LARES/WEBER-SAT and the equivalence principle

It has often been claimed that the proposed Earth artificial satellite LARES/WEBER-SAT-whose primary goal is, in fact, the measurement of the general relativistic Lense-Thirring effect at a some percent level-would allow to greatly improve, among (many) other things, the present-day (10^-13) level of accuracy in testing the equivalence principle as well. Recent claims point towards even two orders of magnitude better, i.e. 10^-15. In this note we show that such a goal is, in fact, unattainable by many orders of magnitude being, instead, the achievable level of the order of 10^-9.Comment: LaTex, 4 pages, no figures, no tables, 26 references. Proofs corrections included. To appear in EPL (Europhysics Letters

Test beam measurement of the first prototype of the fast silicon pixel monolithic detector for the TT-PET project

The TT-PET collaboration is developing a PET scanner for small animals with 30 ps time-of-flight resolution and sub-millimetre 3D detection granularity. The sensitive element of the scanner is a monolithic silicon pixel detector based on state-of-the-art SiGe BiCMOS technology. The first ASIC prototype for the TT-PET was produced and tested in the laboratory and with minimum ionizing particles. The electronics exhibit an equivalent noise charge below 600 e- RMS and a pulse rise time of less than 2 ns, in accordance with the simulations. The pixels with a capacitance of 0.8 pF were measured to have a detection efficiency greater than 99% and, although in the absence of the post-processing, a time resolution of approximately 200 ps

Material and Manufacturing of LARES Satellite

Differently from all other laser ranged satellites, LARES is manufactured from a single piece bulk material. This choice offers a simpler design and will reduce thermal gradients on the satellite surface. To improve the surface-to-mass ratio, i.e., a parameter proportional to the intensity of most of the non gravitational perturbations, a high density material has been selected: tungsten alloy. A combination of data from two more satellites and a design of LARES aimed to reduce the non gravitational perturbations will allow the measurement of the Lense-Thirring effect with an accuracy never reached before. This effect is predicted by Einstein General Relativity. Tungsten alloys have never been used for the entire construction of a satellite. For this reason a first breadboard, representative of a small portion of the satellite has been manufactured. This allowed to pin point a problem with the small screws of the cube corner reflector mounting system. After a description of the material and the procured semi-finished parts, particular interest will be devoted to the manufacturing process for the screws and to the microscopic analysis of the tungsten alloy screws that broke during mounting. A different manufacturing process for the screw is finally proposed

The relativistic precession of the orbits

The relativistic precession can be quickly inferred from the nonlinear polar orbit equation without actually solving it.Comment: Accepted for publication in Astrophysics & Space Scienc

A Novel Approach for an Integrated Straw tube-Microstrip Detector

We report on a novel concept of silicon microstrips and straw tubes detector, where integration is accomplished by a straw module with straws not subjected to mechanical tension in a Rohacell $^{\circledR}$ lattice and carbon fiber reinforced plastic shell. Results on mechanical and test beam performances are reported on as well.Comment: Accepted by Transactions on Nuclear Science (2005). 11 pages, 9 figures, uses lnfprep.st

Novel high-speed monolithic silicon detector for particle physics

This contribution presents simulation results, implementation, and first tests of a monolithic detector developed at KIT. It consists of a sensor diode tightly integrated with an analogue front-end based on SiGe (Silicon-Germanium) SG13G2 130 nm BiCMOS technology produced at the Leibniz Institute for High Performance Microelectronics (IHP). The pixel size is 100 μm × 100 μm, and the nwell charge collection node dimensions were reduced to 10 μm × 10 μm. We investigate the influence of this approach on sensor performance, spatial resolution via charge sharing and timing behaviour

A monolithic ASIC demonstrator for the Thin Time-of-Flight PET scanner

Time-of-flight measurement is an important advancement in PET scanners to improve image reconstruction with a lower delivered radiation dose. This article describes the monolithic ASIC for the TT-PET project, a novel idea for a high-precision PET scanner for small animals. The chip uses a SiGe Bi-CMOS process for timing measurements, integrating a fully-depleted pixel matrix with a low-power BJT-based front-end per channel, integrated on the same 100 µm thick die. The target timing resolution of the scanner is 30 ps RMS for electrons from the conversion of 511 keV photons. The system will include 1.6 million channels across almost 2000 different chips. A full-featured demonstrator chip with a 3×10 matrix of 500×500 µm2 pixels was fabricated to validate each block. Its design and experimental results are presented here. © 2019 CERN

An analysis of materials used in the RPC detector and in the closed loop gas system of CMS at the LHC.

The results are reported of the study of materials used in the CERN Closed Loop recirculation gas system currently under test with the RPC muon detectors in the CMS experiment at the LHC. Studies include a sampling campaign in a low-radiation environment (cosmic rays at the CERN ISR test site). We describe the dedicated RPC chamber tests, the chemical analysis of the filters and gas used, and discuss the results of the Closed Loop system