1,338 research outputs found
Wideband digital phase comparator for high current shunts
A wideband phase comparator for precise measurements of phase difference of
high current shunts has been developed at INRIM. The two-input digital phase
detector is realized with a precision wideband digitizer connected through a
pair of symmetric active guarded transformers to the outputs of the shunts
under comparison. Data are first acquired asynchronously, and then transferred
from on-board memory to host memory. Because of the large amount of data
collected the filtering process and the analysis algorithms are performed
outside the acquisition routine. Most of the systematic errors can be
compensated by a proper inversion procedure.
The system is suitable for comparing shunts in a wide range of currents, from
several hundred of milliampere up to 100 A, and frequencies ranging between 500
Hz and 100 kHz. Expanded uncertainty (k=2) less than 0.05 mrad, for frequency
up to 100 kHz, is obtained in the measurement of the phase difference of a
group of 10 A shunts, provided by some European NMIs, using a digitizer with
sampling frequency up to 1 MHz. An enhanced version of the phase comparator
employs a new digital phase detector with higher sampling frequency and
vertical resolution. This permits to decrease the contribution to the
uncertainty budget of the phase detector of a factor two from 20 kHz to 100
kHz. Theories and experiments show that the phase difference between two high
precision wideband digitizers, coupled as phase detector, depends on multiple
factors derived from both analog and digital imprint of each sampling system.Comment: 20 pages, 9 figure
Asynchronous Phase Comparator for Characterization of Devices for PMUs Calibrator
This paper reports recent progress in developing a new asynchronous digital phase comparator for the precision measurement of phase difference of voltage ratio devices and calibration of functional elements of phasor measurement units (PMUs) calibrator. The phase error of the proposed digital comparator is below 300 nrad at 50 Hz and 100 μrad at 100 kHz with applied voltages ranging between 500 mV and 3 V, whereas the phase error of cables and connectors was estimated to be 4 μrad at 1 MHz. Besides resistive dividers, the phase comparator has been employed for the characterization of frequency behavior of phase difference between the output and input of voltage and transconductance amplifiers for a PMUs calibrator. The system can also be an important tool for phase-frequency characterization of devices employed for specific wideband power measurements
Development of the Beam Position Monitors for the Diagnostics of the Test Beam Line in the CTF3 at CERN
The work for this thesis is in line with the field of Instrumentation for Particle Accelerators,
so called Beam Diagnostics. It is presented the development of a series of
electro-mechanical devices called Inductive Pick-Ups (IPU) for Beam Position Monitoring
(BPM). A full set of 17 BPM units (16 + 1 spare), named BPS units, were built and
installed into the Test Beam Line (TBL), an electron beam decelerator, of the 3rd CLIC
Test Facility (CTF3) at CERN ¿European Organization for the Nuclear Research¿.
The CTF3, built at CERN by an international collaboration, was meant to demonstrate
the technical feasibility of the key concepts for CLIC ¿Compact Linear Collider¿ as a
future linear collider based on the novel two-beam acceleration scheme, and in order to
achieve the next energy frontier for a lepton collider in theMulti-TeV scale. Modern particle
accelerators and in particular future colliders like CLIC requires an extreme alignment
and stabilization of the beam in order to enhance its quality, which rely heavily on a beam
based alignment techniques. Here the BPMs, like the BPS-IPU, play an important role
providing the beam position with precision and high resolution, besides a beam current
measurement in the case of the BPS, along the beam lines.
The BPS project carried out at IFIC was mainly developed in two phases: prototyping
and series production and test for the TBL.
In the first project phase two fully functional BPS prototypes were constructed, focusing
in this thesis work on the electronic design of the BPS on-board PCBs (Printed Circuit
Boards) which are based on transformers for the current sensing and beam position measurement.
Furthermore, it is described the monitor mechanical design with emphasis on
all the parts directly involved in its electromagnetic functioning, as a result of the coupling
of the EM fields generated by the beam with those parts. For that, it was studied
its operational parameters, according the TBL specifications, and it was also simulated a
new circuital model reproducing the BPS monitor frequency response for its operational
bandwidth (1kHz-100MHz). These prototypes were initially tested in the laboratories of
the BI-PI section¿Beam Instrumentation - Position and Intensity¿ at CERN.
