A photomultipler tube is submerged in liquid argon

Taritree's Athena Space

I study the neutrino, one of the fundamental particles of the Standard Model. The neutrino is extremely light and weakly interacting. So weak, in fact, that it can pass through a light-years long block of lead without striking it. As a result, neutrino experiments need to build massive, building-sized detectors to study the particle. However, the effort is worth it, as there are a number of ways the neutrino can help us look for new laws of physics. Below are a number of projects I work on with that end in mind.

MicroBooNE

MicroBooNE is an neutrino experiment at Fermi National Laboratory that will look for the possible existance of new physics beyond the Standard Model. One way it will do this will be to study precisely how a beam of neutrinos of a certain type (from muon neutrinos) changes into another (to electon neutrinos). The detector technology MicroBooNE employs, Liquid Argon Time projection chambers, provide very high-resolution images of the interactions. This allows it to remove certain backgrounds more efficiently than previous experiments.

A picture of inside the MicroBooNE cryostat. Photomultiplier tubes can be seen on the left wall.

NuDot

The fact that the neutrino has a small, but non-zero mass was a fact not predicted by the Standard Model. But now that we know the neutrino has mass, what is the proper way to describe massive neutrinos in our theories? The way to do this depends on whether the neutrino is a Dirac particle or a Majorana particle. If Majorana, then a nuclear-decay process known as neutrino-less double beta decay should be possible. I am working with Prof. Lindley Windlow to build a detector using quantum dot nancrystals to look for this as-of-yet-unobserved process.

Quantum dots can be suspended in organic solvents and, in response to UV, glow with a color determned by their size.

LArTPC R&D

MicroBooNE and other up-coming neutrino experiments use a detector known as a Liquid Argon TPC. This type of detector responds to particles interacting inside it by producing both charge and scintillation photons. While the techniques for reading out the charge are relatively well established, there is still lots of room for R&D on how to make use of the photons. I am currently working on devices to cheaply instrument the detectors while reading out as much light as possible.

An acrylic bar coated with Tetra-phenyl butadiene glows in response to UV light. The bar converts UV photons from the Liquid argon into blue light which our photodetectors can see.

GPU-Accelerated Photon Simulations

I am interested in using high performance computing techniques to help MicroBooNE and other neutrino experiments simulate the behavior of photons in the detectors. Using existing tools, Chroma (by S. Seibert) and G4DAE (by S. Blyth), photons in MicroBooNE can be simulated at a rate of about 950K photons/sec. The hope is to use this tool to help tune our optical simulation and maybe allow the photons to help reconstruct the interactions in the detector.