It’ been a few months since the last newsletter, and we’d like to tell you some of the exciting things going on with ERGO–
ERGO Worldwide Leaders…
I often use the phrase, “You knew this job was dangerous when you took it.” One of the reasons we took on this work was to figure out how to engage a worldwide collaboration of students and teachers in a scientific project. We’ve found that there are all kinds of problems, but the fun lies in finding solutions. For example, did you know there are some places on the planet where you can’t just send boxes containing electronic instruments? We’ve found at least one country where the US Postal Service won’t send packages, and although Fedex accepted it, our package was returned by Pakistani customs office. There are probably many such places around the world, but right now we’re looking for someone who is traveling to Pakistan and would be willing to help a host there set up an ERGO pixel. In some areas setting up an ERGO pixel might come down to a personal connection with someone there.
As the network expands (we’ve built 119 ERGO pixels now, and over 110 of them have been sent out to hosts), we’ve found that it’s not always easy to set up and to keep a pixel on-line. People move, get promoted, graduate, and other things happen that result in an ERGO pixel either never going on-line or going off-line after it’s originally set up. The solution to these problems is communicating with the hosts, and we needed a way to “scale” beyond what one person could manage with emails and phone calls. So, we’ve divided the world into five areas, and we’ve got volunteers to be leaders for those areas:
• South Florida (we have a lot of pixels in a cluster here)—Sloane Rice
• Americas (outside S. Florida)—Jordi Orbay
• Eurasia—Alan Garrett
• Middle East—Alan Garrett
• Asia-Pacific—Alan Garrett
• Africa (well, we’re hoping to get some pixels there, but we need some help)
Sloane, Jordi, and Alan have started to make connections with all our hosts in their areas, and we’re starting to see results as pixels come on-line.
ERGOduino, the Do-It-Yourself Pixel
Last summer we realized it was time to design a new, much-less-expensive pixel. What if we could make it “open-sourced,” so anyone could build their own pixel? We looked around to see what microcontroller architectures were available, and we decided on the Arduino platform (specifically, the Arduino Ethernet). The Arduino community is a vast, creative group of people who build and program electronic control systems for all kinds of things, from cat feeders to MP3 players. The simplest Arduino costs under $US 20, and the Arduino Ethernet, which includes micro-SD storage and Ethernet connectivity, costs around $US 60. So, you can buy an Arduino Ethernet board, connect a GPS receiver and muon detector, add some software, and you have an ERGO pixel! Since most things designed for Arduino are named something followed by “uino,” we’re calling it the ERGOduino.
In order to simplify adding the GPS and detector we have designed a “shield” (an add-on board for the Arduino) that includes everything you need except the detector. The shield includes a Radionova GPS 12-channel receiver (with built-in nanosecond-level timestamping!) and circuitry that can accept signals from just about any kind of detector you could imagine. The total cost of parts for the shield is around $30. The Radionova GPS has its own built-in antenna, but you can connect an external antenna if that works better in your installation.
We have the shield hardware pretty well developed, but that leaves one important piece: the software. Jim Brown of seti.net has been working on that part, and he’s very near to a solution. The software has to read in the GPS location and timestamp data from the Radionova GPS when an event occurs and format the data properly for “posting” to our database server. The database has been moved to our own dedicated server at a co-location facility, and it’s being administered by James Riley at betaforce.com. We look forward to trial operation of the ERGOduino very soon.
If you’re interested in helping develop the ERGOduino, let us know. A follow-on project might be a similar system based on the Raspberry Pi, a very powerful, cheap, and versatile new open-source platform.
