J. L. Xu

Limits on spin-dependent WIMP-nucleon cross section obtained from the complete LUX exposure

We present experimental constraints on the spin-dependent WIMP-nucleon elastic cross sections from the total 129.5u2009u2009kgu2009yr exposure acquired by the Large Underground Xenon experiment (LUX), operating at the Sanford Underground Research Facility in Lead, South Dakota (USA). A profile likelihood ratio analysis allows 90%xa0C.L. upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of σ_{n}=1.6×10^{-41}u2009u2009cm^{2} (σ_{p}=5×10^{-40}u2009u2009cm^{2}) at 35u2009u2009GeVu2009c^{-2}, almost a sixfold improvement over the previous LUX spin-dependent results. The spin-dependent WIMP-neutron limit is the most sensitive constraint to date.

Ultralow energy calibration of LUX detector using Xe127 electron capture

Author(s): Akerib, DS; Alsum, S; Araujo, HM; Bai, X; Bailey, AJ; Balajthy, J; Beltrame, P; Bernard, EP; Bernstein, A; Biesiadzinski, TP; Boulton, EM; Bras, P; Byram, D; Cahn, SB; Carmona-Benitez, MC; Chan, C; Currie, A; Cutter, JE; Davison, TJR; Dobi, A; Druszkiewicz, E; Edwards, BN; Fallon, SR; Fan, A; Fiorucci, S; Gaitskell, RJ; Genovesi, J; Ghag, C; Gilchriese, MGD; Hall, CR; Hanhardt, M; Haselschwardt, SJ; Hertel, SA; Hogan, DP; Horn, M; Huang, DQ; Ignarra, CM; Jacobsen, RG; Ji, W; Kamdin, K; Kazkaz, K; Khaitan, D; Knoche, R; Larsen, NA; Lenardo, BG; Lesko, KT; Lindote, A; Lopes, MI; Manalaysay, A; Mannino, RL; Marzioni, MF; McKinsey, DN; Mei, DM; Mock, J; Moongweluwan, M; Morad, JA; Murphy, ASJ; Nehrkorn, C; Nelson, HN; Neves, F; OSullivan, K; Oliver-Mallory, KC; Palladino, KJ; Pease, EK; Rhyne, C; Shaw, S; Shutt, TA; Silva, C; Solmaz, M; Solovov, VN; Sorensen, P; Sumner, TJ; Szydagis, M; Taylor, DJ; Taylor, WC; Tennyson, BP; Terman, PA; Tiedt, DR; To, WH; Tripathi, M; Tvrznikova, L; Uvarov, S; Velan, V; Verbus, JR; Webb, RC | Abstract:

Position reconstruction in LUX

Author(s): Akerib, DS; Alsum, S; Arauandjo, HM; Bai, X; Bailey, AJ; Balajthy, J; Beltrame, P; Bernard, EP; Bernstein, A; Biesiadzinski, TP; Boulton, EM; Braands, P; Byram, D; Cahn, SB; Carmona-Benitez, MC; Chan, C; Currie, A; Cutter, JE; Davison, TJR; Dobi, A; Druszkiewicz, E; Edwards, BN; Fallon, SR; Fan, A; Fiorucci, S; Gaitskell, RJ; Genovesi, J; Ghag, C; Gilchriese, MGD; Hall, CR; Hanhardt, M; Haselschwardt, SJ; Hertel, SA; Hogan, DP; Horn, M; Huang, DQ; Ignarra, CM; Jacobsen, RG; Ji, W; Kamdin, K; Kazkaz, K; Khaitan, D; Knoche, R; Larsen, NA; Lenardo, BG; Lesko, KT; Lindote, A; Lopes, MI; Manalaysay, A; Mannino, RL; Marzioni, MF; McKinsey, DN; Mei, DM; Mock, J; Moongweluwan, M; Morad, JA; Murphy, ASJ; Nehrkorn, C; Nelson, HN; Neves, F; OSullivan, K; Oliver-Mallory, KC; Palladino, KJ; Pease, EK; Rhyne, C; Shaw, S; Shutt, TA; Silva, C; Solmaz, M; Solovov, VN; Sorensen, P; Sumner, TJ; Szydagis, M; Taylor, DJ; Taylor, WC; Tennyson, BP; Terman, PA; Tiedt, DR; To, WH; Tripathi, M; Tvrznikova, L; Uvarov, S; Velan, V; Verbus, JR; Webb, RC | Abstract:

