A novel electrical method to measure wire tensions for time projection chambers

• Published in: Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Accelerators, spectrometers, detectors and associated equipment, 2019-01, Vol.915, p.75-81
• Main Authors: Garcia-Gamez, Diego, Basque, Vincent, Brooks, Thomas G., Evans, Justin J., Perry, Michael, Söldner-Rembold, Stefan, Spagliardi, Fabio, Szelc, Andrzej M.
• Format: Article
• Language: English
• Subjects: APA; Electrical; LArTPC; Wire tension
• ISSN: 0168-9002; 1872-9576
• DOI: 10.1016/j.nima.2018.09.031

We present a novel electrical technique to measure the tension of wires in multi-wire drift chambers. We create alternating electric fields by biasing adjacent wires on both sides of a test wire with a superposition of positive and negative DC voltages on an AC signal (VAC±VDC). The resulting oscillations of the wire will display a resonance at its natural frequency, and the corresponding change of the capacitance will lead to a measurable current. This scheme is scalable to multiple wires and therefore enables us to precisely measure the tension of a large number of wires in a short time. This technique can also be applied at cryogenic temperatures making it an attractive solution for future large time-projection chambers such as the DUNE detector. We present the concept, an example implementation and its performance in a real-world scenario and discuss the limitations of the sensitivity of the system in terms of voltage and wire length.