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Measuring the Low Energy Nuclear Quenching Factor in Liquid Argon for a Coherent Neutrino Scatter Detector
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Nuclear Physics B (Proc. Suppl.) 229–232 (2012) 512 www.elsevier.com/locate/npbps
Measuring the Low Energy Nuclear Quenching Factor in Liquid Argon for a Coherent Neutrino Scatter Detector M. Foxea,b,d , A. Bernsteinb , C. Hagmannb , T. Joshic,b , I. Jovanovica , K. Kazkazb , S. Sangiorgiob a Department
of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, PA 16802 b Lawrence Livermore National Laboratory, Livermore CA 94550 c Department of Nuclear Engineering, University of California, Berkeley, CA 94720 d Corresponding Author, [email protected]
Abstract Coherent neutrino-nucleus scattering (CNS) is an as-yet undetected, flavor-independent neutrino interaction predicted by the Standard Model [1]. One of the primary reasons the CNS interaction has yet to be observed is the very low energy depositions (less than 1 keV for MeV-energy neutrinos) [2]. An additional challenge in detecting CNS is nuclear quenching, which is a phenomenon encountered in many detection materials in which nuclear recoils produce less observable energy per unit energy deposited than electronic recoils. The ratio observed signal for nuclear recoils to electronic recoils or nuclear ionization quench factor, is presently unknown in argon at typical CNS energies [3]. Here we present plans for using the Gamma or Neutron Argon Recoils Resulting in Liquid Ionization (G/NARRLI) detector to measure the nuclear ionization quench factor at ∼8 keV. Keywords: coherent neutrino-nucleus scatter, antineutrino, liquid argon, nuclear quench factor, reactor, ionization yield
1. Nuclear Ionization Quench Factor We have built the Gamma or Neutron Argon Recoils Resulting in Liquid Ionization (G/NARRLI) detector [4], for the purpose of measuring the nuclear ionization quench factor, Equation 1, in liquid argon [5]. qion (E) = N nucl (E)/N elec (E) ion ion
(1)
We plan to measure the nuclear ionization quench factor with a 1.93 MeV proton beam on a lithium target, producing neutrons from 0-135 keV in energy [6]. These neutrons will then scatter off the argon, primarily in the 80 keV resonance, producing the expected signal shown in Figure 1. Taking the ratio of observed to expected end-point in measured ionization energy, we plan to obtain the quench factor at ∼8 keV. [1] D. Freedman, Phys. Rev. D 9 (5) (1974) 1389–1392. [2] A. Drukier, L. Stodolsky, Phys. Rev. D 30 (11) (1984) 2295– 2309.
0920-5632/$ – see front matter, Published by Elsevier B.V. doi:10.1016/j.nuclphysbps.2012.09.149
Figure 1: Predicted recoil (red) and quenched signal (blue) spectra, assuming a nuclear ionization quench factor of 0.2
[3] C. Hagmann, A. Bernstein, IEEE Trans. on Nucl. Sci. 51 (5) (2004) 2151–2155. [4] S. Sangiorgio et. al, IEEE Nucl. Sci. Symposium Conference Record (Knoxville, TN, Nov. 2010) N05–2. [5] M. Foxe et. al, IEEE Nucl. Sci. Symposium Conference Record (Knoxville, TN, Nov. 2010) N05–3. [6] C. Lee, X. Zhou, Nucl. Instrum. Methods B 152 (1) (1999) 1–11.
Nuclear Physics B (Proc. Suppl.) 229–232 (2012) 512 www.elsevier.com/locate/npbps
Measuring the Low Energy Nuclear Quenching Factor in Liquid Argon for a Coherent Neutrino Scatter Detector M. Foxea,b,d , A. Bernsteinb , C. Hagmannb , T. Joshic,b , I. Jovanovica , K. Kazkazb , S. Sangiorgiob a Department
of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, PA 16802 b Lawrence Livermore National Laboratory, Livermore CA 94550 c Department of Nuclear Engineering, University of California, Berkeley, CA 94720 d Corresponding Author, [email protected]
Abstract Coherent neutrino-nucleus scattering (CNS) is an as-yet undetected, flavor-independent neutrino interaction predicted by the Standard Model [1]. One of the primary reasons the CNS interaction has yet to be observed is the very low energy depositions (less than 1 keV for MeV-energy neutrinos) [2]. An additional challenge in detecting CNS is nuclear quenching, which is a phenomenon encountered in many detection materials in which nuclear recoils produce less observable energy per unit energy deposited than electronic recoils. The ratio observed signal for nuclear recoils to electronic recoils or nuclear ionization quench factor, is presently unknown in argon at typical CNS energies [3]. Here we present plans for using the Gamma or Neutron Argon Recoils Resulting in Liquid Ionization (G/NARRLI) detector to measure the nuclear ionization quench factor at ∼8 keV. Keywords: coherent neutrino-nucleus scatter, antineutrino, liquid argon, nuclear quench factor, reactor, ionization yield
1. Nuclear Ionization Quench Factor We have built the Gamma or Neutron Argon Recoils Resulting in Liquid Ionization (G/NARRLI) detector [4], for the purpose of measuring the nuclear ionization quench factor, Equation 1, in liquid argon [5]. qion (E) = N nucl (E)/N elec (E) ion ion
(1)
We plan to measure the nuclear ionization quench factor with a 1.93 MeV proton beam on a lithium target, producing neutrons from 0-135 keV in energy [6]. These neutrons will then scatter off the argon, primarily in the 80 keV resonance, producing the expected signal shown in Figure 1. Taking the ratio of observed to expected end-point in measured ionization energy, we plan to obtain the quench factor at ∼8 keV. [1] D. Freedman, Phys. Rev. D 9 (5) (1974) 1389–1392. [2] A. Drukier, L. Stodolsky, Phys. Rev. D 30 (11) (1984) 2295– 2309.
0920-5632/$ – see front matter, Published by Elsevier B.V. doi:10.1016/j.nuclphysbps.2012.09.149
Figure 1: Predicted recoil (red) and quenched signal (blue) spectra, assuming a nuclear ionization quench factor of 0.2
[3] C. Hagmann, A. Bernstein, IEEE Trans. on Nucl. Sci. 51 (5) (2004) 2151–2155. [4] S. Sangiorgio et. al, IEEE Nucl. Sci. Symposium Conference Record (Knoxville, TN, Nov. 2010) N05–2. [5] M. Foxe et. al, IEEE Nucl. Sci. Symposium Conference Record (Knoxville, TN, Nov. 2010) N05–3. [6] C. Lee, X. Zhou, Nucl. Instrum. Methods B 152 (1) (1999) 1–11.