In the second project phase the BPS monitor series, which were built based on the experience
acquired during the prototyping phase, the work was focused on the realization of
the characterization tests to measure the main operational parameters of each series monitor,
for which it was designed and constructed two test benches with different purposes
and frequency regions. The first one is designed to work in the low frequency region,
between 1kHz-100MHz, in the time scale of the electron beam pulse with a repetition
period of 1s and an approximate duration of 140ns. This kind of test setups called Wire
Test-bench are commonly used in the accelerators instrumentation field in order to determine
the characteristic parameters of a BPM (or pick-up) like its linearity and precision
in the position measurement, and also its frequency response (bandwidth). This is done
by emulating a low current intensity beam with a stretched wire carrying a current signals which can be precisely positioned with respect the device under test. This test bench was
specifically made for the BPS monitor and conceived to perform the measurement data
acquisition in an automated way, managing the measurement equipment and the wire positioning
motors controller from a PC workstation. Each one of the BPS monitors series
were characterized by using this system at the IFIC labs, and the test results and analysis
are presented in this work.
On the other hand, the high frequency tests, above the X band in the microwave spectrum
and at the time scale of the micro-bunch pulses with a bunching period of 83ps
(12GHz) inside a long 140ns pulse, were performed in order to measure the longitudinal
impedance of the BPS monitor. This must be low enough in order to minimize the
perturbations on the beam produced at crossing the monitor, which affects to its stability
during the propagation along the line. For that, it was built the high frequency test bench
as a coaxial waveguide structure of 24mm diameter matched at 50¿ and with a bandwidth
from 18MHz to 30GHz, which was previously simulated, and having room in the
middle to place the BPS as the device under test. This high frequency test bench is able
to reproduce the TEM (Transversal Electro-Magnetic) propagative modes corresponding
to an ultra-relativistic electron beam of 12GHz bunching frequency, so that the Scattering
parameters can be measured to obtain the longitudinal impedance of the BPS in the
frequency range of interest.
Finally, it is also presented the results of the beam test made in the TBL line, with
beam currents from 3.5A to 13A (max. available at the moment of the test). In order
to determine the minimum resolution attainable by a BPS monitor in the measurement
of the beam position, being the device figure of merit, with a resolution goal of 5¿m at
maximum beam current of 28A according to the TBL specifications.García Garrigós, JJ. (2013). Development of the Beam Position Monitors for the Diagnostics of the Test Beam Line in the CTF3 at CERN [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/34327TESI
EMN-Q - Strategic Research Agenda and Quantum Technologies Roadmaps
Together with the EMN-Q web platform, EMN-Q events and workshops this Strategic Research Agendanrepresents, in the intention of the EMN-Q members, one of the main communication channels to QT stakeholders from academia, industry, and standardisation bodies.
The Strategic Research Agenda once developed will be periodically updated by the EMN-Q, with the
support of the QT community, to ensure that QT metrology needs, even if evolving, are taken into
account and national metrology activities are coordinated, prioritised and focussed. The roadmaps will ensure that NMIs can align their research programmes in anticipation of future needs so that European QTs will be supported far into the future. In turn, QT stakeholders will acquire confidence that their metrological needs will be addressed by a long-term and coherent approach; improving on the present situation where short-term projects are based on ad-hoc needs. NMIs' awareness and involvement early on in device development will provide assurances to the user community and help the QT market to grow
Real-time virtual metrology and control for plasma etch
Plasma etch is a semiconductor manufacturing process during which material is removed from the surface
of semiconducting wafers, typically made of silicon, using gases in plasma form. A host of chemical
and electrical complexities make the etch process notoriously difficult to model and troublesome to
control. This work demonstrates the use of a real-time model predictive control scheme to control plasma
electron density and plasma etch rate in the presence of disturbances to the ground path of the chamber.
Virtual metrology (VM) models, using plasma impedance measurements, are used to estimate the plasma
electron density and plasma etch rate in real time for control, eliminating the requirement for invasive
measurements. The virtual metrology and control schemes exhibit fast set-point tracking and disturbance
rejection capabilities. Etch rate can be controlled to within 1% of the desired value. Such control represents
a significant improvement over open-loop operation of etch tools, where variances in etch rate of up to
5% can be observed during production processes due to disturbances in tool state and material properties
From analog to digital
Analog-to-digital conversion and its reverse, digital-to-analog conversion, are ubiquitous in all modern electronics, from instrumentation and telecommunication equipment to computers and entertainment. We shall explore the consequences of converting signals between the analog and digital domains and give an overview of the internal architecture and operation of a number of converter types. The importance of analog input and clock signal integrity will be explained and methods to prevent or mitigate the effects of interference will be shown. Examples will be drawn from several manufacturers' datasheets
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