Related papers: Negative Ion Drift and Diffusion in a TPC near 1 B…
We report the first observation of Negative Ion Drift (NID) at surface pressure of $900 \pm 7$ mbar at Laboratori Nazionali del Gran Sasso in a He:CF$_4$:SF$_6$ mixture using an optically read out Time Projection Chamber (TPC) within the…
A Negative Ion Time Projection Chamber was used to measure the field dependence of lateral and longitudinal diffusion for CS$_2$ anions drifting in mixtures of CS$_2$ and Ar at 40 Torr. Ion drift velocities and limits on the capture…
We report new measurements of the drift velocity and longitudinal diffusion coefficients of electrons in pure xenon gas and in xenon-helium gas mixtures at 1-9 bar and electric field strengths of 50-300 V/cm. In pure xenon we find excellent…
Gaseous time projection chambers (TPC) are a very attractive detector technology for particle tracking. Characterization of both drift velocity and diffusion is of great importance to correctly assess their tracking capabilities. NEXT-White…
In the N$\nu$DEx collaboration, a high-pressure gas TPC is being developed to search for the neutrinoless double beta decay. The use of electronegative $\mathrm{^{82}SeF_{6}}$ gas mandates an ion-TPC. The reconstruction of $z$ coordinate is…
High precision measurements were made of reduced mobility, lateral and longitudinal diffusion of CS2- negative ions in 40 Torr CS2 and a 30 - 10 Torr CS2 - CF4 gas mixture. The reduced mobility was found to be 353.0 +/- 0.5 cm^2 Torr / s V…
Low pressure gaseous Negative Ion Time Projection Chambers (NITPCs) have been used previously by the DRIFT experiment to search for a directional Dark Matter (DM) signature. The main challenge with using a Negative Ion Drift (NID) gas…
Understanding the ability to measure and discriminate particle events at the lowest possible energy is an essential requirement in developing new experiments to search for weakly interacting massive particle (WIMP) dark matter. In this…
High precision experiments with muons and pions often require tracking charged particles with $O(100~\mu\mathrm{m})$ single-hit resolution, possibly with particle identification capabilities, down to very low momenta ($p \lesssim…
For the successful design and operation of gas based particle detectors, one needs a good understanding of the drift properties of the deployed gas. This includes the drift velocity of electrons, their diffusion and the gas amplification in…
Measurement of the direction of the elastic nuclear recoil track and ionization charge distribution along it, gives unique possibility for unambiguous detection of the dark matter WIMP particle. Within current radiation detection…
Low-pressure gaseous TPCs are well suited detectors to correlate the directions of nuclear recoils to the galactic Dark Matter (DM) halo. Indeed, in addition to providing a measure of the energy deposition due to the elastic scattering of a…
The Negative Ion Drift (NID) gas SF$_6$ has favourable properties for track reconstruction in directional Dark Matter (DM) searches utilising low pressure gaseous Time Projection Chambers (TPCs). However, the electronegative nature of the…
Three-dimensional track reconstruction is a key issue for directional Dark Matter detection. It requires a precise knowledge of the electron drift velocity. Magboltz simulations are known to give a good evaluation of this parameter.…
We have identified nitromethane (CH$_3$NO$_2$) as an effective electron capture agent for negative ion TPCs (NITPCs). We present drift velocity and longitudinal diffusion measurements for negative ion gas mixtures using nitromethane as the…
A negative ion micro time projection chamber (NI$\mu$TPC) was developed and its performance studied. An NI$\mu$TPC is a novel technology that enables the measurement of absolute $z$ coordinates for self-triggering TPCs. This technology…
The use of negative ions in TPCs has several advantages for high-resolution rare- event detection experiments. The DRIFT experiment, for example, has taken full advantage of this technique over the past decade in a directional search for…
A novel light detection scheme has been tested for use in medium-pressure gas TPCs, in view of rare events searches in low energy particle physics. It has the advantage of minimal interference with the ionization collection system, used for…
The Dark Matter Time Projection Chamber (DMTPC) experiment uses CF_4 gas at low pressure (0.1 atm) to search for the directional signature of Galactic WIMP dark matter. We describe the DMTPC apparatus and summarize recent results from a…
Weakly Interacting Massive Particles (WIMPs) are an attractive candidate for the dark matter thought to make up the bulk of the mass of our universe. We explore here the possibility of using a low pressure negative ion drift chamber to…