Physics

The lateral resolution of an X-ray photoelectron spectroscopy instrument, which is equipped with a focused X-ray beam, is limited by the nominal X-ray beam diameter and the long tail intensity distri-bution of the X-ray beam. The long tail intensity distribution of the X-ray beam impedes to perform a measurement with good lateral resolution and low detection limits at the same time. Two experimental setups are described which allow examining sample structures that are smaller than the X-ray beam dimensions. The first method uses differential sample charging on partly non-conductive samples by low energy electron flooding. The spectra of the non-conductive sample areas are shifted towards lower binding energy. That way, the surface compositions of conductive and non-conductive sample areas are estimated independently. The second method utilizes the rather limited dimensions of the energy analyser acceptance volume. Here only the sample is placed inside the energy analyser acceptance volume. That way, signals from the illuminated sample contribute exclusively to the measured photoelectrons intensity, independent form the sample size.

The MATHUSLA detector to be installed on the surface above and somewhat displaced from the CMS interaction point (IP) will cover an area of 100×100 m 2 containing many layers of scintillators planes to establish the space and time coordinates of charged particle tracks. This is an unprecedented detector in terms of size and continuous sensitivity over an area of 10 4 m 2 . This document describes the present MATHUSLA detector concept that is sensitive to both long-lived particles produced in the LHC collisions in CMS and cosmic ray extended air showers (EAS). The ability to improve significantly cosmic ray studies by adding a 10 4 m 2 layer of RPCs that have both digital and analogue readout similar to the ARGO-YBJ experiment will be discussed with focus on large zenith angle EAS.

Electrical measurement of nano-scale devices and structures requires skills and hardware to make nano-contacts. Such measurements have been difficult for number of laboratories due to cost of probe station and nano-probes. In the present work, we have demonstrated possibility of assembling low cost probe station using USB microscope (US $ 30) coupled with in-house developed probe station. We have explored the effect of shape of etching electrodes on the geometry of the microprobes developed. The variation in the geometry of copper wire electrode is observed to affect the probe length (0.58 mm to 2.15 mm) and its half cone angle (1.4 to 8.8 degree). These developed probes were used to make contact on micro patterned metal films and was used for electrical measurement along with semiconductor parameter analyzer. These probes show low contact resistance ( 4 ohm) and follows ohmic behavior. Such probes can be used for laboratories involved in teaching and multidisciplinary research activities and Atomic Force Microscopy.

The sudden rise of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic early 2020 throughout the world has called into drastic action measures to do instant detection and reduce the spread rate. The common diagnostics testing methods has been only partially effective in satisfying the booming demand for fast detection methods to contain the further spread. However, the point-of-risk accurate diagnosis of this new emerging viral infection is paramount as simultaneous normal working operation and dealing with symptoms of SARS-CoV-2 can become the norm for years to come. Sensitive cost-effective biosensor with mass production capability is crucial throughout the world until a universal vaccination become available. Optical label-free biosensors can provide a non-invasive, extremely sensitive rapid detection technique up to ~1 fM concentration along with few minutes sensing. These biosensors can be manufactured on a mass-scale (billions) to detect the COVID-19 viral load in nasal, saliva, urinal, and serological samples even if the infected person is asymptotic. Methods investigated here are the most advanced available platforms for biosensing optical devices resulted from the integration of state-of-the-art designs and materials. These approaches are including but not limited to integrated optical devices, plasmonic resonance and also emerging nanomaterial biosensors. The lab-on-a-chip platforms examined here are suitable not only for SARS-CoV-2 spike protein detection but also other contagious virions such as influenza, and middle east respiratory syndrome (MERS).

In LHC Run 3, the upgraded ALICE detector will record Pb-Pb collisions at a rate of 50 kHz usingcontinuous readout. The resulting stream of raw data at 3.5 TB/s has to be processed with a setof lossy and lossless compression and data reduction techniques to a storage data rate of 90 GB/swhile preserving relevant data for physics analysis. This contribution presents a custom losslessdata compression scheme based on entropy coding as the final component in the data reductionchain which has to compress the data rate from 300 GB/s to 90 GB/s. A flexible, multi-processarchitecture for the data compression scheme is proposed that seamlessly interfaces with the datareduction algorithms of earlier stages and allows to use parallel processing in order to keep therequired firm real-time guarantees of the system. The data processed inside the compressionprocess have a structure that allows the use of an rANS entropy coder with more resource efficientstatic distribution tables. Extensions to the rANS entropy coder are introduced to efficientlywork with these static distribution tables and large but sparse source alphabets consisting of upto 25 Bit per symbol. Preliminary performance results show compliance with the firm real-timerequirements while offering close-to-optimal data compression.

