Here are some of the articles that have been recently posted to the PASSCAL website:

Updated Instrument Response for Trillium_120, Trillium_240 (2 Generations) and Taurus

Instrument Response files released from Nanometrics for Trillium 120 and Trillium 240 sensors have been evaluated and updated for Antelope, where they are used to generate dataless and RESP files.

Trillium Releases Updated Response Files for Trillium 120 and 240

Nanometrics Inc., manufacturer of the Trillium series of broadband sensors, has recently updated the response for Trillium models 120 and 240.

EPIC provides these new response files for Antelope in our FTP download area.

A new posting, "Updated Instrument Response for Trillium_120, Trillium_240 (2 Generations) and Taurus", provides information and links to Antelope response files; it is available here.

If you have questions about using these new response files, please contact pmiller [at] passcal [dot] nmt [dot] edu (Pnina Miller) of the Sensor Group.

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Mendenhall Glacier, Up Close and Personal

EarthScope/EPIC has been a key supporter of a novel deployment of equipment at Mendenhall Glacier in Alaska.  A team of researchers from the University of Alaska Southeast, the University of California Santa Cruz, and the Alaska Science Center in Anchorage have been performing an ambitious analysis as part of a low-budget cutting-edge project. Above, a Trillium Compact AT is lowered directly into a borehole in the glacier.

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Solar Mounts

GROUND MOUNTS

65 Watt Single OR Dual Solar Panel Ground Mount Setup. Single panel is pictured below; a second panel can be mounted below the first. There is (a limited) angle adjustment range.

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Power Box Equipment for Summer Only Enclosure

Solar Charge Controllers

The Solar Charge Controller is responsible to properly charge the batteries when solar energy is available.  The GenaSun GV-4 controller, which is used for summer only experiments,  is a very efficient charge controller that uses the MPPT (Maximum Power Point Tracking) to maximize the power available at the solar panel, increasing the efficiency by 10 to 30% over traditional solar regulators.  It also uses very little power in low or no light conditions.

Power Box Equipment for Year Round Polar Programs

The Extreme-Cold Temperature Power Management Module for Year Round Use

EPIC's Polar Group specifically designed a power management module to control the charging and manage the power system in extreme-cold temperature environments. There are two main parts in the power box:  The solar charge controller and the power switcher.  The solar charge controller, as the name implies, takes care of the proper and efficient charging of the batteries when solar energy is available.  The power switcher takes care of switching from the rechargeable batteries to the primary batteries when the rechargeable batteries' voltage dips below a threshold, and switches from the primary batteries to the rechargeable batteries when the rechargeable batteries' voltage gets high enough from solar charging.  Both the charge controller and the power switcher were tested successfully for operation at -55C after having been subjected to -70C for several hours.

Summer Only Enclosure for Polar Projects

Here are several documents regarding summer-only equipment for Polar Projects. Batteries DAS Power Sensors Solar Station Enclosure Vaults

Specialized Polar Equipment

The Polar Program of EarthScope/EPIC is dedicated to supporting with seismological research in the Arctic and Antarctic.  As opposed to traditional seismic stations installations around the world, instrumenting the Arctic or Antarctic require special consideration due to the extreme nature of the climatic conditions, temperature being the primary challenge.

Station Enclosure Drawings

Station Enclosure Drawings   Large Enclosure:  Insulated Hardigg AL3434-2807 External dimensions:  37" x 37" x 37" Internal dimensions:  24" x 24" x 21" 2" thick vacuum insulation panel (VIP) sub-enclosure Protective polypropylene barrier between VIPs and electronics Integrated cable harness with external bulkhead connectors Year round operation with rechargeable AGM batteries   Detailed Drawings Hardigg AL3434-2807 Insulated:  Assembly Drawing with BOM

Working with Responses to Get Units of Ground Motion

Necessary information:

Sensor: sensitivity and passband (velocity transducer) or scaling (accelerometer)

For information on sensor sensitivity and passband, see the Sensor Comparison Chart along with the Sensor Response Plot.

Datalogger: Analog-to-Digital (A/D) conversion factor (aka bit weight) and Gain 

Quanterra model Q330: 419,430 counts/volt, or 2.384 uV/count at a Gain of 1 RefTek model RT130: 629,327 counts/volt, or 1.58997 uV/count at a Gain of 1

 

Example: Counts to Ground Velocity Conversion within the Passband