A cosmic ray shower.
Editor’s note: Bob’s most excellent particle detector adventure, part 7.
Bob Peterson continues to travel with his QuarkNet particle detector around the edge of Africa recording remnants of cosmic rays. This offers a chance to study how cosmic ray recordings differ on land and sea and at different latitudes. The data will be accessible to high school students and teachers in several countries who use similar detectors to learn about particle physics.
Read his previous posts here: The voyage begins, Turning the detector on, Other science on the sea, Particle detectors don’t like light, Enduring a branding for science, A teaching moment on the ocean.
11 May 2011
R/V Polarstern
Latitude: 30-56.1 N
Longitude: 14-27.0 W
off the Moroccan coast
Ship course 017° T
Ship velocity 10.8 knots
10 May:
Dawn; the forecast called for a sunny day? What’s that cloud bank out my cabin window? Oh, wait, that’s land! Ah, the Canary Islands right on schedule just as the navigator predicted, and we approach Las Palmas harbor from the south.
The Polarstern receives the pilot at 0945 (he’s late), and the ship proceeds cautiously into the slip. Forty-five minutes later, dock lines are thrown and we are winched tight to the quay and the gangway lowered.
We are here to receive new scientists from Alfred Wegner Institute, or AWI, coming onboard for special training in echo acoustics and bottom profiling. And it gives some of us a chance to feel land. Shore leave is two hours; be back by 1400 or the captain will not be happy. So, I escape. Sure enough the land is moving in a wave-like motion. I must have sea-legs.
Underway again at 1745. The pilot was late again. By 1830, the Canary Islands are falling behind and slipping into the sunset haze.
How IceCube works. Credit: IceCube collaboration
11 May:
Daily, the Polarstern weather technician, Klaus, launches a weather balloon for upper-atmosphere soundings. Michael Walter, my contact from DESY/IceCube, needs these data. I’m intrigued, so Klaus gladly offers to train me to ready and launch the balloons. This will be fun.
All over the world, weather stations and ships launch these balloons simultaneously, and they need to be at 10 kilometers, or 6 miles, altitude by 1200 Coordinated Universal Time, or UTC. So, Klaus prepares and launches the balloon one hour before because it takes that long to reach 33,000 feet. The balloons are filled with helium to about five feet diameter and carry a small data collection transponder called a radiosonde.
Launchings on land are straight forward; the technician steps out of the filing garage and let’s go. On ship, it’s anything but simple. The deck is pitching and rolling, the forward speed sweeps the deck with maybe 35 knots of wind, and the tall crow’s nest in the center of the ship is definitely in the way. There will be no end of grief from the crew if I hang the balloon there. So, Klaus coaches (and laughs) as I learn to manage the recalcitrant, reluctant object, but I’ve now mastered the preparation and launch. Launchings are analogous to a young boy throwing a rock off a cliff; except, it defies gravity. What fun to watch it sail away. I wonder how long I can still see it before it disappears into the haze.
The data returns to the ship in one-second intervals, showing the profiles of atmosphere parameters. The soundings return data on altitude, pressure, temperature, humidity and wind speed and these data might couple to the QuarkNet cosmic ray muon detector (CRMD) data. Michael Walter will use this to correlate to the cosmic ray flux, or flow rate of cosmic ray remnant particles passing through various areas of the sky. I hope that QuarkNet students can do the same. I, too, will return home with the large data sets to compare to the onboard QuarkNet detector.
Glossary:
*Quay: Pronounced “key”. A concrete, stone or metal platform lying
alongside or projecting into water for loading and unloading ships. Similar to a
pier.
*Pilot: a master mariner hired by the captain to guide a big ship into confined harbors. They have special local knowledge and training. Still the ship’s captain is ultimately responsible. A pilot job is nice if you can get it, because all have to wait for the pilot. They are notoriously late.
*Winch: A hauling or lifting device consisting of a rope, cable or chain winding around a horizontal, rotating drum, turned by a crank or by a motor or other power source.
*AWI: Alfred Wegner Institute – Research facility that owns and manages the R/V Polarstern.
*UTC: Coordinated Universal Time
*Radiosonde: An instrument carried by balloon or other means to various levels of the atmosphere and transmitting measurements by radio.
*Crow’s nest: A shelter or platform fixed near the top of the mast of a vessel as a place for instruments or lookout.
–Bob Peterson
Tags: Bob's boat blog, cosmic rays, education, IceCube, Intensity Frontier, neutrinos, QuarkNet
