Commit 37cad8c9 authored by Chiara Di Fronzo's avatar Chiara Di Fronzo

updates

parent ead0d192
\chapter{Assembling suspension chains for A+ at LHO} \chapter{Assembling suspension chains for A+ at LHO}
\label{A} \label{A}
\ No newline at end of file In 2019 I spent some months working on LIGO Hanford site. Along with the study exposed in Chapter 5, I offered my lab experience in building the HSTS suspensions to be installed for the A+ upgrade. The assembly team was composed by me, Dr. Rahul Kumar and Dr. Jeff Bartlett. The suspensions have been installed in 2021 under the supervision of Rahul. Here there is a gallery of original photos of the lab work done together. It was an intense and very interesting team work, which enhanced my skills in working into a clean room, with delicate structures that needed to be assembled very precisely.
\begin{figure}
\centering
\includegraphics[scale=1]{images/blades.jpg} \includegraphics[scale=0.8]{images/blades2.jpg}
\caption[Mounting the blades]{Mounting the blades onto the top of the suspension skeleton. On the right photo: the blades mounted and fixed and the required angle.}
\end{figure}
\begin{figure}
\centering
\includegraphics[scale=0.7]{images/wire.jpg} \includegraphics[scale=0.6]{images/tension.jpg}
\caption[Preparing the suspending wires]{Left: one of the wire used to suspend the test mass. Right: Technique to prepare the wire with the right tension: a given weight is applied and left for 5 minutes.}
\end{figure}
\begin{figure}
\centering
\includegraphics[scale=1]{images/support.jpg} \includegraphics[scale=1]{images/wiresupinstall.jpg}
\caption[Mounting the wires and their support]Mounting the wires for the test mass suspension on their support. Right: Jeff and I while installing the wire support into the suspension cage.}
\end{figure}
\begin{figure}
\centering
\includegraphics[scale=2.2]{images/TMinstall.jpg}\\
\includegraphics[scale=2.2]{images/Rahul.jpg}
\caption[Installing the test masses]{Top: Rahul and I installing the bottom test mass and suspending it with the wires. Bottom: Rahul while measuring the alignment of the test mass into the suspension cage.}
\end{figure}
\chapter{The low frequency window} \chapter{The low frequency window}
\label{LF} \label{LF}
The scientific research exposed in this thesis focusses on the improvement of ground-based gravitational-wave detectors at low frequency. This chapter intends to frame the work done in this context and highlight why the lower frequency window is so important. The discussion around this topic is relatively recent and it has been widely discussed during dedicated workshops which the author of this thesis attended since 2018. The scientific research exposed in this thesis focusses on the improvement of ground-based gravitational-wave detectors at low frequency. This chapter intends to frame the work done in this context and highlight why the lower frequency window is so important. The discussion around this topic is relatively recent and it has been widely debated during dedicated workshops which the author of this thesis attended since 2018.
\subsection{Sources of gravitational waves} \subsection{Sources of gravitational waves}
Fig. \ref{spec} summarizes the possible objects that can be gravitational waves sources, their frequency emission and what kind of instrument can detect them. The terrestrial interferometric detectors are the most involved at present times, but the efforts of the scientific community are going towards the development of new detectors both ground- and space-based in order to widen the frequency window of observation. Fig. \ref{spec} summarizes the possible objects that can be gravitational waves sources, their frequency emission and what kind of instrument can detect them. The terrestrial interferometric detectors are the most involved at present times, but the efforts of the scientific community are going towards the development of new detectors both ground- and space-based in order to widen the frequency window of observation.
......
...@@ -16,8 +16,8 @@ ...@@ -16,8 +16,8 @@
% %
%\begin{document} %\begin{document}
\chapter{Laser stabilization for 6D isolation system device} \chapter{Laser stabilization for 6D isolation system device}
In this chapter I will introduce the 6D device, a new technology for inertial isolation. This project has been presented to the scientific community at the 10th ET Symposium in 2019 \cite{poster}. My contribution to the development of this technique focussed on the sensing side: a laser will be injected into the device and will need to be stabilized in frequency. We will see here why and how.\\ In this chapter I will introduce the 6D device, a new technology for inertial isolation. This project has been presented to the scientific community at the 10th ET Symposium in 2019 \cite{poster}. My contribution to the development of this technique focussed on the sensing side: a laser will be injected into the device and will need to be stabilized in frequency. To do it, we propose a new technique based on compact interferometry.\\
This work has been done entirely at UoB during the pandemic period: the design of the project has been conducted from home during the lockdown in 2020, while the experiment has been built and tested from September 2020, when the University accorded me the permission to return to the lab. This work has been done entirely at UoB: the design of the project has been conducted in 2020, while the experiment has been built and tested from September 2020, when the University accorded me the permission to return to the lab.
\section{6D inertial isolation system overview} \section{6D inertial isolation system overview}
The 6D inertial isolation system is a device based on a new technology under development at University of Birmingham and at Vrije Univestiteit in Amsterdam, which could enable detection of gravitational waves at 10 Hz and below \cite{6d}. We have already seen the importance for this frequency window to be opened (chap 2): this facility can be installed on Earth-based interferometers of every type, on or under ground, allowing the different instruments to easily use the same device.\\ The 6D inertial isolation system is a device based on a new technology under development at University of Birmingham and at Vrije Univestiteit in Amsterdam, which could enable detection of gravitational waves at 10 Hz and below \cite{6d}. We have already seen the importance for this frequency window to be opened (chap 2): this facility can be installed on Earth-based interferometers of every type, on or under ground, allowing the different instruments to easily use the same device.\\
...@@ -98,7 +98,7 @@ In the plot in Fig. \ref{perf} there is the analysis and comparison with two of ...@@ -98,7 +98,7 @@ In the plot in Fig. \ref{perf} there is the analysis and comparison with two of
\begin{figure}[h!] \begin{figure}[h!]