Kr83m calibration of the 2013 LUX dark matter search

Author(s): Akerib, DS; Alsum, S; Araujo, HM; Bai, X; Bailey, AJ; Balajthy, J; Beltrame, P; Bernard, EP; Bernstein, A; Biesiadzinski, TP; Boulton, EM; Bras, P; Byram, D; Cahn, SB; Carmona-Benitez, MC; Chan, C; Currie, A; Cutter, JE; Davison, TJR; Dobi, A; Druszkiewicz, E; Edwards, BN; Fallon, SR; Fan, A; Fiorucci, S; Gaitskell, RJ; Genovesi, J; Ghag, C; Gilchriese, MGD; Hall, CR; Hanhardt, M; Haselschwardt, SJ; Hertel, SA; Hogan, DP; Horn, M; Huang, DQ; Ignarra, CM; Jacobsen, RG; Ji, W; Kamdin, K; Kazkaz, K; Khaitan, D; Knoche, R; Larsen, NA; Lenardo, BG; Lesko, KT; Lindote, A; Lopes, MI; Manalaysay, A; Mannino, RL; Marzioni, MF; McKinsey, DN; Mei, DM; Mock, J; Moongweluwan, M; Morad, JA; Murphy, ASJ; Nehrkorn, C; Nelson, HN; Neves, F; OSullivan, K; Oliver-Mallory, KC; Palladino, KJ; Pease, EK; Rhyne, C; Shaw, S; Shutt, TA; Silva, C; Solmaz, M; Solovov, VN; Sorensen, P; Sumner, TJ; Szydagis, M; Taylor, DJ; Taylor, WC; Tennyson, BP; Terman, PA; Tiedt, DR; To, WH; Tripathi, M; Tvrznikova, L; Uvarov, S; Velan, V; Verbus, JR; Webb, RC | Abstract:

3D modeling of electric fields in the LUX detector

Author(s): Akerib, DS; Alsum, S; Araujo, HM; Bai, X; Bailey, AJ; Balajthy, J; Beltrame, P; Bernard, EP; Bernstein, A; Biesiadzinski, TP; Boulton, EM; Bras, P; Byram, D; Cahn, SB; Carmona-Benitez, MC; Chan, C; Currie, A; Cutter, JE; Davison, TJR; Dobi, A; Druszkiewicz, E; Edwards, BN; Fallon, SR; Fan, A; Fiorucci, S; Gaitskell, RJ; Genovesi, J; Ghag, C; Gilchriese, MGD; Hall, CR; Hanhardt, M; Haselschwardt, SJ; Hertel, SA; Hogan, DP; Horn, M; Huang, DQ; Ignarra, CM; Jacobsen, RG; Ji, W; Kamdin, K; Kazkaz, K; Khaitan, D; Knoche, R; Larsen, NA; Lenardo, BG; Lesko, KT; Lindote, A; Lopes, MI; Manalaysay, A; Mannino, RL; Marzioni, MF; McKinsey, DN; Mei, DM; Mock, J; Moongweluwan, M; Morad, JA; Murphy, ASJ; Nehrkorn, C; Nelson, HN; Neves, F; OSullivan, K; Oliver-Mallory, KC; Palladino, KJ; Pease, EK; Rhyne, C; Shaw, S; Shutt, TA; Silva, C; Solmaz, M; Solovov, VN; Sorensen, P; Sumner, TJ; Szydagis, M; Taylor, DJ; Taylor, WC; Tennyson, BP; Terman, PA; Tiedt, DR; To, WH; Tripathi, M; Tvrznikova, L; Uvarov, S; Velan, V; Verbus, JR; Webb, RC | Abstract:

Calibration algorithms of RPC detectors at Daya Bay Neutrino Experiment

During the commissioning of RPC detector systems at the Daya Bay Reactor Neutrino Experiment, calibration algorithms were developed and tuned, in order to evaluate and optimize the performance of the RPC detectors. Based on a description of the hardware structure of the RPC detector systems, this paper introduces the algorithms used for detector calibration, including trigger rate, efficiency, noise rate, purity and muon flux.

