A new detector exploiting the technology of Gas Electron Multipliers is under construction to replace the innermost drift chamber of BESIII experiment, since its efficiency is compromised owing the high luminosity of Beijing Electron Positron Collider. The new inner tracker with a cylindrical shape will deploy several new features. The analogue readout and two complementary algorithms to reconstruct the position will allow achieving a spatial resolution of 130 µm in a 1 T magnetic field. For this purpose, TIGER, a new custom 64-channel ASIC, providing time and charge measurements, has been developed. Here, a summary of the most recent results on detector and electronics prototypes is given.

Gas detectors are one of the pillars of the research in fundamental physics. Since several years, a new concept of detectors, called Micro Pattern Gas Detectors (MPGD), allows to overcome many of the problems of other types of commonly used detectors, like drift chambers and microstrip detectors, reducing the discharge rate and increasing the radiation tolerance. Among these, one of the most commonly used is the Gas Electron Multiplier (GEM). GEMs have become an important reality for fundamental physics detectors. Commonly deployed as fast timing detectors and triggers, due to their fast response, high rate capability and high radiation hardness, they can also be used as trackers. The readout scheme is one of the most important features in tracking technology. The center of gravity technique allows to overcome the limit of the digital pads, whose spatial resolution is constrained by the pitch dimension. The presence of a high external magnetic field can distort the electronic cloud and affect the spatial resolution. The micro-TPC (µ−TPC) reconstruction method allows to reconstruct the three dimensional particle position as in a traditional Time Projection Chamber, but within a drift gap of a few millimeters. This method brings these detectors into a new perspective for what concerns the spatial resolution in strong magnetic field. In this report, the basis of this new technique will be shown and it will be compared to the traditional center of gravity. The results of a series of test beam performed with 10×10 cm 2 planar prototypes in magnetic field will also be presented. This is one of the first implementations of this technique for GEM detectors in magnetic field and allows to reach unprecedented performance for gas detectors, up to a limit of 120 µm at 1 T, one of the world's best results for MPGDs in strong magnetic field. The µ−TPC reconstruction has been recently tested at very high rates in a test beam at the MAMI facility; preliminary results of the test will be presented.

The Jülich Electric Dipole moment Investigation (JEDI) collaboration aims at a direct measurement of the Electric Dipole Moment (EDM) of protons and deuterons using a storage ring. The measurement is based on a polarization measurement. In order to reach highest accuracy, one has to know the exact trajectory through the magnets, especially the quadrupoles, to avoid the influence of magnetic fields on the polarization vector. In this paper, the development of a beam-based alignment technique is described that was developed and implemented at the COoler SYnchrotron (COSY) at Forschungszentrum Jülich. Well aligned quadrupoles permit one to absolutely calibrate the Beam Position Monitors (BPMs). The method is based on the fact that a particle beam, which does not pass through the center of a quadrupole, experiences a deflection. The precision reached by the method is approximately 40μm. Some consequences for the design of a new high precision storage ring for EDM mesasurements are discussed.

A new inner tracker based on a cylindrical gas electron-multiplier detector is under development to replace the current inner drift chamber of the BES III spectrometer. The BES III experiment is carried out at the BEPC II e[Formula: see text]e[Formula: see text] collider in Beijing at center-of-mass energies in the tau-charm region with a design luminosity of 1.0 [Formula: see text] 10[Formula: see text] cm[Formula: see text]s[Formula: see text]. The new inner tracker consists of three cylindrical layers of triple GEM surrounding the interaction point, covering 93% of solid angle. To fulfill physics requirements, a spatial resolution of 130 μm must be achieved. Both planar and cylindrical prototypes have been built and tested. A custom ASIC using UMC 110-nm technology has been designed to provide charge and time measurements—the first prototype is in testing. Notable and innovative aspects of the new inner tracker and the performance of the detector prototypes and readout ASIC are reported here.

A calorimetric polarimeter based on inorganic LYSO scintillators is described. It has been designed for use in a storage ring to search for electric dipole moments (EDM) of charged particles such as the proton and deuteron. Its development and first use was on the Cooler Synchrotron (COSY) at the Forschungszentrum Jülich with 0.97 GeV/c polarized deuterons, a particle and energy suitable for an EDM search. The search requires a polarimeter with high efficiency, large analyzing power, and stable operating characteristics. With typical beam momenta of about 1 GeV/c, the scattering of protons or deuterons from a carbon target into forward angles becomes a nearly optimal choice of an analyzing reaction. The polarimeter described here consists of 52 LYSO detector modules, arranged in 4 symmetric blocks (up, down, left, right) for energy determination behind plastic scintillators for particle identification via energy loss. The commissioning results of the current setup demonstrate that the polarimeter is ready to be employed in a first direct measurement for an EDM on the deuteron, which is planned at COSY.