24-28 February 2020
Budker Institute of Nuclear Physics
Asia/Novosibirsk timezone

A 10-3 drift velocity monitoring chamber

Not scheduled
Budker Institute of Nuclear Physics

Budker Institute of Nuclear Physics

11, akademika Lavrentieva prospect, Novosibirsk, Russia
Board: 92
Poster Tracking and vertex detectors


Federica Cuna (Università del Salento and INFN Lecce)


The MEG-II experiment searches for the lepton flavor violating decay μ→e+γ . The reconstruction of the positron trajectory uses a cylindrical drift chamber operated with a mixture of He and i-C4H10 gas. It is important to provide a stable performance of the detector in terms of its electron transport parameters, avalanche multiplication, composition and purity of the gas mixture. In order to have a continuous monitoring of the quality of gas, we plan to install a small drift chamber, with a simple geometry that allows to measure very precisely and in a promptly the electron drift velocity, the most sensitive parameter to the gas mixture. The monitoring chamber will be supplied with gas coming from the inlet and from the outlet of the detector to determine if gas contaminations originate inside the main chamber or in the gas supply system. The chamber is a small box with cathode walls, defining a highly uniform electric field in the volume of two adjacent drift cells. In the plane separating the two drift cells, 4 sense wires alternated with 5 guard wires collect the drifting electrons. The trigger is provided by two 90Sr weak calibration radioactive sources placed on top of a two thin scintillator tiles telescope. The whole system is designed to give a prompt response (within a minute) about drift velocity variations at the 10-3 level. Such a variation correspond to: - +0.4% in i-C4H10 content (from 10.0% to 10.4%) - -0.2% in i-C4H10 content (from 10.0% to 9.8%) - ±0.4% in E/p (≈6% in gas gain) at gain≈ 5x105 - ±4 V at p≈1 bar, T≈25 °C - ±4 mbar at V≈1500V, T≈25 °C - -0.3 °C at p≈1 bar, V≈1500 V - ≤100 ppm variations in water vapor content around 3500 ppm.

Primary author

Federica Cuna (Università del Salento and INFN Lecce)


Alessandro Corvaglia (INFN Lecce) Alessandro Miccoli (INFN Lecce) Dr Francesco Grancagnolo (INFN) Mr Gianluigi Chiarello (INFN Roma1) Dr Giovanni Francesco Tassielli (INFN Lecce & University of Salento) Prof. Marco Panareo (INFN - Lecce) Mariachiara Manta (Università del Salento) Nicola De Filippis (Politecnico di Bari e INFN Bari)

Presentation Materials