Speaker
Dr
Marcos Turqueti
(L)
Description
LBNL has developed an innovative data acquisition module for superconductive magnets where the front-end electronics and digitizer resides inside the cryostat. Currently, in most cases, the digitization of signals internal to the cryostat containing the superconducting magnet is done outside the cryostat. This kind of setup can degrade the performance of the data acquisition in several ways, and add complexity to the system that increases with the number of monitored signals.
The system described in this work allows conventional electronic technologies such as enhanced metal–oxide–semiconductors to work inside cryostats at temperatures as low as 4.2K. This is achieved by a combination of careful active management of heat inside the module that keeps the electronic package at approximately 77K, and the use of very low power active components. This approach avoids all difficulties that arise from changes in carrier mobility that occurs in semiconductors at deep cryogenic temperature.
A significant reduction in electrical noise from signals captured inside the cryostat occurs due to the low temperature environment that the electronics is immersed in, reducing the thermal noise. The shorter distance that signals are transmitted before digitization reduces pickup, and cross-talk between channels. Another important advantage is the simplification of the feedthrough interface on the magnet head. All lines coming out of the cryostat are digital and low voltage, reducing the possibility of discharges inside the cryostat.
This paper will explain in details the architecture, and inner workings of this electronic system. It will also show results on the performance of the Analog to Digital Converter (ADC) when the system is immersed in a cryostat at 4.2K, and at 77K. Parameters such as power dissipation, integral non-linearity, effective number of bits, signal-to-noise and distortion, will all be presented for both temperatures.
Primary author
Dr
Marcos Turqueti
(L)
Co-authors
Robert Albright
(LBNL)
Dr
Soren Prestemon
(LBNL)
