The Snowball Chamber: Using Supercooled Water to Search for Low-Mass Dark Matter*

The cloud and bubble chambers have historically been used for particle detection, capitalizing on supersaturation and superheating respectively. We present now on the snowball chamber, which utilizes a supercooled liquid. In our prototype, an incoming particle triggered crystallization of purified water. We demonstrate that water is supercooled for a significantly shorter time with respect to control data in the presence of AmBe and ²⁵²Cf neutron sources. A greater number of multiple nucleation sites are observed as well in neutron calibration data, as in a PICO bubble chamber. Similarly, gamma calibration data indicate a high degree of insensitivity to electron recoils inducing the phase transition, making this detector potentially ideal for dark matter searches seeking nuclear recoil alone. We will explore the possibility of using this new technology for that, updating the community on new results achieved since last year's APS meeting (April 2018).