Construction of the Event Plane Detector at Star Experiment
Te-Chuan Huang1*
1Department of physics, National Cheng Kung University, Tainan, Taiwan
* Presenter:Te-Chuan Huang,
The Event Plane Detector (EPD) is an important upgrade to the STAR experiment. It’s concept is similar to the Beam Beam Counter (BBC) which has been used in STAR since the beginning. EPD has the advantages over BBC in providing more pseudorapidity coverage (2.1 < |η| < 5.1 compared to 3.3 < |η| < 5.0) and higher granularity (744 distinct channels compared to 32), and these lead to an increase in first-order event plane resolution by a factor of at least 1.5. In addition, EPD can also provide TPC-independent event planes and centrality determination.
The EPD is a set of disks consisting of 1.2cm-thick scintillator tiles optically isolated with reflective epoxy and embedded with wavelength-shifting fibers held in place with optical epoxy which are coupled to silicon photomultipliers (SiPM) via clear optical fibers. The detector was constructed in π/6 azimuthal sections called supersectors, each of which were tested for tile quality with cosmic rays and tile crosstalk with a radioactive source.
In this talk, I will present the construction of EPD as well as several tests to characterize the qualities of supersectors.

Keywords: STAR, event plane, heavy ion, beam energy scan, centrality