相对论重离子碰撞的目的是在实验室情况下研究有限温度密度下的QCD物质性质。RHIC 和LHC多年的实验表明，在高能量的重离子碰撞中可能形成了一种强耦合的夸克胶子物质(QGP)，这些实验结果大多数都来自于对末态强子的测量，因此可能受到系统演化过程强相互作用影响。电磁探针(如:双轻子)不参与强相互作用,能够逃离碰撞产生的强相互作用介质而不受影响，因此能够反映碰撞系统最干净，最直接的信息。但是重味夸克粒子衰变的双轻子为实验测量带来了大量的背景，因此对双轻子更进一步的测量首先要解决的就是这些重味夸克的贡献。在RHIC-STAR已有的双轻子研究的基础上，通过探测器的升级 - 重味夸克探测器(HFT)以及缪子探测器(MTD)，能够实现对重味夸克衰变的双轻子测量，从而通过双轻子的测量来研究重离子碰撞介质的各种性质，寻找夸克胶子热辐射。

The mission of ultra-relativistic heavy ion program is to study the QCD matter at finite temperature and density in laboratory. Probes that have been explored in experiments are mostly hadrons, which have been used to demonstrate the formation of strong-coupling Quark Gluon Plasma (sQGP) in the RHIC and LHC heavy ion collisions. Electromagnetic probes (e.g. dileptons, photons) can escape from the system without further strong interaction once they are produced. Therefore they can offer clean information on various stages during the whole system evolution. Especially, the dileptons in the low mass region are useful tools to study the chiral symmetry related physics, and the dileptons in the intermediate mass region are excepted to have significant contributions from the QGP thermal radiation. But there are huge background coming from the charm hadron semi-lepton decay, then the first step to measure the QGP thermal radiation and study the chiral symmetry related physics is to measure these charm hadron semi-lepton decay dilepton contribution precisely. Based on the RHIC-STAR experiment, with the STAR detectors upgrades Heavy Flavor Tracker(HFT) and Muon Telescope Detector(MTD), we will be able to measure the dielectron spectra with charm hardon decayed dielectron background subtracted. Then it will give us the possibility to measure the QGP thermal radiation.