\centering \centering
\includegraphics[scale=0.3]{images/perf.png} \includegraphics[scale=0.3]{images/perf.png}
\caption{Analysis and comparison of RIO Orion laser with other products and with the configuration involving HoQIs.} \caption[Analysis and comparison of RIO Orion laser with other products]{Analysis and comparison of RIO Orion laser with other products and with the configuration involving HoQIs.}
\label{perf} \label{perf}
\end{figure} \end{figure}
\noindent \noindent
...@@ -169,7 +169,7 @@ The two HoQIs have been tuned to obtain the best fringe visibility, which is 0.8 ...@@ -169,7 +169,7 @@ The two HoQIs have been tuned to obtain the best fringe visibility, which is 0.8
\begin{figure}[h!] \begin{figure}[h!]
\centering \centering
\includegraphics[scale=0.3]{images/fringes.png} \includegraphics[scale=0.3]{images/fringes.png}
\caption[HoQI fringes alignment.]{Example of how we set the fringes of the HoQIs to obtain the desired alignment. Every photodiode detects the fringes independently from the others: to obtain the same response, we adjusted the offsets and the gains of each diode on the pre-amplifier and via software.} \caption[HoQI fringes alignment]{Example of how we set the fringes of the HoQIs to obtain the desired alignment. Every photodiode detects the fringes independently from the others: to obtain the same response, we adjusted the offsets and the gains of each diode on the pre-amplifier and via software.}
\label{fringes} \label{fringes}
\end{figure} \end{figure}
...@@ -239,7 +239,7 @@ This test shows that HoQI2 is in general noisier than HoQI1, especially above 1 ...@@ -239,7 +239,7 @@ This test shows that HoQI2 is in general noisier than HoQI1, especially above 1
\begin{figure}[h!] \begin{figure}[h!]
%\centering %\centering
\includegraphics[scale=0.3]{images/hoqisOLCL.png} \includegraphics[scale=0.3]{images/hoqisOLCL.png}
\caption[In-loop test of HoQIs performances.]{In-loop test of HoQIs performances. The out-of-loop traces (cyan and purple) are following the free running frequency noise trace (blue) as expected, while when the loop is closed the HoQI outputs (green and red) show that the controllers are pushing the expected gain (orange). There is an evident un-match with the orange trace below 0.4 Hz and this is likely due to loop leakage.} \caption[In-loop test of HoQIs performances]{In-loop test of HoQIs performances. The out-of-loop traces (cyan and purple) are following the free running frequency noise trace (blue) as expected, while when the loop is closed the HoQI outputs (green and red) show that the controllers are pushing the expected gain (orange). There is an evident un-match with the orange trace below 0.4 Hz and this is likely due to loop leakage.}
\label{looptest} \label{looptest}
\end{figure} \end{figure}
...@@ -250,7 +250,7 @@ Several tests have been taken in different conditions for noise hunting along th ...@@ -250,7 +250,7 @@ Several tests have been taken in different conditions for noise hunting along th
\begin{figure}[h!] \begin{figure}[h!]
\centering \centering
\includegraphics[scale=0.3]{images/result.png} \includegraphics[scale=0.3]{images/result.png}
\caption{Results of frequency stabilization: the in-loop red trace shows the frequency stabilization process as detected by the frequency counter monitoring the beat-note between the two lasers; the black trace is the expected gain activated by the controllers, which is set to maximise the stabilization below 1 Hz.} \caption[Results of frequency stabilization tests]{Results of frequency stabilization: the in-loop red trace shows the frequency stabilization process as detected by the frequency counter monitoring the beat-note between the two lasers; the black trace is the expected gain activated by the controllers, which is set to maximise the stabilization below 1 Hz.}
\label{test} \label{test}
\end{figure} \end{figure}
......
...@@ -84,7 +84,7 @@ HAM = Horizontal Access Module\\ ...@@ -84,7 +84,7 @@ HAM = Horizontal Access Module\\
HEPI = Hydraulic External Pre-Isolator\\ HEPI = Hydraulic External Pre-Isolator\\
HoQI = Homodyne Quadrature Interferometer\\ HoQI = Homodyne Quadrature Interferometer\\
HP = High Pass filter\\ HP = High Pass filter\\
HSTS = \\ HSTS = HAM Small Triple Suspension\\
IMC = Input Mode Cleaner\\ IMC = Input Mode Cleaner\\
IMCL = Input Mode Cleaner Length\\ IMCL = Input Mode Cleaner Length\\
ISI = Internal Seismic Isolation\\ ISI = Internal Seismic Isolation\\
...@@ -112,7 +112,7 @@ RIN = Relative Intensity Noise\\ ...@@ -112,7 +112,7 @@ RIN = Relative Intensity Noise\\
SC = Sensor Correction\\ SC = Sensor Correction\\
SR = Signal Recycling\\ SR = Signal Recycling\\
SRCL = Signal Recycling Cavity Length\\ SRCL = Signal Recycling Cavity Length\\
STS = \\ STS = Streckheisen Tri-axial Seismometer\\
TEC = Thermo-Electric Controller\\ TEC = Thermo-Electric Controller\\
UoB = University of Birmingham\\ UoB = University of Birmingham\\
...@@ -278,6 +278,7 @@ Beginning of Gravitational Wave Astronomy} ...@@ -278,6 +278,7 @@ Beginning of Gravitational Wave Astronomy}
\end{thebibliography} \end{thebibliography}
%ringraziamenti personali vanno qui %\chapter*{Grazie!}
%Personal acknowledgements
\end{document} \end{document}
\ No newline at end of file
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