A
bstract
FASER is one of the promising experiments which search for long-lived particles beyond the Standard Model. In this paper, we focus on dark photon associating with an additional U(1) gauge ...symmetry, and also a scalar boson breaking this U(1) gauge symmetry. We study the sensitivity to the dark photon originated from U(1)-breaking scalar decays. We find that a sizable number of dark photon signatures can be expected in wider parameter space than previous studies.
Figure 1. Expected number of the signal events of the dark photon after correcting the
ϕ
decay width. We have found a mistake in calculations of the expected number of the signal events shown in ...figure 2, 4 and 5 of our paper.
Radiation-tolerant n+-in-p silicon sensors were developed for use in very high radiation environments. Novel n+-in-p silicon strip and pixel sensors and test structures were fabricated, tested and ...evaluated, in order to understand the designs implemented. The resistance between the n+ implants (interstrip resistance), the electric potential of the p-stop, and the punch-through-protection (PTP) onset voltage were measured before and as a function of fluence after irradiation. The technology computer-aided design (TCAD) simulations were used to understand the radiation damage and fluence dependence of the structures. The decrease in the interstrip resistance is a consequence of increased leakage current. The decrease in the electric potential of the p-stop results from a build-up of positive charge in the silicon–silicon oxide interface. The decrease and subsequent increase in the PTP onset voltages results from the interface charge build-up and an increase in acceptor states.
Development of readout system for FE-I4 pixel module using SiTCP Teoh, J.J.; Hanagaki, K.; Ikegami, Y. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2013, Letnik:
731
Journal Article
Recenzirano
The ATLAS pixel detector will be replaced in the future High Luminosity-Large Hadron Collider (HL-LHC) upgrade to preserve or improve the detector performance at high luminosity environment. To meet ...the tight requirements of the upgrade, a new pixel Front-End (FE) Integrated Circuit (IC) called FE-I4 has been developed. We have then devised a readout system for the new FE IC. Our system incorporates Silicon Transmission Control Protocol (SiTCP) technology (Uchida, 2008 1) which utilizes the standard TCP/IP and UDP communication protocols. This technology allows direct data access and transfer between a readout hardware chain and PC via a high speed Ethernet. In addition, the communication protocols are small enough to be implemented in a single Field-Programable Gate Array (FPGA). Relying on this technology, we have been able to construct a very compact, versatile and fast readout system. We have developed a firmware and software together with the readout hardware chain. We also have established basic functionalities for reading out FE-I4.
Planar geometry silicon pixel and strip sensors for the high luminosity upgrade of the LHC (HL-LHC) require a high bias voltage of 1000V in order to withstand a radiation damage caused by particle ...fluences of 1×1016 1MeVneq/cm2 and 1×1015 1MeVneq/cm2 for pixel and strip detectors, respectively. In order to minimize the inactive edge space that can withstand a bias voltage of 1000V, edge regions susceptible to microdischarge (MD) should be carefully optimized. We fabricated diodes with various edge distances (slim-edge diodes) and with 1–3 multiple guard rings (multi-guard diodes). AC coupling insulators of strip sensors are vulnerable to sudden heavy charge deposition, such as an accidental beam splash, which may destroy the readout AC capacitors. Thus various types of punch-through-protection (PTP) structures were implemented in order to find the most effective structure to protect against heavy charge deposition. These samples were irradiated with 70MeV protons at fluences of 5×1012 1MeVneq/cm2–1×1016 1MeVneq/cm2. Their performances were evaluated before and after irradiation in terms of an onset voltage of the MD, a turn-on voltage of the PTP, and PTP saturation resistance.
► We have evaluated radiation tolerance of n-in-p sensors up to 1×1016 1MeVneq/cm2. ► Both n-bulk and p-bulk require a field width≥450μm in order to withstand 1000V. ► The MD onset voltage was found to be independent of the edge width. ► With increasing number of guard rings, bias voltage tolerance improved before irrad. ► BZ4D-5 (with full extension) performs the best among the samples.
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