USA, CA, Bodega Head (sensor 78)
Offline long

5 months ago 5 months ago
83cpm 5492cpm
0.086μSv/h 5.721μSv/h
Sensor:LND78017
Alarm:150

102Seawater Probe (CAL 960 CPM/µSv/hr); Geiger tube is the LND 78017.

Note that CPM readings may be higher relative to North American terrestrial sensors, as the tube used for this Seawater probe is more sensitive than most.

 

Probe with nGeigie. Prior to installation
Probe with nGeigie. Prior to installation

 

 

 

Poly-wrapped Probe in Seawater Sump. Seawater form center of a small bay circulates continuously through this sump. Various other sensors share the sump.
Poly-wrapped Probe in Seawater Sump.
Seawater form center of a small bay circulates continuously through this sump. Various other sensors share the sump.

 

 

Sediment around Probe. Sump and Probe are cleaned periodically. Sump can fill with kelp, sand and small marine organisms, so requires cleanout, especially under rough ocean conditions.
Sediment around Probe.
Sump and Probe are cleaned periodically. Sump can fill with kelp, sand and small marine organisms, so requires cleanout, especially under rough ocean conditions.

16 Responses to “USA, CA, Bodega Head”

  1. Dan Sythe

    The Bodega head sensor became damaged by salt water intrusion when the connector degraded. Please see attached photo. We are going to re engineer the sensor so that this does not happen again. The high readings at the end of its life were due to noise created by the salt water intrusion and not elevated radiation levels.

    Reply
  2. Paul-André

    Why has the Bodega Marine Lab been off site for so long?

    Reply
  3. Dan Sythe

    We are seeing some transient spikes that we think are related to maintenance activities. I am checking with site maintenance crew. The overall background reading has been steady.

    Reply
  4. Dan Sythe

    There seems to be a sporadic noise issue at the site. Will get there as soon as I can to diagnose.

    Reply
  5. Dan Sythe

    Ross diagnosed recent failure, which was due to router failure – possibly due to power surge at probe site. Itʻs back online.

    Reply
    • Bertha

      You may find the OSA screening test at MySlTepeest.com a useful tool. It provides a thorough OSA screening test and provides a very useful report that gets emailed back to the user.

      Reply
  6. Ross

    We are investigating the 3.30.16 outage…

    Reply
  7. Ross

    The building housing this probe is subject to inundation during Pacific storms. This area of California is also prone to loss of electric service each storm season, and backup power to this station may be limited. These factors may have contributed to the data drop-out around Christmas 2015.

    Reply
  8. Kent Noonan

    The geiger tube used here is the LND 78017. 960 CPM/uSv/hr conversion factor.
    Specifications : http://www.lndinc.com/products/406/

    Reply
    • Ross

      Thanks Kent; I added model number next to Cal factor at top here so it remains ‘sticky’.
      Please post about your discovery and examination of the bump in levels beginning early July.
      Our host has responded and will check the installation for anomalies.

      Reply
      • Julissa

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        Reply
  9. Dan Sythe

    For now we are not publicizing the exact location of this sensor, while we work out a formalized agreement with the host and we get through the beta test.

    Reply
  10. Dan Sythe

    This is now live and the oldest portion of archived data is from testing done on dry land with a radioactive source.
    Weʻll be working on cleaning this up. The CPM is higher on this particular GM tube sensor, relative to the pancake detector many of us are accustomed to, due to the larger detector volume. The important data to watch with this sensor is uSv/h, which should be equivalent from sensor to sensor when measuring gamma radiation. Sea Water, being relatively dense, will rapidly absorb beta radiation.

    Reply
  11. Ross

    Was installed Wednesday April 22nd 2015, Earth Day!

    Reply

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