Monday, November 30, 2009

Today in Christchurch

Christchurch is a beautiful city, with a lot of beautiful old stone buildings. This picture shows the main cathedral, next to a "The Chalice," (possibly better known as "The Ice Cream Cone").

At breakfast, I ran into Laura Gladstone, a UW (Madison) graduate student on IceCube; she is on her way to the South Pole to test digital optical modules (DOMs). Laura, Thorsten and I then went to the University of Canterbury, where we lunched with the local IceCube group. This is Suruj Seunarine last week there - after 9(?) years he is moving to a faculty position at the University of the West Indies, on Barbados.

After lunch, the main event was our appointment at the Clothing Distribution Center (CDC), where we received everything from long underwear and wool socks to warm parkas and snow goggles. And again, more pairs of gloves and mittens than I knew what to do with - leather mittens, 2 pairs of leather gloves (I gave one back), snow gloves, glove liners.... Since we had to try everything on, this took some time.

Later, Thorsten and I wandered around the Christchurch botanical garden, which is really amazing. Especially the heritage rose garden (below):

There is also a nice display of water plants (below):

We need to be back at the Antarctic center at 6 am tomorrow, for a planned 8:30 (?) departure.

Halfway (?) There

After a long flight and a few adventures, we made it to Christchurch, NZ.

The fun started at SFO. I had no problems, but Qantas (Australian airline) had real problems with Thorsten's boarding passes. At the check-in counter and gate, we heard a string of improbable excuses: You need to get electronic visas for Australia (at a cost of $25) [even though we never went through Australian immigration], New Zealand Immigration thinks that your passport has expired, and, finally, there isn't enough time for him in Sydney between flights [then why did you sell us this ticket? Maybe they think I can run faster than him]. In the end, they gave him a SFO to Sydney boarding pass and told him to try again in Sydney. They also checked all 3 of our bags on my ticket [the alert reader will note a bit of literary foreshadowing here].

The flight to Sydney was as nice as a 14 hour flight can be. The plane was about 1/3 full so we had room to stretch out, there were only a few crying babies, and the food and entertainment system were a cut above most U.S. airlines [n. b. this was a code-share flight and we had "American Airlines" tickets, so satisfied the "Fly America" act]. Due to winds, we took a very westerly route, flying by Hawaii, and then south over the Solomon Islands. Unfortunately, the sun was just coming up,and we couldn't actually see any islands.

In Sydney, we had 40 minutes between flights - plenty if we both had boarding passes. The Qantas "Transit" Desk first ascribed this to NZ immigration, and then said "This happens now and again," and, after a few tries with unanswered phones, was able to reach a supervisor who could override the hold, and print a boarding pass. Thorsten was the last one on board.

After another 3 hours flying, we arrived in Christchurch, went through immigration, and waited for our bags. And waited. And waited. It seems that our bags like Sydney so much that they decided to take a later flight. Unfortunately, our oscilloscope, which requires special customs clearance, was in one of the three bags, checked in my name, even though the customs form listed Thorsten's name. And, we didn't even know which luggage tag it was. As a further complication, we used the same customs form for our carry-on network analyzer (no traveler should be without one). After some confusion, this was at least theoretically sorted out, and the oscilloscope will clear customs and our bags should be delivered to our hotel tomorrow morning.

Fortunately, the FedExed ARIANNA electronics box did arrive and cleared customs, and it scheduled to be on our flight South.

Christchurch hasn't change much in the past year and a half. It is still a very visitor-friendly (and generally friendly) place. Unfortunately, today is cold and slightly rainy (even though it is summer here). And my umbrella is still in Sydney.

Friday, November 27, 2009

Getting There is half the fun

An influential reader (full disclosure: my wife) thought that it would be helpful if I posted a map of Antarctica, showing where we're going. We will be on the Ross Ice Shelf, near the bottom of this map. Initially, we will be based at McMurdo station, shown by the red dot. This is the main U. S. base in Antarctica, a major logistical hub. There, we will go through "Snow School" and other training, gather our food, tents, generators, other equipment, etc. Then, we will be helicoptered to Moore's Bay, about 70 miles away. Very roughly, it is below and to the right of the "F" in "Shelf".

We will travel there via New Zealand. We will fly from San Francisco to Christchurch, NZ, via Sydney, Australia (not the most direct route, but at least it's only one stop), crossing the international date line and arriving Monday morning. On Tuesday, we will go to the Clothing
Distribution Center (CDC), where we will be issued a full range of cold-weather clothing. On Wednesday, weather permitting, we will fly down to McMurdo, most likely on an air force C-17.

This photo, from 2006, shows the C-17 that I flew on to McMurdo, for a trip to work on IceCube. Then, we flew C-17s to McMurdo, spend the night there, and then continued to the South Pole on an LC-130, which landed on skis. The bottom photo shows an LC130 landing at the Pole, also from 2006.

Wednesday, November 25, 2009

The Tip of the Iceberg

I’d like to give you some idea of the huge amount of effort that it takes to make a scientific endeavor like this a success. Our time in Antarctica is just the tip of the iceberg; a large number of scientists and engineers have contributed to ARIANNA. Equally importantly, many, many people have been working behind the scenes to provide the logistical support. Without enough food, fuel, clothing, equipment, power and transportation, this would be an uncomfortable and unproductive trip.

