beam energies and thus greater $Q^2$ ranges accessible.

   nucl-exphysics.ins-det4 citations
2. 02*

   Performance of an ultra-pure NaI(Tl) detector produced by an indigenously-developed purification method and crystal growth for the COSINE-200 experiment

   Hyun Seok Lee🇰🇷 · Byung Ju Park🇰🇷 · Jae Jin Choi🇰🇷 · Olga Gileva🇰🇷 · Chang Hyon Ha🇰🇷 · Alain Iltis🇫🇷 · Eun Ju Jeon🇰🇷 · Dae Yeon Kim🇰🇷 · Kyung Won Kim🇰🇷 · Sung Hyun Kim🇰🇷 · Sun Kee Kim🇰🇷 · Yeong Duk Kim and 8 other authors

   The COSINE-100 experiment has been operating with 106 kg of low-background NaI(Tl) detectors to test the results from the DAMA/LIBRA experiment, which claims to have observed dark matter. However, since the background of the NaI(Tl) crystals used in the COSINE-100 experiment is 2-3 times higher than that in the DAMA detectors, no conclusion regarding the claimed observation from the DAMA/LIBRA experiment could be reached. Therefore, we plan to upgrade the current COSINE-100 experiment to the next phase, COSINE-200, by using ultra-low background NaI(Tl) detectors. The basic principle was already proved with the commercially available Astro-grade NaI powder from Sigma-Aldrich company. However, we have developed a mass production process of ultra-pure NaI powder at the Center for Underground Physics (CUP) of the Institute for Basic Science (IBS), Korea, using the direct purification of the raw NaI powder. We plan to produce more than 1,000 kg of ultra-pure powder for the COSINE200 experiment. With our crystal grower installed at CUP, we have successfully grown a low-background crystal using our purification technique for the NaI powder. We have assembled a low-background NaI(Tl) detector. In this article, we report the performance of this ultra-pure NaI(Tl) crystal detector produced at IBS, Korea.

   ↳ physics.ins-detastro-ph.IMhep-exnucl-exFront.in Phys.(2023)·11 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.