Developments of oil-free Bakelite resistive plate chambers for particle physics experiments

In this paper, we sumarized a Bakelite Resistive Plate Chamber (RPC) with non-oil surface treatment. This type of RPC has been installed and run smoothly in BESIII Muon identification system and Daya Bay cosmic Muon veto system. Based on its good performances, it has been futher studied as the sensitive detector of a digital hadron calorimeter for measuring the energies of particles in a hadron jet and as a thermal neutron detector. In addition, since the bulk resistivity of Bakelite plates can be controlled, futher developments with low bulk resistivity are being undertaken to guarantee high rate capability in experiments.

STUDY OF NEUTRON RADIATION FIELD AT THE FIRST RADIOACTIVE ION BEAM LINE IN LANZHOU

The first Radioactive Ion Beam Line in Lanzhou was a projectile fragment separator located in the HIRFL. The process of production and separation of radioactive ion beams can induce a strong and complex radiation field. The neutron dose equivalent rates were measured in four positions with a 70 MeV/u 40Ar18+ beam. The results were compared with that simulated by the FLUKA code. New shielding walls were installed to reduce the neutron background for spectroscopy measurement in the experimental terminal. In addition, the induced radioactivity of accelerator components and corresponding residual dose rates were analyzed for the radiation safety of accelerator workers. The airborne radioactivity as well as occupational exposure due to immersion in and inhalation of activated air were also estimated. This work aims to provide a valuable experience for the radiation study in the future fragment separator HFRS at HIAF.

Study of neutron dose equivalent at the HIRFL deep tumor therapy terminal

The secondary neutron fields at the deep tumor therapy terminal at HIRFL (Heavy Ion Research Facility in Lanzhou) were investigated. The distributions of neutron ambient dose equivalent were measured with a FHT762 Wendi-II neutron ambient dose equivalent meter as the 12C ions with energies of 165, 207, 270, and 350 MeV/u bombarded on thick tissue-like targets. The thickness of targets used in experiments is larger than the range of the carbon ions. The neutron spectra and dose equivalent is simulated by using FLUKA code, and the results agree well with the experimental data. The experiment results showed that the neutron dose produced by fragmentation reactions in tissue can be neglected in carbon-ion therapy, even considering their enhanced biological effectiveness. These results are also valuable for radiation protection, especially in the shielding design of high energy heavy ion medical machines.

Evaluation of neutron radiation field in carbon ion therapy

Carbon ions have significant advantages in tumor therapy because of their physical and biological properties. In view of the radiation protection, the safety of patients is the most important issue in therapy processes.Therefore, the effects of the secondary particles produced by the carbon ions in the tumor therapy should be carefully considered, especially for the neutrons. In the present work, the neutron radiation field induced by carbon ions was evaluated by using the FLUKA code. The simulated results of neutron energy spectra and neutron dose was found to be in good agreement with the experiment data. In addition, energy deposition of carbon ions and neutrons in tissue-like media was studied, it is found that the secondary neutron energy deposition is not expected to exceed 1% of the carbon ion energy deposition in a typical treatment.Carbon ions have significant advantages in tumor therapy because of their physical and biological properties. In view of the radiation protection, the safety of patients is the most important issue in therapy processes. Therefore, the effects of the secondary particles produced by the carbon ions in the tumor therapy should be carefully considered, especially for the neutrons. In the present work, the neutron radiation field induced by carbon ions was evaluated by using the FLUKA code. The simulated results of neutron energy spectra and neutron dose was found to be in good agreement with the experiment data. In addition, energy deposition of carbon ions and neutrons in tissue-like media was studied, it is found that the secondary neutron energy deposition is not expected to exceed 1% of the carbon ion energy deposition in a typical treatment.