Differences between AMANDA String 18 DOMs and IceCube DOMs

Basic Technology Departures from AMANDA

• Digitization of waveforms instead of leading edge finding.
• Digitize at the detector instead of transmit waveforms to digitizing equipment in counting house.
• Single board DAQ Computer deployed into the ice.
• Transmission of precision timing information to the detector in the ice.
• Calibration electronics deployed in the DOM (flasher board and on-board flasher)
• Local Coincidence links to neighbors. (single transmitter; directional receivers)
• Power splitter used for directional discrimination on LC receivers.
• Two Gain Channels to ATWDs
• Transmission of digital data and analog waveforms over fiber optic link to counting house.
• Slow and fast digitizing; ATWD and 33.6 megasample per second (MSPS) pipeline, parallel output ADC.
• Transformer coupling of PMT signals to PMT input.

System differences between AMANDA string 18 and IceCube

• Single Pair per DOM; no shared media.
• Greater depth of deployment; greater DOM spacing vertically and horizontally.
• PCI industrial computers in counting house instead of EISA industrial PCs (DOM Hubs).
• Higher channel density in DOM Hub computers. (8 per card vs. 1 per card)
• 0.9mm wire in the transmission line vs. 0.7mm wire.
• Dropped fiber-optic transmission of waveforms to surface.
• Trunking filtered events to the northern hemisphere daily instead of shipping data tapes in Nov.

Board differences between IceCube MB and String 18 MB

• Dynamic RAM (SDRAM) instead of Static RAM (SRAM)
• FPGA and CPU on same semiconductor die (Altera EPXA4 "Excalibur")
  (SOPC: system on a programmable chip)
• Fully independent up and down Local Coincidence links.
• Power splitter used as duplexer.
• Flash File System with multiple configurations and programs vs. monolithic program.
• STF test suite vs. collection of test programs; better testing coverage.
• Annular layout instead of "U" shaped layout.
• Stripline delay line PCB instead of coax delay line.
• Higher digitizing rate; 40 MSPS pipeline, parallel output ADC
• DMA transfer of hits to SDRAM buffer
• Component selection for reliability. (no electrolytic capacitors, etc.)
• Board burn-in and HASS testing
• Digital control and read out of HV board instead of analog control and read out.
• 5 Megabyte Digital expansion bus (utilized by flasher board which is itself an embedded system)
• 100% Allen Variance screened oscillator module.
• 96V system power instead of 72V system power.