A Current Monitor System in High-Voltage Applications in a Range from Picoamps to Microamps

• Main Authors: Rabí Soto-Camacho, Sergio Vergara-Limon, María Aurora Diozcora Vargas-Treviño, Guy Paic, Jesús López-Gómez, Marciano Vargas-Treviño, Jaime Gutierrez-Gutierrez, Fermín Martínez-Solis, Miguel Enrique Patiño-Salazar, Victor Manuel Velázquez-Aguilar
• Format: Article
• Language: English
• Published: MDPI AG 2021-01-01
• Series: Electronics
• Subjects: autoscale ammeter; current monitoring; data acquisition system; electromagnetic interference; electronics; gas electron multiplier
• Online Access: https://www.mdpi.com/2079-9292/10/2/164

In this article, we present a system to measure current in the range of 0 to 10 <inline-formula><math display="inline"><semantics><mi mathvariant="sans-serif">μ</mi></semantics></math></inline-formula>A with high-voltage isolation up to 5 kV. This current monitor consists of three ammeters connected in series, to improve the resolution in the measurement. The design features several innovative elements such as using low voltage to provide power to the devices to measure the current and digitize it with a sampling frequency of 1 KHz, it is generated based on a DC-DC converter that produces three voltages, +12 V, −12 V, and 5 V, from a conventional 10 V source. The three voltages are referenced to the same floating ground. The DC-DC converter has a high voltage insulation up to 5 kV and four optocouplers with an insulation up to 20 kV are used to read the digitized data. The introduction of a DC-DC converter contributed to reduce the noise level in the analog part of the circuit which has been resolved implementing shields inside the board. In particle physics, several systems are used to detect particles in high-energy physics experiments such as Gas Electron Multiplier (GEM), micromegas, etc. GEMs suffer small deteriorations due to discharges in constant operation and require monitoring the current consumption at high frequency (1 kHz). In this work, we present the design and operation of a 0 to 10 <inline-formula><math display="inline"><semantics><mi mathvariant="sans-serif">μ</mi></semantics></math></inline-formula>A auto scale ammeter. The results obtained by monitoring the current in a 10 × 10 cm<inline-formula><math display="inline"><semantics><msup><mrow></mrow><mn>2</mn></msup></semantics></math></inline-formula> GEM are shown.