Bragg-like curve for dark matter searches: Binary gases

Hitachi, A.

doi:10.1016/j.radphyschem.2008.05.044

Cited by 28 publications

(28 citation statements)

References 17 publications

(21 reference statements)

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“…The final NIPs value for the event is the sum Table 1: NIPs yield as a function of energy for fluorine recoils, from Ref. [35].…”

Section: Discussionmentioning

confidence: 99%

“…Elastic and inelastic interactions with nuclei within the fiducial volume had their recoil types, initial energies, and initial interaction locations recorded. The initial recoil energies were converted to NIPs using quenching factors calculated by Hitachi [35] and validated experimentally in [28]. A similar simulation of the DRIFT-IIa detector showed 100 ± 2% (statistical) ±5% (systematic) efficiency after the Stage 1 cuts and background subtraction for large NIP events [23].…”

Section: Nuclear Recoil Efficiencymentioning

confidence: 99%

“…The top axis gives nuclear recoil energy as inferred from Ref. [35]. Fluorine recoil energy (keV) Figure 4: An efficiency map for recoil detection including all analysis cuts.…”

Section: Wimp Recoil Simulation and Limitsmentioning

confidence: 99%

“…The top axis gives nuclear recoil energy as inferred from Ref. [35]. The overall event rate is expected to be higher at large z due to the placement of the 252 Cf source near the central cathode.…”

Section: Wimp Recoil Simulation and Limitsmentioning

confidence: 99%

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First background-free limit from a directional dark matter experiment: Results from a fully fiducialised DRIFT detector

Battat

Brack

Daw

et al. 2015

Physics of the Dark Universe

105

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The addition of O 2 to gas mixtures in time projection chambers containing CS 2 has recently been shown to produce multiple negative ions that travel at slightly different velocities. This allows a measurement of the absolute position of ionising events in the z (drift) direction. In this work, we apply the z-fiducialisation technique to a directional dark matter search. We present results from a 46.3 live-day source-free exposure of the DRIFT-IId detector run in this new mode. With full-volume fiducialisation, we have achieved the first background-free operation of a directional detector. The resulting exclusion curve for spindependent WIMP-proton interactions reaches 1.1 pb at 100 GeV/c 2 , a factor of 2 better than our previous work. We describe the automated analysis used here, and argue that detector upgrades, implemented after the acquisition of these data, will bring an additional factor of 3 improvement in the near future.arXiv:1410.7821v3 [hep-ex] 23 Jul 2015 DRIFT-IId detector and science runsThe DRIFT experiment is sited at a depth of 1.1 km in the STFC Boulby Underground Science Facility [29], which provides 2805 m.w.e. shielding against cosmic rays. The TPC is housed inside a stainless steel cubic vacuum vessel, surrounded on all sides with 44 g cm −2 of polypropylene pellets to shield against neutrons from the cavern walls. The vessel was filled with a mixture of 30:10:1 Torr CS 2 :CF 4 :O 2 gas, and sealed for the duration of each run. This departure from the normal mode of operation, in which gas is flowed at a constant rate of one complete vacuum vessel change (590 g) /d, was necessary due to safety concerns over sources of ignition in the constant flow system. These concerns have since been addressed with modifications to the gas system.The DRIFT-IId NITPC consists of a thin-film (0.9 µm aluminised Mylar), texturised central cathode [25] at a potential of -31.9 kV faced on either side by two 1 m 2 multi-wire proportional chambers (hereafter, the 'left' and 'right' MWPCs) at a distance of 50 cm. In this way, two 50-cm-long drift regions are defined. A field cage of 31 stainless steel rings on either side steps down the voltage smoothly between the central cathode and the MWPCs to ensure a uniform electric field of 580 V cm −1 throughout the drift regions. The MWPCs are made up of a central grounded anode plane of 20 µm diameter stainless steel wires with 2 mm pitch, sandwiched between two perpendicular grid planes of 100 µm wires at -2884 V, again with 2 mm pitch and separated by 1 cm from the anode plane. A full description of the detector can be found in Ref. [30].Both the inner grid and anode planes have every eighth wire joined together and read out as one, such that a single 'octave' of wires reads out 8 × 2 = 16 mm in x and y: large enough to contain the recoil events of interest. The outermost 52 (41) wires of the 512 total on the inner grid (anode) planes are grouped together into x (y) veto regions, reducing the fiducial volume of the detector to 0.80 m 3 . The anode and grid veto signal...

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“…The final NIPs value for the event is the sum Table 1: NIPs yield as a function of energy for fluorine recoils, from Ref. [35].…”

Section: Discussionmentioning

confidence: 99%

Section: Nuclear Recoil Efficiencymentioning

confidence: 99%

“…The top axis gives nuclear recoil energy as inferred from Ref. [35]. Fluorine recoil energy (keV) Figure 4: An efficiency map for recoil detection including all analysis cuts.…”

Section: Wimp Recoil Simulation and Limitsmentioning

confidence: 99%

Section: Wimp Recoil Simulation and Limitsmentioning

confidence: 99%

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First background-free limit from a directional dark matter experiment: Results from a fully fiducialised DRIFT detector

Battat

Brack

Daw

et al. 2015

Physics of the Dark Universe

105

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show abstract

“…This gas quenching factor measures the fraction of energy that goes into ionization for a given recoil. For example, the quenching factor is 0.53 for a 50 keV fluorine recoil in a 30:10 Torr of CS 2 :CF 4 gas mixture, and so a recoil of this energy will produce 1055 electron-ion pairs [29,34].…”

Section: Discussionmentioning

confidence: 99%

First measurement of nuclear recoil head-tail sense in a fiducialised WIMP dark matter detector

et al. 2016

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Recent computational results suggest that directional dark matter detectors have potential to probe for WIMP dark matter particles below the neutrino floor. The DRIFT-IId detector used in this work is a leading directional WIMP search time projection chamber detector. We report the first measurements of the detection of the directional nuclear recoils in a fully fiducialised lowpressure time projection chamber. In this new operational mode, the distance between each event vertex and the readout plane is determined by the measurement of minority carriers produced by adding a small amount of oxygen to the nominal CS 2 +CF 4 target gas mixture. The CS 2 +CF 4 +O 2 mixture has been shown to enable background-free operation at current sensitivities. Sulfur, fluorine, and carbon recoils were generated using neutrons emitted from a 252 Cf source positioned at different locations around the detector. Measurement of the relative energy loss along the recoil tracks allowed the track vector sense, or the so-called head-tail asymmetry parameter, to be deduced. Results show that the previously reported observation of head-tail sensitivity in pure CS 2 is well retained after the addition of oxygen to the gas mixture.

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High power THz source based on coherent radiation of picosecond relativistic electron bunch train

You

Yan

et al. 2011

Sci. China Phys. Mech. Astron.

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Bragg-like curve for dark matter searches: Binary gases

Cited by 28 publications

References 17 publications

First background-free limit from a directional dark matter experiment: Results from a fully fiducialised DRIFT detector

First background-free limit from a directional dark matter experiment: Results from a fully fiducialised DRIFT detector

First measurement of nuclear recoil head-tail sense in a fiducialised WIMP dark matter detector

High power THz source based on coherent radiation of picosecond relativistic electron bunch train

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