A Machine Learning Approach for the Tune Estimation in the LHC

The betatron tune in the Large Hadron Collider (LHC) is measured using a Base-Band Tune (BBQ) system. The processing of these BBQ signals is often perturbed by 50 Hz noise harmonics present in the beam. This causes the tune measurement algorithm, currently based on peak detection, to provide incorrect tune estimates during the acceleration cycle with values that oscillate between neighbouring harmonics. The LHC tune feedback (QFB) cannot be used to its full extent in these conditions as it relies on stable and reliable tune estimates. In this work, we propose new tune estimation algorithms, designed to mitigate this problem through different techniques. As ground-truth of the real tune measurement does not exist, we developed a surrogate model, which allowed us to perform a comparative analysis of a simple weighted moving average, Gaussian Processes and different deep learning techniques. The simulated dataset used to train the deep models was also improved using a variant of Generative Adversarial Networks (GANs) called SimGAN. In addition, we demonstrate how these methods perform with respect to the present tune estimation algorithm.

A Machine Learning Approach for the Tune Estimation in the LHC

The betatron tune in the Large Hadron Collider (LHC) is measured using a Base-Band Tune (BBQ) system. The processing of these BBQ signals is often perturbed by 50 Hz noise harmonics present in the beam. This causes the tune measurement algorithm, currently based on peak detection, to provide incorrect tune estimates during the acceleration cycle with values that oscillate between neighbouring harmonics. The LHC tune feedback (QFB) cannot be used to its full extent in these conditions as it relies on stable and reliable tune estimates. In this work we propose new tune estimation algorithms, designed to mitigate this problem through different techniques. As ground-truth of the real tune measurement does not exist, we developed a surrogate model, which allowed us to perform a comparative analysis of a simple weighted moving average, Gaussian Processes and different deep learning techniques. The simulated dataset used to train the deep models was also improved using a variant of Generative Adversarial Networks (GANs) called SimGAN. In addition we demonstrate how these methods perform with respect to the present tune estimation algorithm.

Acceleration through Digital Communication: Theorizing on a Perceived Lack of Time

Digital communication between humans fundamentally changes the nature of communication. One inherent change is the acceleration of communication as a systematic change in societal life, particularly in the workplace. Often, the aim is to release time resources. However, the acceleration of communication also leads to the opposite: a lack of time. This paradoxical development can be based on an acceleration cycle whereby technologies seem to be a solution on the micro-level, but they are also a significant part of the problem on the meso-level.

A Numerical Investigation to Study Roughness Effects in Oscillatory Flows

Effects of roughness on the near-bed turbulence characteristics in oscillatory flows are studied by means of particle-resolved direct numerical simulations (DNS). Two particle sizes of diameter 375 and 125 in wall units corresponding to the large size gravel and the small size sand particle, respectively, in a very rough turbulent flow regime are reported. A double-averaging technique is employed to study the nature of the wake field, i.e., the spatial inhomogeneities at the roughness length scale. This introduced additional production and transport terms in double-averaged Reynolds stress budget, indicating alternate pathways of turbulent energy transfer mechanisms. Budgets of normal components of Reynolds stress reveal redistribution of energy from streamwise component to other two components and is attributed to the work of pressure in both flow cases. It is shown that the large diameter gravel particles significantly modulate the near-bed flow structures, leading to pronounced isotropization of the near-bed flow; while in the sand case, elongated horseshoe structures are found as a result of high shear rate. Effect of mean shear rate on the near-bed anisotropy is significant in the sand case, while it is minimal for the gravel-bed. Redistribution of energy in the gravel case showed reduced dependence on the flow oscillations, while for the sand particle it is more pronounced towards the end of an acceleration cycle.

EFFECTS OF ALIGNMENT ERRORS IN PROTON NON-SCALING FFAG ACCELERATORS

Non-scaling FFAGs have gained interest in the past decade for their potential application to charged particle therapy using proton and ion beams. However, linear ns-FFAGs naturally cross betatron resonances throughout acceleration. With an acceleration cycle of thousands rather than tens of turns, we find that resonance crossing produces severe orbit distortion in a linear proton/ion ns-FFAG in the presence of alignment errors. To overcome this, the PAMELA (Particle Accelerator for MEdicaL Applications) lattice design avoids resonance crossing with a non-linear ns-FFAG design. This design is outlined and a comparative analysis of alignment tolerances presented.

Vibratory Conveying by Non-Sinusoidal Excitation

A vibratory conveyor is essentially an inclined plane which is subjected to an acceleration cycle, conventionally sinusoidal. It is used to transport components or material. Usually rapid upward motion is desired. This paper presents the results of an investigation on the performance of a vibratory conveyor excited by two in-phase non-sinusoidal displacement cycles composed of the first two harmonics along the trough and perpendicular to it. Mean conveying velocity is found to be considerably larger than that of conventional vibratory conveyers if the proper amplitudes of the second harmonics are chosen.

Analog and Digital Analysis and Synthesis of Oscillatory Tracks

A vibratory feeder is essentially an inclined plane which is subjected to an acceleration cycle. It is used to transport components or material, after giving them the proper orientation or mixing. Usually rapid upward motion is desired. The purpose of this paper is to provide the designer with some basic tools that enable him to analyze, and effectively choose, the basic parameters pertaining to a vibratory feeder. Programs to solve specific cases are also included. The digital and analog approaches are used with equal emphasis whenever applicable.