Although we will only be in Antarctica for a few weeks, preparations began many months ago. Special mention goes to Steve Barwick (UC Irvine), who is the ‘father’ of ARIANNA. He and Dave Saltzberg (UCLA) visited Moore’s Bay in 2007 and made initial measurements of the how radio waves propagated through the ice and reflected from the ice-water interface. Steve described ARIANNA in preprint arXiv:astro-ph/0610631.

Steve arranged this trip with the National Science Foundation (they run the U.S. bases in Antarctica) and with Raytheon Polar Services Corporation (RPSC; they operate the bases). RPSC provides everything from laboratory space to food and fuel to transportation and internet access. The US Air Force chips in with flights to/from Antarctica.

At LBNL, we have focused on getting the prototype station hardware ready to go. The picture (above) shows Thorsten with the electronics box. It uses electronics from the ANITA balloon experiment, converted by Steve and his collaborators for use in ARIANNA. Steve provided new antennae, and we added new RF preamplifiers and lower powered GPS receivers and updated the Field Programmable Gate Array (FPGA) firmware. Lisa Gerhardt (LBNL) and Ryan Nichol(University College, London) wrote new software. Steve and his student, Jordan Hanson, even brought the solar panel, wind generator and associated tower up to LBNL and guided us through assembling it.

We also spent much time trying to think of everything that we will need in the field, since what we take is what we’ll have. There are no equipment piles, useful junk, or next-door labs to borrow an oscilloscope (or even a screwdriver).

We also had to undergo thorough medical and dental checkups, including many, many blood tests, and an EKG. There were also on-line courses on Antarctic ecology and adhering to the Antarctic treaty, and on computer security.

These preparations are the building blocks for a successful season; hopefully all of this work will pay off.

Monday, November 23, 2009

Why we are going to Antarctica

This blog will be an account of my trip to Moore’s Bay, on the Ross Ice Shelf in Antarctica. Thorsten Stezelberger (an LBNL Engineer) and I are going there to study the site conditions and test prototype electronics for ARIANNA, a proposed experiment to look for radio pulses produced by neutrino interactions in the Antarctic ice. I will try to capture the adventure of traveling to Antarctica and camping out on the ice, while also giving you and idea of why this crazy trip is worthwhile, scientifically.

We plan to leave Berkeley on November 28th, and fly via Christchurch, New Zealand to McMurdo Station, in Antarctica. There, we will attend “Snow School,” (aka survival training) and gather our equipment, before being deposited by helicopter on an empty patch of ice in Moore’s Bay, about 70 miles from McMurdo, where we will camp on the 650 m thick Ross Ice Shelf. We plan to spend 10 days in Moore’s Bay, characterizing the ice (e.g. measuring the radio wave reflections from the ice-water interface, etc.) and setting up a prototype radio detector which will be left in place for a year. Of course, plans sometimes change quickly in Antarctica.

The prototype is one step toward ARIANNA, a proposed array of about 10,000 stations, covering roughly 900 square kilometers. Each station will consist of 8 TV-like antennae embedded in the ice, connected to an electronics box containing trigger electronic and waveform digitizers. The whole thing will be powered by solar panels in the summer (when the sun is continuously above the horizon). For the winter, we are testing a wind generator, but this will place stringent limits on station power consumption.

The ARIANNA detectors search for radio waves produced by neutrino interactions in the ice. The radio pulses come from the particle showers produced when occur when the neutrino converts it’s energy into matter, creating a shower containing up to a trillion particles. The showers contain more electrons than positrons (because some of the photons Compton scatter from atomic electrons in the ice). The moving charges emit Cherenkov radiation. For radio wavelengths longer than the shower diameter, the radiation is coherent, producing large signals in the 50 MHz to 1 GHz frequency range. The signal size rises as the square of the neutrino energy; ARIANNA should detect neutrinos with energies above 10^17 eV.

We use these neutrinos to probe the high energy cosmos, to find the origin of the high energy cosmic rays that have been observed by surface air shower arrays like Auger. ARIANNA will complement smaller neutrino detectors like the 1 cubic-kilometer IceCube array which is optimized for lower energy (10^11 to 10^17 eV) neutrinos.

Thursday, November 19, 2009


ARIANNA is in some sense a follow-on experiment to IceCube, a neutrino detector that is now being built at the South Pole. IceCube also looks for Cherenkov radiation from the charged particles produced in neutrino interactions. However, Icecube looks for visible light Cherenkov radiation, while ARIANNA looks for radio waves. IceCube is smaller than ARIANNA, and optimized for lower energy neutrinos.

The IceCube detector consists of one cubic kilometer of ice, just North (about 2 km) of the South Pole, where the ice cap is 2800 meters thick. We are building it (it's about 2/3 done) by drilling 86 holes, each 2500 meters (more than a mile) deep, using hot water to melt our way through the ice. We then lower strings of 60 very sensitive optical detectors into the holes, instrumenting the bottom 1,000 meters. LBNL built the data acquisition electronics for these modules, and is also very involved in the software, calibration and data analysis. Our main physics goal is to search for sources of high-energy (above 100 GeV) extra-terrestrial neutrinos. We also study a wide variety of other physics, ranging from searches for hypothetical particles like magnetic monoples, or different models of dark matter, to studies of the composition of cosmic rays. The latter study uses an array of surface detectors, IceTop to detect cosmic-ray air showers; we use the buried optical sensors to study high-energy muons in these showers. IceCube is being built to the right of the ski-way in this photo; the station living areas are to the left.

There are some photos here, a 'travelog' here, and links to other photo collections here.

n.b. I am editing this post on Nov. 27th,to fix a bad link, pointed out by Bob Stokstad.