A 1 GHz RF Trigger Unit implemented in FPGA logic

Applications of Trigger Units (TU) can be found in almost all accelerators at CERN. The requirements in terms of operating frequencies, configuration or modes of operation change from one application to another, how-ever, in terms of design requirements for the Trigger Unit, the operating frequency is probably the most demanding one. In this work, we present an implementation of a Trigger Unit almost fully embedded in the FPGA logic operating at a maximum frequency of 1 GHz using the internal serializer/deserializer circuitry to simplify the timing constraints of the design. This implementation allows easy reconfiguration of the module and the development of new modes of operation, which are described in this paper.Comment: Poster presented at LLRF Workshop 2017 (LLRF2017, arXiv:1803.07677

Determination of the modes in two types of closed circuits with quantum tunneling

Others have solved the Schr\"odinger equation for a one-dimensional model having a square potential barrier in free-space by requiring an incident and a reflected wave in the semi-infinite pre-barrier region, two opposing waves in the square barrier, and a transmitted wave in the semi-infinite post-barrier region. Now we model a pre-barrier region having finite length that is shunted by the barrier to form a closed circuit. We use the boundary condition that the wavefunction and its derivative are continuous at the both ends of this model to obtain a homogeneous matrix equation. Thus, the determinant must be zero for a non-trivial solution. All but one of the following four parameters are specified and the remaining one is varied to bring the determinant to zero for a solution: (1) the electron energy, (2) the barrier length, (3) the barrier height, and (4) the pre-barrier length. The solutions with a square barrier are sets of non-intersecting S-shaped lines in the four-parameter space. The solutions with a triangular barrier have the product of the propagation constant and the length of the pre-barrier region as integer multiples of two-pi radians. Only static solutions are considered, but this method could be applied to time-dependent cases under quasistatic conditions. Suggestions are given for the design and testing of prototypes.Comment: 11 pages, 2 tables, no figure

Can one predict DNA Transcription Start Sites by studying bubbles?

It has been speculated that bubble formation of several base-pairs due to thermal fluctuations is indicatory for biological active sites. Recent evidence, based on experiments and molecular dynamics (MD) simulations using the Peyrard-Bishop-Dauxois model, seems to point in this direction. However, sufficiently large bubbles appear only seldom which makes an accurate calculation difficult even for minimal models. In this letter, we introduce a new method that is orders of magnitude faster than MD. Using this method we show that the present evidence is unsubstantiated.Comment: 4 pages, 3 figures, accepted for publication in physical review letter

Error and Attack Tolerance of Layered Complex Networks

Many complex systems may be described not by one, but by a number of complex networks mapped one on the other in a multilayer structure. The interactions and dependencies between these layers cause that what is true for a distinct single layer does not necessarily reflect well the state of the entire system. In this paper we study the robustness of three real-life examples of two-layer complex systems that come from the fields of communication (the Internet), transportation (the European railway system) and biology (the human brain). In order to cover the whole range of features specific to these systems, we focus on two extreme policies of system's response to failures, no rerouting and full rerouting. Our main finding is that multilayer systems are much more vulnerable to errors and intentional attacks than they seem to be from a single layer perspective.Comment: 5 pages, 3 figure

Apparatus for measuring high frequency currents

An apparatus for measuring high frequency currents includes a non-ferrous core current probe that is coupled to a wide-band transimpedance amplifier. The current probe has a secondary winding with a winding resistance that is substantially smaller than the reactance of the winding. The sensitivity of the current probe is substantially flat over a wide band of frequencies. The apparatus is particularly useful for measuring exposure of humans to radio frequency currents