RTS: Graphene FET particle detectors for directional detection of MeV dark matter
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US/Central
Sunrise (WH11NE) (Fermilab)
Sunrise (WH11NE)
Fermilab
Description
Graphene field-effect transistors (G-FETs) made from nanoribbons provide tunable meV band gap devices and may have unprecedented sensitivity to low energy electron recoils. G-FET arrays have the possibility of high-granularity, low-mass particle tracking and a fiducialized volume of stacked planar arrays. In this proposal we look for MeV dark matter scattering events that liberate an electron from the graphene target. A narrow, vacuum-separated front-gate of the G-FET imposes a kinematic discrimination on the maximum electron recoil energy, and the FET-to-FET hopping trajectory of an ejected electron indicates the scattering direction, shown to be correlated to the dark matter wind [Hochberg, et. al, 2016. ``Directional Detection of Dark Matter with 2D Targets", http://arxiv.org/abs/1606.08849]. Initial device characterization will be presented. A scalable wafer-level process is being developed, with individually vacuum-sealed compartments, and integrated flexible polyimide cables connected to a low-noise transistor bank readout. Plans for underground evaluation of the background-levels will also be presented.
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Graphene FET particle detectors for directional detection of MeV dark matter