LTB Laser @ South Pole
Designed to calibrate the IceCube neutrino detector array
The Standard Candle is a 337 nm pulsed nitrogen laser along with associated electronics and optics designed to calibrate the IceCube neutrino detector array at the South Pole. It was deployed on Wednesday, January 18, 2006 on String 40 of the array and reached its final resting place at 1813 m below the surface of the ice. The Standard Candle uses a reflective cone to simulate the Cherenkov light from an electron-neutrino induced cascade propagating through the ice. Its well-known location and per-pulse energy will be used to calibrate the detector and verify our monte carlo simulation of cascades.
Electronic Components:
The following are the electronic components on-board the Standard Candle:
* 24V DC-DC Converter: Vicor MI-Compac
* 5V DC-DC Converter: Martek Power Abbot Inc. NB15S
* Solid State Relays: Magnecraft 70S2 Series SSRs
* Temperature Sensors: Analog Devices AD22100
* Heating Source: Omega SRT Series Heating Tape
* Laser: Lasertechnik Berlin "Marathon" Nitrogen Laser
* Internal PMT: Hamamatsu H5783 Photosensor Module
* PMT DAQ Board: Photon Systems custom-made
* Computer: Z-World Wildcat (BL2000) Single-Board Computer
* Communications: Nexcomm NM220G Ethernet Extenders
The electronics of the Standard Candle revolve around the Z-World Wildcat single board computer. The computer communicates serially to the nitrogen laser and to the PMT DAQ, reads the temperature sensors, switches relays which control the power to all the devices, and acts as a server to handle commands from the surface and to send data when it is requested and becomes available. Communication with the surface is achieved through a pair of ethernet extenders operating at 512 kb/s. When the power supply at the surface is turned on, the Wildcat and ethernet extenders are switched on in the Standard Candle, and the computer waits for a socket connection to be established. Once the connection is established it responds requests for laser pulses and PMT readings as well as commands to turn on and modify the settings of the various devices. The electronics are also programmed to operate autonomously if a socket connection is not established within ten minutes of the Standard Candle being powered on.
Contact
Dr. Stephan Mory
Senior Scientist
phone: +49 (0)30 6392 - 6175