IceCube Upgrade

The IceCube Neutrino Observatory is the first detector of its kind, designed to observe the cosmos from deep within the South Pole ice. Encompassing a cubic kilometer of ice, IceCube searches for nearly massless subatomic particles called neutrinos. Because neutrinos rarely interact with matter and can travel across the universe largely undisturbed, they provide scientists with valuable insight into some of the most energetic and distant events in the cosmos.

On June 25, 2019, the National Science Foundation (NSF) approved $23 million to upgrade the IceCube detector, extending its scientific capabilities to lower energies and enabling IceCube to reach neutrino energies that overlap with the energy ranges of smaller existing neutrino detectors worldwide. The IceCube Upgrade built upon the original IceCube (Gen1) detector by installing six new strings of optical modules within the existing array of 86 strings, adding more than 500 new and enhanced optical modules to the 5,160 sensors already embedded in the ice while having recalibrated the existing detector which improved its overall performance.

Scientific Objectives

Drill Evolution

Field Seasons

Controls System Upgrades

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Scientific Objectives

The Enhanced Hot Water Drill equipment from IceCube construction was resurrected to support drilling operations for the Upgrade. Much of this equipment was long-term stored at South Pole since completion of IceCube construction in 2010-11, and some subsystems needed major upgrade work and/or needed to be replaced completely.

This initiative deployed 500 advanced photodetectors and calibration devices inside the existing IceCube detector. The new instrumentation improved our understanding of how the light emitted by neutrino interactions in the ice travels throughout the detector, effectively bringing the neutrinos into sharper focus. The IceCube Upgrade allowed us to increase the sensitivity of the present telescope. The sharper resolution achieved through the upgrade can be retroactively applied to data already acquired and stored during the first decade of IceCube’s operation, which immediately provided a major improvement in IceCube’s sensitivity.

In addition, new sensors have provided a unique opportunity to measure the properties of neutrinos, the least understood of the fundamental particles discovered to date. Cosmic ray interactions in Earth’s atmosphere provide copious natural sources of neutrinos. As neutrinos travel through space, they change from one type to another—a purely quantum-mechanical process known as neutrino oscillation. The IceCube Upgrade provided the first precision measurement of the number of tau neutrinos appearing as a result of these oscillations. A measurement inconsistent with the poorly constrained current theory would be a smoking gun pointing to undiscovered types of neutrinos or to new physics.

Gen1 EHWD to ICU Drill Evolution

The Upgrade Drill is a refurbished version of the Enhanced Hot Water Drill (EHWD) used to drill the 86 pre-existing IceCube holes. Much of the EHWD was left at the South Pole at end of drilling in 2011 and needed evaluation and refurbishment. Some of the equipment went to other projects such as WISSARD and needed more substantial rework or complete replacement. Many people that worked on EHWD design fabrication and operation were on the ICU drill team.

PSL has a long history of success in hot water drilling and has demonstrated repeatable drilling and installation operations for up to 20 holes in a single season. Between 2005 and 2011 PSL progressed from drilling one hole in the first season to 20 holes by 2010.

Credit: Dr. Kathie L. Olsen, National Science Foundation

Field Seasons

Field Season 1 (2023-24)

Overview

→ IceCube Upgrade team returns to work in Antarctica

→ Cargo deliveries and ASC support provided were critical to field season success.

→ Drill Team Population is 11, entire team will work on one daytime shift

Highlights:

Drillers will work at Cryo worksite upgrading EHWD subsystems
Begin the repairs and upgrades identified in the 2019-2020 season
Integration work on IceCube Generators and Power Distrubution Module (PDM)
Commission Independent Firn Drill (IFD)
Commission Antarctic Rodwell Apparatus (ARA) Drill
Drill South Pole Station outfall with IFD and ARA
Stage EHWD Mobile Drill Structures (MDS) at the Seasonal Equipment Site (SES)

Field Season 3 (2025-2026)

→ Early season EHWD commissioning

→ Full system hot water test (SES-Reels)

→ Drill Upgrade holes (6x) and deploy instrumentation

→ Decommission EHWD

Highlights:

ARA integrated into EHWD for Rodwell use
Cable-hose synchronization
New Ignition software used for drill controls
Six Upgrade holes drilled up to depths of 2600m
New drill techniques exercised
New drill team lead aided by minimal Gen1 expertise
EHWD successfully resurrected

Field Season 2 (2024-2025)

Overview

→ Complete EHWD repairs and upgrades

→ Full system hot wet testing

→ Drill Firn holes (9x) with IFD

→ Drill condensate bulb with ARA

Highlights:

SES fully connected
System wet test at nominal drill conditions (1100 psi, 88C, 200gpm)
Piecewise validation of whole system
Reel motion control
Spool new IVG hose onto DSHR
Setup TOS over Rodwell firn hole
Full system wet testing
9 days
High fidelity on-the-job training
Drill at Firn holes (9x)

Controls Upgrade

Building on control strategies utilized during Gen1 and the planned ICU drilling efforts, the IceCube-Gen2 hot water drill control, communication, and monitoring system was upgraded based on standard automation models used across industrial, production, and public utility infrastructures. The core of the system employed a distributed control system using commercial off-the-shelf hardware controllers (PLCs) which were custom configured and programmed for the IceCube-Gen2 drilling effort. The first table below shows how the control system has changed over the generations of IceCube.

Main duties of the control system included:

Monitor operation of all subsystems
Log operation of all subsystems
Safety interlocks
Alarms
E-stop system
Limited level of active control, 1x control loop (load share)
The control system provided a safe means for the drill operators to make informed operational decisions and act upon them.

Network Layout

All inter-MDS communications were carried over standard Ethernet connections. Base network speeds started at 100~M Bits Per Second (bps) and scaled to 1000~Mbps (1~Gbps) depending upon the device. A hub and spoke topology ensured optimal, collision-free throughput between the system core in the DCC and other MDS instruments. Industrial-class network devices (switches) were placed within each MDS to support the communications backbone. The Common Industrial Protocol (CIP) was the standard data transport. A configurable, enterprise-grade security appliance to block unwanted network traffic (e.g., firewall) was placed in front of the network to harden access to the system.

Software

Custom application software was required to optimize performance of the IceCube-Gen2 control hardware for the drill. Software was written within hardware-compatible development environments to allow for the most seamless integration between controllers, sensors, and actuating devices. A top-down design strategy using industry-accepted SCADA frameworks and software did allow system developers to adopt a modular approach to mapping individual subsystem functions. Revision control was provided using a mixture of vendor and standard solutions. Data archiving was achieved using commercially available solutions.