SuperCDMS Cold Hardware Design

Abstract

We discuss the current design of the cold hardware and cold electronics to be used in the upcoming SuperCDMS Soudan deployment. Engineering challenges associated with such concerns as thermal isolation, microphonics, radiopurity, and power dissipation are discussed, along with identifying the design changes necessary for SuperCDMS SNOLAB. The Cryogenic Dark Matter Search (CDMS) employs ultrapure 1-inch thick, 3-inch diameter germanium crystals operating below 50 mK in a dilution cryostat. These detectors give an ionization and phonon signal, which gives us rejection capabilities regarding background events versus dark matter signals.

Simulation of the Charge Measurements for the SuperCDMS Soudan Experiment

“…The charge collection elements are commonly referred to as FET sensors, even though inaccurate (because the sensing device is simply the electrode), it is because the amplifier circuit uses a junction Field-Effect Transistor [42,55]. The individual charge collection response is combined into two channels on each side, denoted inner and outer [42], given their radial partition, as seen in Figure 2.5.…”

“…The charge collection readout waveform is created when charges reach the the electrodes which are part of an amplifying circuit, as shown in Figure 3.5. The combination of compo-nents designed to be very efficient for driving low-power, low-noise signals [55], can operate at low temperature, and is located in the cold electronics of the towers, near the detectors.…”