We have developed a software for fast calculation of capacitances in planar silicon pixel and strip sensors, based on 3D and 2D numerical solutions of the Laplace's equation. The validity of the 2D calculations was checked with capacitances measurements on Multi-Geometry Silicon Strip Detectors (MSSD). The 3D calculations were tested by comparison with pixel sensors capacitance measurements from literature. In both cases the Laplace equation results were compared with simulations obtained from the TCAD Sentaurus suite. The developed software is a useful tool for fast estimation of interstrip, interpixel and backplane capacitances, saving computation time, as a first approximation before using a more sophisticated platform for more accurate results if needed.

A transimpedance amplifier has been designed for scanning tunneling microscopy (STM). The amplifier features low noise (limited by the Johnson noise of the 1 G{\Omega} feedback resistor at low input current and low frequencies), sufficient bandwidth for most STM applications (50 kHz at 35 pF input capacitance), a large dynamic range (0.1 pA--50 nA without range switching), and a low input voltage offset. The amplifier is also suited for placing its first stage into the cryostat of a low-temperature STM, minimizing the input capacitance and reducing the Johnson noise of the feedback resistor. The amplifier may also find applications for specimen current imaging and electron-beam-induced current measurements in scanning electron microscopy and as a photodiode amplifier with a large dynamic range. This paper also discusses the sources of noise including the often neglected effect of non-balanced input impedance of operational amplifiers and describes how to accurately measure and adjust the frequency response of low-current transimpedance amplifiers.

We present the hardware of a cheap multi-sensor magnetometric setup where a relatively large set of magnetic field components is measured in several positions by calibrated magnetoresistive detectors. The setup is developed with the scope of mapping the (inhomogeneous) field generated by a known magnetic source, which is measured as superimposed to the (homogeneous) geomagnetic field. The final goal is to use the data produced by this hardware to reconstruct position and orientation of the magnetic source with respect to the sensor frame, simultaneously with the orientation of the frame with respect to the environmental field. Possible applications of the setup are shortly discussed, together with a synthetic description of the data elaboration and analysis.

With the development of the circular collider, it is necessary to make accurate physics experimental measurements of particle properties at higher luminosity Z pole. Micro-pattern gaseous detectors (MPGDs), which contain Gaseous Electron Multiplier (GEM) and Micro-mesh gaseous structures (Micromegas), have excellent potential for development as the readout devices of the time projection chamber (TPC) tracker detector. To meet the updated physics requirements of the high luminosity Z from the preliminary concept design report (preCDR) to concept design report (CDR) at the circular electron positron collider (CEPC), In this paper, the space charge distortion of the TPC detector is simulated with the CEPC beam structure. Using the multi-physics simulation software package, the distribution of ion estimated by Geant4 is used as the input for the differential equation, and the relationship between the ion density distribution and electric field in the detector chamber is simulated. These simulation results show that the maximum deviation for Higgs O (25 μ m) meets the performance requirements in CEPC TPC detector at the high luminosity Z pole, while it is still a considerable challenge for Z pole, with the maximum deviation O ( >100 μ m). According to the previous developments, the cascaded structure of GEM and Micromegas detector has been measured. The new considerations of the detector's requirements were given, the gain needs to be reached to about 2000 with IBF ? Gain under 0.1, and IBF means the ions back flow ratio of the detector. The pixel TPC is a potential option to replace the traditional MPGDs with the low gain, low occupancy, and outstanding pattern recognition. Finally, some update parameters and experiments results were compared.

The presence of a weak remanence in Ultra-Low-Field (ULF) NMR sample containers is investigated on the basis of proton precession. The high-sensitivity magnetometer used for the NMR detection, enables simultaneously the measurement of the static field produced in the sample proximity by ferromagnetic contaminants. The presence of the latter is studied by high resolution chemical analyses of the surface, based on X-ray fluorescence spectroscopy and secondary ions mass spectroscopy. Methodologies to reduce the contamination are explored and characterized. This study is of relevance in any ULF-NMR experiment, as in the ULF regime spurious ferromagnetism becomes easily a dominant cause of artefacts.