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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 -= **DAS Data Collection System** =
5 +==== **General Information** ====
15 15  
16 -==== **1. Interrogator Unit** ====
17 -
18 -* **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.
19 -* **Recording Information:** It records various settings such as the optical system configurations, spatial sampling rates, and the duration of data acquisition.
20 -* **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.
21 -
22 -==== **2. Surface Installation** ====
23 -
24 -* **Cable Arrangement:** The optical fiber cable can be a single long continuous cable or multiple cables with connectors, used across different installation environments.
25 -* **Cable Types:** Cables may vary in construction types based on the installation environment.
26 -* **Geographical Metadata:** Parameters related to geographical location are specified for easy searchability in databases.
27 -
28 -==== **3. Fiber Optic Cable** ====
29 -
30 -* **Cable Composition:** Several optical fibers may be enclosed within one cable.
31 -* **Metadata Identification:** The metadata identifies each individual fiber used in the acquisition, including its intrinsic properties.
32 -
33 -==== **4. Installation Environments** ====
34 -
35 -* **Shallow Burial:** The cable can be shallowly buried.
36 -* **In-Conduit Installation:** The cable can also be installed within a conduit.
37 -* **Water Installation:** Suitable for underwater environments.
38 -
39 -==== **5. Channels** ====
40 -
41 -* **Sensor Distribution:** Channels represent sensors distributed along the fiber array at fixed intervals.
42 -* **Physical Location Determination:** The physical locations of these channels are ascertainable through methods like tap tests and GPS tracking.
43 -* **Metadata for Channels:** Each channel or group of channels has its own metadata block, detailing specifics like location and properties.
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46 -[[image:1706489800616-982.png]]
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50 -[[image:1706488566274-805.png]]
51 -
52 -----
53 -
54 -= **DAS Metadata Schema** =
55 -
56 -==== **1. Interrogator** ====
57 -
58 -* **Required:** Interrogator ID, manufacturer, model.
59 -* **Optional:** Serial number, firmware version.
60 -
61 -==== **2. Acquisition Parameters** ====
62 -
63 -* **Required:** Interrogator ID, acquisition ID, unit of measure, acquisition start and end time, acquisition sample rate, gauge length, number of channels, spatial sampling interval.
64 -* **Optional:** Pulse rate, pulse width.
65 -
66 -==== **3. Overview** ====
67 -
68 -* **Required:** Network code, location, start date, end date, point of contact.
69 -* **Optional:** Digital Object Identifier (DOI), purpose of data collection, funding agency.
70 -
71 -==== **4. Cable Information** ====
72 -
73 -* **Required:** Cable ID, cable bounding box.
74 -* **Optional:** Cable owner, cable installation date, cable characteristics.
75 -
76 -==== **5. Fiber Information ('Native format')** ====
77 -
78 -* **Required:** Cable ID, fiber ID, fiber geometry, fiber mode, fiber refraction index.
79 -* **Optional:** Fiber optical length, fiber start and end location, fiber one-way attenuation, fiber winding angle.
80 -
81 -==== **6. Channel Group** ====
82 -
83 -* **Required:** Interrogator ID, acquisition ID, channel group ID, cable ID, fiber ID, coordinate generation date.
84 -* **Optional:** Location method, coordinate reference frame, first/last usable channel ID, uncertainty of various coordinates (x, y, latitude, longitude, elevation, depth, strike, dip).
85 -
86 -==== **7. Channel** ====
87 -
88 -* **Required:** Channel group ID, channel ID, coordinates (x, y, latitude, longitude).
89 -* **Optional:** Elevation above sea level, depth below surface, distance along fiber, strike, dip.
90 -
91 -----
92 -
93 -=== ===
94 -
95 -= **Pre-processing Steps for DAS Data (2.5 months, 90 TB)** =
96 -
97 -1. (((
98 -**Create a Deployment Log**
99 -
100 -* Document key details like photonics settings, duration of data collection, instances of hard disk failure, power outages, etc.
101 -)))
102 -1. (((
103 -**Generate Geographic Coordinates**
104 -
105 -* Assign latitude and longitude coordinates to each DAS channel for spatial referencing.
106 -)))
107 -1. (((
108 -**Data Conversion**
109 -
110 -* Convert the raw DAS time series data from counts to strain rate, which is more meaningful for seismic analysis.
111 -)))
112 -1. (((
113 -**Data Decimation**
114 -
115 -* 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.
116 -)))
117 -1. (((
118 -**Extract Specific Time Series**
119 -
120 -* Isolate time series data of special interest, such as those related to earthquake events, for detailed analysis.
121 -)))
122 -1. (((
123 -**Data Hosting**
124 -
125 -* Store the processed data on Research School of Earth Sciences (RSES) clusters and the National Computational Infrastructure (NCI) for accessibility and further analysis.
126 -)))
127 -1. (((
128 -**Extract Data and Instrument Response from Seismic Nodes**
129 -
130 -* Retrieve both the raw data and the corresponding instrument response characteristics for accurate interpretation of the seismic signals.
131 -)))
132 -1. (((
133 -**Long-term Archiving and Data Sharing**
134 -
135 -* 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.
136 -)))
137 -1. (((
138 -**Data Access and Record Keeping**
139 -
140 -* 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.
141 -)))
142 -
143 -=== ===
144 -
145 -=== ===
146 -
147 -=== ===
148 -
149 -=== ===
150 -
151 -=== ===
152 -
153 -----
154 -
155 -= **Silixa iDAS Setup Manual for Reoccupying/Duplicating Experiment** =
156 -
157 -= **General Information** =
158 -
159 159  * **Experiment Name:** ~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~__
160 160  * **Local Date:** ~_~_~_~_/~_~__**/202**
161 161  * **Local Time:** ~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~__
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297 297  * Regularly check the condition of all cables and connectors.
298 298  * Before leaving the setup, confirm that data saving is active if required.
299 299  * Keep a log of all actions taken during the setup for future reference and troubleshooting.
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314 -[[image:https://photos.fife.usercontent.google.com/pw/ABLVV86phmYsze0lp1yzL-gs6stE23rmgKbOxcpCRhFmK9s25zf5UHBkgbFcOg=w1440-h2556-s-no-gm?authuser=0]]
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318 -[[How to clean the optical connector>>image:1706488909085-143.png||alt="How to clean the optical connector"]]
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