Speaker
Dr
ILARIA BALOSSINO
(INFN Ferrara - IHEP)
Description
Gas Electron Multipliers (GEMs) can be produced in large foils and molded
in different shapes. The possibility to create cylindrical layers has
opened the opportunity to use such detector as internal trackers at
collider experiments. One crucial item is to have low material budget in
the active area, so the supporting structure of anode and cathode must be
light.
KLOE2 collaboration has built the first Cylindrical GEM detector with
honeycomb material with carbon fiber skins produced at high temperature.
BESIII is preparing an innovative CGEM detector with charge and time
readout. Among several innovative features, the mechanical structure was
designed to be a sandwich of kapton and Rohacell, a PMI foam. After the
transportation of the prototypes from the construction site in Italy to
the Institute of High Energy Physics in Beijing, some malfunctions have
been observed in some prototypes, compatible with GEMs deformation inside
the detector.
We have performed a detailed study by means of an industrial CT scan
available in IHEP lab and autopsy to the damaged detectors. In this talk,
we will review the construction process, the shipment, the findings of the
investigation.
A new supporting structure of carbon fiber and honeycomb, assembled at
room temperature, has been designed and developed. The thickness of the
carbon fiber is small enough to keep the material budget of a single
detector layer below 0.5% of a radiation length, while the mechanical
robustness results beyond the purpose of a detector for HEP.
A first detector with such a mechanical structure has been built and
shipped to IHEP, preliminary results from operation (e.g. current
stability, discharges, temperature and humidity correlation) of the
detectors will be also presented in this talk.
Primary author
Dr
ILARIA BALOSSINO
(INFN Ferrara - IHEP)
