2005-2006 Standard Candle ("Cable Tie")




Summary:

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.

This page is an overview of the Standard Candle. Please follow this docushare link for a more complete collection of Standard Candle documentation.


Data Runs:
Date DAQ IceCube Run# Pulses Frequency Filter Wheel SC Run Log Summary
1/26/06 test 26831 10000 10 5% SC_1138261281.dat SC_1138261281.log SC_1138261281.sum
1/26/06 test 26832 10000 10 0.5% SC_1138263379.dat SC_1138263379.log SC_1138263379.sum
1/26/06 test 26833 10000 10 50% SC_1138265740.dat SC_1138265740.log SC_1138265740.sum
1/27/06 real 20060127_073000 10000 10 100% SC_1138342442.dat SC_1138342442.log SC_1138342442.sum
1/27/06 test 26875 10000 10 100% SC_1138342442.dat SC_1138342442.log SC_1138342442.sum
1/28/06 test 26981 10000 10 50% SC_1138447956.dat SC_1138447956.log SC_1138447956.sum
2/2/06 test 27302 2400 10 100% SC_1138857230.dat SC_1138857230.log SC_1138857230.sum
2/2/06 test 27303 2400 10 50% SC_1138858268.dat SC_1138858268.log SC_1138858268.sum
2/2/06 test 27308 2400 10 0.5% SC_1138867896.dat SC_1138867896.log SC_1138867896.sum
2/2/06 test 27309 2400 10 76% SC_1138868355.dat SC_1138868355.log SC_1138868355.sum
2/2/06 test 27310 2400 10 25% SC_1138870109.dat SC_1138870109.log SC_1138870109.sum
7/7/06 test 30404 2000 2 100% SC_1152247452.dat SC_1152247452.log SC_1152247452.sum
7/7/06 test 30405 2000 2 50% SC_1152248600.dat SC_1152248600.log SC_1152248600.sum

- Click here for sc_extract (V0.1) -

Electronic Components:

The following are the electronic components on-board the Standard Candle:

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.


Surface Software:

The surface software for the Standard Candle was written in Java and the GUI was written in Java Swing. The Java code establishes a socket connection to the device and communicates over TCP/IP. Communications to and from the device are threaded and can take place simultaneously. The status of the device is queried at 3 Hz and the surface software is always ready to display and process incoming data. Click here for a Java archive of the latest version of the surface software (V2.00). Here is a screen shot of the surface software in action:


In-Ice Software:

The in-ice software for the Standard Candle was written in the proprietary Dynamic C programming language from Z-World. The language enhances C by including functions specific to Z-World's selection of single-board computers and microcontrollers. In particular, Dynamic C easily enables cooperative multitasking within a C framework. The purpose of the in-ice software is to coordinate the different devices on board the Standard Candle and to act as a server to respond to commands from the surface. It is also responsible for taking data, timestamping it, and sending it to the surface when it becomes available. The coordination of the electronic components, listening for commands, and sending data and status are all multitasked to allow for independent processes running simultanously. Click here for the latest version of the SC control software (V2.00).


Optics:

Please refer to this docushare link for a complete description of the optics for the Standard Candle under the design document. Here are some pictures of the reflective cone with the saphire window, and the laser output fluorescing on a piece of paper with millimeter markings:


Deployment:

  • Deployment Take 1:

  • Deployment Take 2:



  • Last updated Sunday, January 29, 2006.