Design and development of a reduced form-factor high accuracy three-axis teslameter

Acknowledgments: The authors would like to thank Reuben Debono for his useful guidance and help in the PCB assembly of the instruments at the Electronic Systems Lab at the Faculty of Engineering at University of Malta. The authors would like to thank R. Ganter, project leader of the Athos undulator beamline and H-H. Braun, SwissFEL machine director, for their constant support throughout the entire project. The authors would like to thank Sasa Spasic and his team at Sentronis facilities for their fruitful discussions and their guidance during testing.A novel three-axis teslameter and other similar machines have been designed and developed for SwissFEL at the Paul Scherrer Institute (PSI). The developed instrument will be used for high fidelity characterisation and optimisation of the undulators for the ATHOS soft X-ray beamline. The teslameter incorporates analogue signal conditioning for the three-axes interface to a SENIS Hall probe, an interface to a Heidenhain linear absolute encoder and an on-board high-resolution 24-bit analogue-to-digital conversion. This is in contrast to the old instrumentation setup used, which only comprises the analogue circuitry with digitization being done externally to the instrument. The new instrument fits in a volumetric space of 150 mm × 50 mm × 45 mm, being very compact in size and also compatible with the in-vacuum undulators. This paper describes the design and the development of the different components of the teslameter. Performance results are presented that demonstrate offset fluctuation and drift (0.1–10 Hz) with a standard deviation of 0.78 µT and a broadband noise (10–500 Hz) of 2.05 µT with an acquisition frequency of 2 kHz.peer-reviewe

Calibration and characterization of a reduced form-factor high accuracy three-axis teslameter

A new reduced form-factor three axes digital teslameter, based on the spinning current technique, has been developed. This instrument will be used to characterize the SwissFEL insertion devices at the Paul Scherrer Institute (PSI) for the ATHOS soft X-ray beamline. A detailed and standardized calibration procedure is critical to optimize the performance of this precision instrument. This paper presents the measurement techniques used for the corrective improvements implemented through non-linearity, temperature offset, temperature sensitivity compensation of the Hall probe and electronics temperature compensation. A detailed quantitative analysis of the reduction in errors on the application of each step of the calibration is presented. The percentage peak error reduction attained through calibration of the instrument for reference fields in the range of ±2 T is registered to drop from 1.94% down to 0.02%.peer-reviewe

The Enzyme Immobilization: Carriers and immobilization methods

Strategies based on the enzyme application are increasingly replacing the conventional chemical procedures because of their efficiency, quicker performance and environmental protection. However, natural enzymes can rarely be used in industry since their beneficial features can not endure the industrial conditions. Additional drawbacks of natural enzymes are their inhibition by reaction products and difficulty to be removed from the reaction mixture. The most promising technique to substantially improve the enzyme properties, such as activity, pH, thermal and organic-solvent stability, reusability and storage stability, in non-natural environments is by the enzyme immobilization. In this review we summarized different techniques used to immobilize enzymes to inert carriers. A wide variety of materials of both the organic and inorganic origin was used as carriers for the enzyme immobilization. We also summarized a class of new materials where the enzyme performance was enhanced by combining different classical materials and shaping in specific forms

CMOS imager based on single photon avalanche diodes

In this paper we report on a 32×32 optical imager based on single photon avalanche diodes integrated in CMOS technology. The maximum measured dynamic range is 120dB and the minimum noise equivalent intensity is 1.3×-3lx. The minimum integration time per pixel is 4μs. The output of each pixel is digital, thereby requiring no complex read-out circuitry, no amplification, no sample & hold, and no ADC

Semiconductor device for measuring ultra small electrical currents and small voltages

