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To version 6.1
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on 2024/01/29 11:39
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1 -= **What is iDAS?** =
1 +=== **Silixa iDAS Setup Manual for Reoccupying/Duplicating Experiment** ===
2 2  
3 -**iDAS** stands for **Integrated Distributed Acoustic Sensing**. This advanced system utilizes the principle of Rayleigh backscattering in optical fibers to measure strain rates along the fiber's length. It's a cutting-edge technology predominantly used in fields like geophysics, where it's crucial for monitoring seismic activities, as well as in industrial applications like pipeline monitoring and security systems.
4 -
5 -=== **Safety first!**
6 - ===
7 -
8 -(% class="box warningmessage" %)
9 -The iDAS uses a Class 1 laser, which is generally considered safe for most applications. However, direct exposure to the eye should be avoided to prevent any risk of eye injury.
10 -\\Cables and fibers may create tripping hazards. Ensure that the routing of cables is done in a way that minimizes the risk of accidents.
11 -
12 12  ----
13 13  
14 -=== **System Components** ===
5 +==== **General Information** ====
15 15  
16 -**Interrogator Unit**
17 -
18 -* The heart of the iDAS system, this unit contains the laser source, a detector for capturing backscattered light, and electronics to process this signal. It's critical for generating and interpreting the data collected by the optical fiber.
19 -
20 -**Optical Fiber**
21 -
22 -* This component acts as a long, distributed sensor. Strain rates along this fiber are what the iDAS system measures and analyzes.
23 -
24 -**Data Acquisition Software**
25 -
26 -* This software interfaces with the interrogator unit, allowing users to configure acquisition parameters, initiate data capture, and process the collected data.
27 -
28 -= =
29 -
30 -= =
31 -
32 -= **DAS Data Collection System** =
33 -
34 -==== **1. Interrogator Unit** ====
35 -
36 -* **Function:** The interrogator unit is the core component of a DAS system. It sends laser pulses through the optical fiber and measures the backscattered light.
37 -* **Recording Information:** It records various settings such as the optical system configurations, spatial sampling rates, and the duration of data acquisition.
38 -* **Multiple Interrogators:** More than one interrogator may be used in an experiment. Each unit should have a unique identifier and is described in its respective metadata block.
39 -
40 -==== **2. Surface Installation** ====
41 -
42 -* **Cable Arrangement:** The optical fiber cable can be a single long continuous cable or multiple cables with connectors, used across different installation environments.
43 -* **Cable Types:** Cables may vary in construction types based on the installation environment.
44 -* **Geographical Metadata:** Parameters related to geographical location are specified for easy searchability in databases.
45 -
46 -==== **3. Fiber Optic Cable** ====
47 -
48 -* **Cable Composition:** Several optical fibers may be enclosed within one cable.
49 -* **Metadata Identification:** The metadata identifies each individual fiber used in the acquisition, including its intrinsic properties.
50 -
51 -==== **4. Installation Environments** ====
52 -
53 -* **Shallow Burial:** The cable can be shallowly buried.
54 -* **In-Conduit Installation:** The cable can also be installed within a conduit.
55 -* **Water Installation:** Suitable for underwater environments.
56 -
57 -==== **5. Channels** ====
58 -
59 -* **Sensor Distribution:** Channels represent sensors distributed along the fiber array at fixed intervals.
60 -* **Physical Location Determination:** The physical locations of these channels are ascertainable through methods like tap tests and GPS tracking.
61 -* **Metadata for Channels:** Each channel or group of channels has its own metadata block, detailing specifics like location and properties.
62 -
63 -
64 -[[image:1706489800616-982.png]]
65 -
66 -
67 -
68 -[[image:1706488566274-805.png]]
69 -
70 -----
71 -
72 -= **DAS Metadata Schema** =
73 -
74 -==== **1. Interrogator** ====
75 -
76 -* **Required:** Interrogator ID, manufacturer, model.
77 -* **Optional:** Serial number, firmware version.
78 -
79 -==== **2. Acquisition Parameters** ====
80 -
81 -* **Required:** Interrogator ID, acquisition ID, unit of measure, acquisition start and end time, acquisition sample rate, gauge length, number of channels, spatial sampling interval.
82 -* **Optional:** Pulse rate, pulse width.
83 -
84 -==== **3. Overview** ====
85 -
86 -* **Required:** Network code, location, start date, end date, point of contact.
87 -* **Optional:** Digital Object Identifier (DOI), purpose of data collection, funding agency.
