TRIDENT_Deployment/KM3Net_Deployment.md

### Design and deployment of KM3Net DU

#### Geological and physical oceanography background of KM3Net sites
  <img src="./img/KM3Net_Location.png" width="800">
  
 - The KM3NeT-Italy infrastructure is located at 36° 16′ N 16° 06′ E at a depth of `3500` m, about `100 km` offshore from Porto Palo di Capo Passero, Sicily, Italy. `ARCA`
 - The KM3NeT-France infrastructure is located at 42° 48′ N 06° 02′ E at a depth of `2450` m, about `40 km` offshore from Toulon, France. `ORCA`


 #### Configuration of KM3Net-ORCA Detector
 

 <img src="./img/ORCA_detector.png" width="800">
 
- KM3Net-Fr海底中微子望远镜规划由115串潜标阵列（DU）组成
- 每一个DU包括18个玻璃球（DOM）
- 每一个DOM内嵌31个光电倍增管（PMT）
- DU展开长度为200米，DOM间隔在8~10米之间
- DU之间间隔在20~23米之间

 #### DU Configuration of KM3Net-ORCA Detector
 
  <img src="./img/KM3Net_DU_Unfold.png" width="800">
  <img src="./img/ORCA_DU_Fold.png" width="800">
  <img src="./img/ORCA_DOMs.png" width="800">  
  <img src="./img/ORCA_DU.png" width="800">
      
  The ensemble of the loaded LOM and anchor weighs approximately `26 kN`. In seawater the weight is approximately `5.5 kN`. The ensemble is lowered with a winch cable to the seafloor from a dedicated ship (figure 8). Positioning at the seafloor requires an acoustic positioning system with a transponder to the lowered ensemble. The required accuracy is about `±1 m`. Further assistance is needed from an ROV to connect the interlink to the sea-floor network, i.e. connect the VEOC backbone via the base module of the DU-string to the network to shore. After successful connection, of which the verification takes about 30 minutes, the winch cable is released acoustically. This verification entails a full test of the DU-string in furled position: powering on, and testing the communication with each optical module.
  In principle, the ensemble could be hauled up again to the surface if the DU-string does not pass the verification test. To provide more freedom to the ship’s maneuvering and wave motion during the verification, a *`small buoy is attached a few tens of meters above the LOM`* to allow for slack in the winch cable without danger of entanglement or collision of the acoustic release with the sphere. Once the release mechanism described in section 4.5 is opened by the ROV pulling the rope near the seafloor the LOM moves upwards from its support structure at the anchor-frame and starts self-unrolling along the two Dyneema ropes.

  After `10 sea-trials`, the first complete DU-string deployments were successfully launched with the complete unrolling of an ARCA DU-string up to 750 m long, the undamaged exiting of optical modules and backbone cable and the surfacing of the LOM.`Loading the LOM and deploying it to the seafloor are procedures that require training of dedicated teams. `
  
 通过以上的文献资料检索，可以判断一些KM3Net的DU（串列）的基本参数：
 
 - 空气中重量2.6吨；
 - 水中重量550kg;
 - 布放位置精度要求小于1米；

 
 
  
  
  
### Photo gallery of KM3Net DU deployment 


#### Trailer of ARCA Deployment in 2016

 <img src="./img/2016_ARCA_Deployment.gif" width="800">
 
 

#### trailer of ORCA DU deployment in 2019
  <img src="./img/Onboard_Deployment.gif" width="800">
  
Note: 
1. 水面布放时，LOM上有一个若干玻璃球组成的Hoisting frame，水下声学释放脱钩操作时，该部分和主体已经分开。和ARCA的LOM之上有一个crown的设计类似。这个组件的设计初衷和在布放过程中的作用尚不清楚，有些文字段落中表述该部分是Floatation Acoustic release frame，应该是用于回收声学释放器的。但声学释放器也可以直接连到布放缆的末端，不需要单独回收。
2. 在视频结束时，可看到水面作业形式为双船联合作业，布放船和ROV母船在平静海况下联合作业。

  <img src="./img/Acoustic_Release.gif" width="800">

该视频清晰的展示了LOM是通过声学释放的方式，从布放船的布放缆上脱开。

以上两个片段，取自2019年CNRS出品的ORCA串列的布放记录片。

#### September 2021 and June 2022 ARCA Deployment

five new detection units of KM3NeT, onboard the Handin Tide
此次ARCA的设备布放，是使用了一艘船，该船为Handin Tide，船尾有小型A架，船侧舷有Furgo ROV。
 <img src="./img/Handin_Tide_ROV.jpeg" width="800">
 
 <img src="./img/ARCA_2021_Details.png" width="800">
 
 这个信息中提到了布放流程，在LOM接近海底时，由ROV抵近进行牵引和旋转。
 
  <img src="./img/preparation_deployment_ARCA_DU_16.jpeg" width="800">
  
 注意:现在的LOM没有Crown的那个部分，也没有在起吊缆末端增加声学释放器，是起吊缆直接通过三个穿过Tube的吊带连接了下部Anchor。水下操作应该是ROV靠近后，扯掉绑在Anchor上的三根吊带的连接固定限制。
 
 - 2022年的9月份航次，this was achieved at a record-breaking speed, with 7 detection units installed, connected and unfurled in less than 48 hours!
 - 21 in ARCA
 
#### October 2023 ARCA Deployment
 
The campaign was performed with the `Optimus Prime`, equipped with a `FUGRO` underwater vehicle (ROV). 

 <img src="./img/DU-deployment-from-Optimus-Prime-sept2023.jpeg" width="800">
 <img src="./img/ROV-control-room-at-DU-unfurling-sept2023.jpeg" width="800"> 
 
 - 28 in ARCA (看起来是这个航次共布放了7台)

  
#### Dec 2022 ORCA Deployment
  
  During a sea campaign performed last week, ORCA has been enlarged by means of `4 new detection units`.
  The operation was performed with the Castor ship of Foselev, for deployment of the detection units, and with the Janus II of SAAS (formerly Comex), equipped with a deep-sea remotely operated vehicle, for submarine operations.
  
  - 15 DUs in ORCA
  
#### May 2023 ORCA Deployment
  
  During a two days sea operation, 27-28 April 2023, `three detection units` were successfully connected to the ORCA detector of KM3NeT `in a record time of just over 24 hours`.
  As usual, the operation was performed with two ships: the Castor of Foselev, for deployment of the detection units, and the Janus II of SAAS (formerly Comex), equipped with a deep-sea remotely operated vehicle, for submarine operations.
  ORCA的布放是双船联合作业。布放线串列的船和ROV的母船是分开的。
  
  - 18 in ORCA