The ERGOnaut—Our Deep-sea Diver
You might have been following our experiment to place an ERGO pixel very deep underwater. Last November we took the ERGOnaut 1 on our research ship, Patent Pending, for its first sea trial. Our plan was to drop it on a tether to -850 meters, but we found the seas too rough on the day we sailed, so we re-located to a better-protected site just east of Elliot Key with a depth of 150 meters. Well, it’s still there. Our winch control failed, and the ERGOnaut 1 dropped all the way to the bottom, where it got snagged. All our efforts to pull it loose failed, so that’s where it lies. If anyone wants to dive to 150 meters to retrieve it, we’d sure like to see the data recorded on the internal memory card and the video from its on-board camera. But, unfortunately, that depth is just beyond where scuba divers can go. Does anyone have an ROV that can go to that depth?
But, we never give up, so we’re planning to build a second diver, the “ERGOnaut 2,” to try it out this summer. Stay tuned….
A Few More Beta-4 Pixels
Following a mention of ERGO in the Bad Astronomy blog we received many inquiries from people who wanted to participate in the project, but we were running out of the initial Beta-4 ERGO pixels. While we are developing the ERGOduino low-cost pixel, we decided to build ten more Beta-4 pixels to meet the demand. The ten circuit boards have been fabbed, five have been built, and three have been sent out to Norway, New Mexico, and New Jersey. Look for them on the ERGO map. We have five Beta-4 pixels remaining to build, and we hope to have the ERGOduino ready by the time those run out.
Cosmic Rays and Lightning
One of our high-school students, Troy Gonzalez, has been working on our project to see if we can establish a correlation between cosmic-ray air showers and the initiation of lightning bolts. Atmospheric physicists think the voltage gradients in storm clouds, even though they are millions of volts, aren’t great enough to initiate a lightning discharge hundreds of meters in length. Various theories have been advanced, but the leading one is that when the electric field becomes strong enough at a particular space where a cosmic-ray air shower occurs, the ionized paths created by the passage of cosmic-ray muons through the atmosphere form a path for the initial lightning discharge. The process is known as “runaway breakdown” (see the article in Physics Today: “Runaway Breakdown and the Mysteries of Lightning”.
Troy has completed building five lightning-detection circuits, which we have married to five ERGO timestampers (basically, an ERGO pixel without the Geiger-Müller detector). Lightning discharges send out radio impulses, and Troy’s detectors pick up those impulses to trigger an ERGO pixel, which reports the exact time and location where the impulse was received. Once we have the five detectors installed around South Florida, we’ll be able to determine the exact time and location of lightning discharges by a process called Time-delay-of-arrival Multilateration. Then, it’s just a matter of waiting for some lightning bolts to appear in close proximity to some of our ERGO cosmic ray detectors and see if there were cosmic-ray air showers detected at those times and locations. If we can do it, and if we can establish a statistically-significant correlation in space and time between lightning discharges and cosmic rays, it will be new science.
Troy has applied to take his project to the International Science and Engineering Fair, so wish him luck!
All the Beta-4 ERGO pixels have incorporated a Geiger-Müller (G-M) tube muon detector. Although G-M detectors are inexpensive and reliable, there are two problems with that choice. First, they are physically small, which gives them a very small “window” that is sensitive to muons. It would be great to have a larger detector area in order to catch more muons. Second, it would be better for ERGO pixels to have a detector that is sensitive to high-energy cosmic muons but not sensitive to the lower-energy terrestrial background radiation. That way, we would be counting only cosmic-ray events.
Early in the project we tried to develop “resistive-plate chamber” (RPC) detectors, such as those used at accelerator labs, but we were unable to produce them reliably. A new type of detector, the Gas Electron Multiplier (GEM) has been developed recently by scientists at the Large Hadron Collider, and it could possibly be a good path to a larger, muon-only detector for ERGO. Does anyone want to try to make one? Here’s a reference: GEM Detectors.
Simon Tsaoussis has been working on another type of detector, using a plastic scintillator (available cheaply as surplus) and a PIN diode (a sensitive kind of photodiode). Simon is working on prototyping one on a tiny circuit board. He wants to build it into a cellphone!
And That’s the Way It Is—
Thanks to all the interns and volunteers for all the work they have done. I think you’ll agree, if you’ve read through this long-winded newsletter, that we’ve made a lot of progress!