The EBEX Cryostat and Supporting Electronics

TL;DR

The paper details the design, implementation, and successful testing of the cryostat and electronics system for the EBEX balloon-borne polarimeter, crucial for measuring cosmic microwave background polarization.

Contribution

It presents the first comprehensive description of EBEX's cryostat and electronics, including their performance during an engineering test flight.

Findings

Cryostat temperatures remained stable during testing.

No scan synchronous signals detected in cryostat temperatures.

Electronics effectively monitored and controlled the cryogenic system.

Abstract

We describe the cryostat and supporting electronics for the EBEX experiment. EBEX is a balloon-borne polarimeter designed to measure the B-mode polarization of the cosmic microwave background radiation. The instrument includes a 1.5 meter Gregorian-type telescope and 1432 bolometric transition edge sensor detectors operating at 0.3 K. Electronics for monitoring temperatures and controlling cryostat refrigerators is read out over CANbus. A timing system ensures the data from all subsystems is accurately synchronized. EBEX completed an engineering test flight in June 2009 during which the cryogenics and supporting electronics performed according to predictions. The temperatures of the cryostat were stable, and an analysis of a subset of the data finds no scan synchronous signal in the cryostat temperatures. Preparations are underway for an Antarctic flight.