A. Kaboth

First dark matter search results from a surface run of the 10-L DMTPC directional dark matter detector

Abstract The Dark Matter Time Projection Chamber (DMTPC) is a low pressure (75 Torr CF4) 10 liter detector capable of measuring the vector direction of nuclear recoils with the goal of directional dark matter detection. In this Letter we present the first dark matter limit from DMTPC from a surface run at MIT. In an analysis window of 80–200 keV recoil energy, based on a 35.7 g-day exposure, we set a 90% C.L. upper limit on the spin-dependent WIMP-proton cross section of 2.0 × 10 − 33 cm 2 for 115 GeV/c2 dark matter particle mass.

Focal-plane detector system for the KATRIN experiment

Abstract The focal-plane detector system for the KArlsruhe TRItium Neutrino (KATRIN) experiment consists of a multi-pixel silicon p-i-n-diode array, custom readout electronics, two superconducting solenoid magnets, an ultra high-vacuum system, a high-vacuum system, calibration and monitoring devices, a scintillating veto, and a custom data-acquisition system. It is designed to detect the low-energy electrons selected by the KATRIN main spectrometer. We describe the system and summarize its performance after its final installation.

A background-free direction-sensitive neutron detector

The detection and measurements of properties of neutrons are of great importance in many fields of research, including neutron scattering and radiography, measurements of solar and cosmic ray neutron flux, measurements of neutron interaction cross sections, monitoring of neutrons at nuclear facilities, oil exploration, and searches for fissile weapons of mass destruction. Many neutron detectors are plagued by large backgrounds from x-rays and gamma rays, and most current neutron detectors lack single-event energy sensitivity or any information on neutron directionality. Even the best detectors are limited by cosmic ray neutron backgrounds. All applications would benefit from improved neutron detection sensitivity and improved measurements of neutron properties. Here we show data from a new type of detector that can be used to determine neutron flux, energy distribution, and direction of neutron motion. The detector is free of backgrounds from x-rays, gamma rays, beta particles, and relativistic singly charged particles. It is relatively insensitive to cosmic ray neutrons because of their distinctive angular and energy distributions. It is sensitive to thermal neutrons, fission spectrum neutrons, and high energy neutrons, with detection features distinctive for each energy range. It is capable of determining the location of a source of fission neutrons based on characteristics of elastic scattering of neutrons by helium nuclei. A portable detector could identify one gram of reactor grade plutonium, one meter away, with less than one minute of observation time.

Sensitivity of Neutrino Mass Experiments to the Cosmic Neutrino Background

The KATRIN neutrino experiment is a next-generation tritium beta decay experiment aimed at measuring the mass of the electron neutrino to better than 200 meV at 90% C.L. Because of its intense tritium source, KATRIN can also serve as a possible target for the process of neutrino capture, {nu}{sub e}+{sup 3}H{yields}{sup 3}He{sup +}+e{sup -}. The latter process, possessing no energy threshold, is sensitive to the cosmic neutrino background (C{nu}B). In this paper, we explore the potential sensitivity of the KATRIN experiment to the relic neutrino density. The KATRIN experiment is sensitive to a C{nu}B overdensity ratio of 2.0x10{sup 9} over standard concordance model predictions (at 90% C.L.), addressing the validity of certain speculative cosmological models.

Testing charged current quasi-elastic and multinucleon interaction models in the NEUT neutrino interaction generator with published datasets from the MiniBooNE and MINERνA experiments

The MiniBooNE large axial mass anomaly has prompted a great deal of theoretical work on sophisticated Charged Current Quasi-Elastic (CCQE) neutrino interaction models in recent years. As the dominant interaction mode at T2K energies, and the signal process in oscillation analyses, it is important for the T2K experiment to include realistic CCQE cross section uncertainties in T2K analyses. To this end, T2Ks Neutrino Interaction Working Group has implemented a number of recent models in NEUT, T2Ks primary neutrino interaction event generator. In this paper, we give an overview of the models implemented, and present fits to published muon neutrino and muon antineutrino CCQE cross section measurements from the MiniBooNE and MINERvA experiments. The results of the fits are used to select a default cross section model for future T2K analyses, and to constrain the cross section uncertainties of the model. We find a model consisting of a modified relativistic Fermi gas model and multinucleon interactions most consistently describes the available data.

Accelerated event-by-event neutrino oscillation reweighting with matter effects on a GPU

Oscillation probability calculations are becoming increasingly CPU intensive in modern neutrino oscillation analyses. The independency of reweighting individual events in a Monte Carlo sample lends itself to parallel implementation on a graphics processing unit. The library Prob3++ was ported to the GPU using the CUDA C API, allowing for large scale parallelized calculations of neutrino oscillation probabilities through matter of constant density, decreasing the execution time by 2 orders of magnitude when compared to performance on a single CPU.

Results from DMTPC 10-liter detector

The known direction of motion of dark matter particles relative to the Earth may be a key for their unambiguous identification even in the presence of backgrounds. A direction-sensitive detector prototype using a low-density CF4 gas with a 10 liter fiducial volume is operated for several weeks in a basement laboratory. We present initial results that confirm good detector performance and set preliminary limits on spin-dependent dark matter interactions.

DMTPC: A dark matter detector with directional sensitivity

By correlating nuclear recoil directions with the Earth’s direction of motion through the Galaxy, a directional dark matter detector can unambiguously detect Weakly Interacting Massive Particles (WIMPs), even in the presence of backgrounds. Here, we describe the Dark Matter Time‐Projection Chamber (DMTPC) detector, a TPC filled with CF4 gas at low pressure (0.1 atm). Using this detector, we have measured the vector direction (head‐tail) of nuclear recoils down to energies of 100 keV with an angular resolution of ≤15°. To study our detector backgrounds, we have operated in a basement laboratory on the MIT campus for several months. We are currently building a new, high‐radiopurity detector for deployment underground at the Waste Isolation Pilot Plant facility in New Mexico.

The DMTPC detector

Directional Dark Matter detectors have the potential of yielding an unambiguous observation of WIMPs even in presence of insidious background. In addition, by measuring the direction of the Dark Matter particles such detectors can discriminate between the various models that describe Dark Matter in our galaxy. The DMTPC detector is a novel directional DM detector consisting of a low-pressure CF4 time projection chamber with optical readout. Recent measurements proved that this technology is able to reconstruct the energy, direction, and sense of the lowenergy nuclear recoils produced by neutrons from a 252Cf source, as well as efficiently reject electromagnetic backgrounds. A 10-liter DMTPC detector is ready for underground operation. A 1 m3 detector, now in the design phase, will soon allow us to improve the existing limits of SD-interactions of WIMPs on protons by over one order of magnitude.

Dark Matter Time Projection Chamber: Recent R&D Results

The Dark Matter Time Projection Chamber collaboration recently reported a dark matter limit obtained with a 10 liter time projection chamber lled with CF 4 gas. The 10 liter detector was capable of 2D tracking (perpendicular to the drift direction) and 2D ducialization, and only used information from two CCD cameras when identifying tracks and rejecting backgrounds. Since that time, the col- laboration has explored the potential benets of photomultiplier tube and electronic charge readout to achieve 3D tracking, and particle iden- tication for background rejection. The latest results of this eort is described here.