A semiconductor device for measuring ultra low currents down to the level of single electrons or low voltages comprises a first and a second voltage supply terminal (1, 2), an input terminal (3) for receiving an electrical current or being supplied with a voltage to be measured, a bipolar transistor (5) having a base (B), an emitter (E) and a collector (C), wherein a first PN junction is formed between the base and the collector and a second PN junction is formed between the base and the emitter, wherein the emitter is coupled to the input terminal and the base is coupled to the second voltage supply terminal, and wherein the first PN junction is designed for reverse biased operation as an avalanche diode, and a quenching and recharging circuit (6) having a first terminal (7) coupled to the first voltage supply terminal and a second terminal (8) coupled to the collector (C) of the bipolar transistor (5), the quenching and recharging circuit permitting operation of the first PN junction reverse biased above the breakdown voltage of the first PN junction

Magnetic field sensor measuring a direction of a magnetic field in a plane and current sensor

A magnetic field sensor for measuring a direction of a magnetic field in a plane comprises two sensing structures (1A 1B) that can be operated as a rotating Hall element. The two Hall elements are rotated in discrete steps in opposite directions. Such a magnetic field sensor can be used as current sensor for measuring a primary current flowing through a conductor (15)

A low-cost inductive proximity sensor for industrial applications

The paper presents an inductive proximity sensor with fully integrated electronics. The sensor with the compact hybrid configuration is composed of a sensing flat coil and an integrated electronic interface. The sensor exhibits a longitudinal resolution of 120 nm for an aluminum target position up to 500 µm from the sensing coil. The total working range is from 100 µm to 1200 µm. The temperature drift of the sensor is less than 400 ppm/°C. The sensor power consumption is 125 mW and the active sensor dimensions are 1.5mm x 1.5mm x 1.2mm

Semiconductor photodiode and method of making

A semiconductor photodiode (18) is formed as a pn-junction between a region (2) of a first conductivity type and a region (6) of a second conductivity type. The region (6) of the second conductivity type is approximately hemispherical. A mini guard ring (8), i.e. a ring of the second conductivity type having a junction depth that is much smaller than the junction depth of the region (6) preferably surrounds the region (6) in order to prevent surface trapping. The photodiode (18) is operated with a high reverse bias so that light falling on the photodiode (18) produces the avalanche effect

Current and voltage ADC using a differential pair of single-electron bipolar avalanche transistors

Single-electron bipolar avalanche transistors (SEBATs) enable current sensing by electron counting at room temperature. Here, differential SEBAT circuits combining the functions of amplification and analog-to-digital (A/D) conversion are proposed and characterized for two applications: Low-current AID conversion and differential voltage A/D conversion. Charge detection efficiencies in the order of 30% are reached, allowing for the direct A/D conversion of currents in the 10(-13) A range. An equivalent of the differential pair is used as a differential voltage ADC

The pronoun sto and its semantic and syntactic derivatives in the vernacular of the Sirinic county

This paper analyzes the pronoun što and its semantic and syntactic derivatives in the Prizren - South Morava dialect in the Sirinić county (Sirinićka Župa), in the northern part of the Šar Mountains. The paper focuses primarily on the syntactic use of što, while its semantic derivatives are outlined mainly in terms of references to the previous research on the subject. The dialect corpus shows that this lexeme has a wide range of syntactic realizations - it can be used as a relativizer in defining and non-defining relative clauses, as a conjunction in the clauses of reason and declarative clauses, and it can also be used as a pronoun and adverb. Moreover, the research includes the cases in which što was found to be a part of multi-word conjunctions in hypotactic or paratactic structures. This paper primarily aims to determine and examine the syntactic positions in which što is realized and the environment in which it is used. In the majority of the observed cases, there were also other corresponding syntactic devices, so that the focus was also placed on determining the frequency of the lexeme što in these positions in relation to its synonymous syntactic counterparts. The fact that the form što is widely used in the Sirinić vernacular as a conjunction in relative clauses points to its provenance in a wider Serbian-Macedonian area as well as to its not being included in the standard Serbian language, in lieu of which the form koji is predominantly used. In the vernacular of Sirinić county, the lexeme što is used as a conjunction in declarative object clauses, and it is also the principal conjunction in the clauses of reason.Publishe