88 -
89 -==== **4. Cable Information** ====
90 -
91 -* **Required:** Cable ID, cable bounding box.
92 -* **Optional:** Cable owner, cable installation date, cable characteristics.
93 -
94 -==== **5. Fiber Information ('Native format')** ====
95 -
96 -* **Required:** Cable ID, fiber ID, fiber geometry, fiber mode, fiber refraction index.
97 -* **Optional:** Fiber optical length, fiber start and end location, fiber one-way attenuation, fiber winding angle.
98 -
99 -==== **6. Channel Group** ====
100 -
101 -* **Required:** Interrogator ID, acquisition ID, channel group ID, cable ID, fiber ID, coordinate generation date.
102 -* **Optional:** Location method, coordinate reference frame, first/last usable channel ID, uncertainty of various coordinates (x, y, latitude, longitude, elevation, depth, strike, dip).
103 -
104 -==== **7. Channel** ====
105 -
106 -* **Required:** Channel group ID, channel ID, coordinates (x, y, latitude, longitude).
107 -* **Optional:** Elevation above sea level, depth below surface, distance along fiber, strike, dip.
108 -
109 -----
110 -
111 -=== ===
112 -
113 -= **Pre-processing Steps for DAS Data (2.5 months, 90 TB)** =
114 -
115 -1. (((
116 -**Create a Deployment Log**
117 -
118 -* Document key details like photonics settings, duration of data collection, instances of hard disk failure, power outages, etc.
119 -)))
120 -1. (((
121 -**Generate Geographic Coordinates**
122 -
123 -* Assign latitude and longitude coordinates to each DAS channel for spatial referencing.
124 -)))
125 -1. (((
126 -**Data Conversion**
127 -
128 -* Convert the raw DAS time series data from counts to strain rate, which is more meaningful for seismic analysis.
129 -)))
130 -1. (((
131 -**Data Decimation**
132 -
133 -* Reduce the sampling rate from 1000 Hz to 100 Hz. This step is essential to manage data volume and focus on frequencies of interest for seismic activities.
134 -)))
135 -1. (((
136 -**Extract Specific Time Series**
137 -
138 -* Isolate time series data of special interest, such as those related to earthquake events, for detailed analysis.
139 -)))
140 -1. (((
141 -**Data Hosting**
142 -
143 -* Store the processed data on Research School of Earth Sciences (RSES) clusters and the National Computational Infrastructure (NCI) for accessibility and further analysis.
144 -)))
145 -1. (((
146 -**Extract Data and Instrument Response from Seismic Nodes**
147 -
148 -* Retrieve both the raw data and the corresponding instrument response characteristics for accurate interpretation of the seismic signals.
149 -)))
150 -1. (((
151 -**Long-term Archiving and Data Sharing**
152 -
153 -* Ensure that the data is archived in a format and location that supports long-term preservation and accessibility, such as the AuScope Distributed Acoustic Sensing (DAS) Collection.
154 -)))
155 -1. (((
156 -**Data Access and Record Keeping**
157 -
158 -* Maintain records and access paths (e.g., NCI local file path) for the data, including metadata and other associated records, to facilitate future research and data sharing.
159 -)))
160 -
161 -=== ===
162 -
163 -=== ===
164 -
165 -=== ===
166 -
167 -=== ===
168 -
169 -=== ===
170 -
171 -----
172 -
173 -= **Silixa iDAS Setup Manual for Reoccupying/Duplicating Experiment** =
174 -
175 -= **General Information** =
176 -
177 177  * **Experiment Name:** ~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~__
178 178  * **Local Date:** ~_~_~_~_/~_~__**/202**
179 179  * **Local Time:** ~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~__
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152 +[[image:https://photos.fife.usercontent.google.com/pw/ABLVV87kSOUibG3z-j2KEZVZsK3whKaKTz3HMBd9NH_QQycwFx_2vZ7-koa-0g=w4000-h2252-s-no-gm?authuser=0]]
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329 -[[Caption>>image:1706488806394-168.png]]
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332 332  [[image:https://photos.fife.usercontent.google.com/pw/ABLVV86phmYsze0lp1yzL-gs6stE23rmgKbOxcpCRhFmK9s25zf5UHBkgbFcOg=w1440-h2556-s-no-gm?authuser=0]]
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335 335  
336 -[[How to clean the optical connector>>image:1706488909085-143.png||alt="How to clean the optical connector"]]
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