Jeffrey Donenfeld

Category: News

Getting To The Heart Of The Keck Array Microwave Telescope: Cryostat Disassembly
This week, I was fortunate to be given unprecedented access to the Keck Array Microwave Telescope in the MAPO Observatory at the Amundsen-Scott South Pole Station by the Keck Array Science Team, in order to witness the disassembly of two of the five cryostats that form the telscope array. Photos.

The Keck array is a microwave telescope, just like Bicep2 and the South Pole Telescope (SPT). However, Keck (or SPUD, as some call it, depending on which side of the funding table the person you’re asking is sitting) is special. Keck, in an effort to up sensitivity and resolution, has taken the best of all worlds, and combined them into one super-telescope. They’ve taken the extremely successful and proven focal plane design from Bicep2, as well as the extremely efficient and self contained pulse-tube cooled cryostat from SPT, and made it into their own super telescope. And then multiplied it by five.

The Keck has not one, but five identical cryostats, each housing its own focal plane. Having five instead of one gives the team an incredible amount of sensing options and flexibility. One distinct advantage that I was able to see up close and personal is that individual parts can be serviced and worked on without bringing the entire telescope to a halt.

More info on the Keck Array:
This past week, the Keck Array science team removed two of the five cryostats, and left three in place and operational.

Here are a few photos of the disassembly of the cryostats, stripping away all of their shielding and refrigeration to get to the heart – the focal plane.

Photos from the disassembly…

Keck Array is housed in the MAPO Observatory, a 15 minute walk from the Amundsen-Scott South Pole Station. Although it’s only a short ways away, in -40 degree F temperatures, full sunlight, driving wind, and an active ice runway to cross, full gear and extreme caution must be used on the walk across the ice. It feels a bit like walking to class – although much colder. And at one of the most remote spots on the planet. That big plywood cone in the background in the groundshield of the telescope.

Looking straight up inside the telescope, as Scientist Colin Bischoff explains the inner workings.

https://flickr.com/photos/jamfan2/8229064838/in/set-72157632128663490/lightbox/

Before disassembly, the cryostats are inspected for defects or light leaks.

Disassembly begins – very slowly and carefully – each cryostat is custom built and unique, the result of thousands of hours of R&D.

The team mid-project. I even got to help out a bit!

The inner core is revealed. This is the core refrigerator that’s responsible for cooling the focal plane down to an incredible 250 millikelvin. That’s just barely above absolute zero. The refrigerator uses both commonplace Helium-4, as well as exotic Helium-3, which is contained within the smaller titanium pressure vessel in the close-up shot.

And finally, the heart of the beast – the focal plane. These four panels sense polarization of focused microwave radiation using chips filled with TES Bolometers. More info on Bicep2 and Keck’s TES Bolometers from NASA JPL:

Transition edge sensor (TES) bolometers sense small temperature changes that occur when photons are absorbed and converted to heat. The use of TESs enables arrays with a much larger number of pixels than is practical with spider-web bolometers. Sustaining its leading role in superconducting TES array technology, MDL developed and continues to improve a process to create arrays of thousands of TESs with high yield (>90 percent). These arrays are being employed on three major astro physics projects, all with the same goal: generating detailed maps of the polarization of the cosmic microwave background (CMB).

https://flickr.com/photos/jamfan2/8229070600/in/set-72157632128663490/lightbox/

That’s it. Thanks very much to the entire Keck Array Science Team for generously inviting me into their lab.
2012-11-28
Refilling the Liquid Helium of Bicep2

A week or two ago, Physicist Jon Kaufman gave me a brief tour of the Bicep2 Microwave Telescope, operating here at the South Pole. Aa I reported earlier, the telescope operates at a very very low temperature – only a few millikelvin above absolute zero. In this particular telescope, to get down to that temperature, liquid helium is used in a series of nested cryostats – each reducing the temperature further. In order to maintain the cold temperature needed, liquid helium must periodically be added from an outside source. A few photos of Jon performing a recent refill of liquid helium:

Here’s what the master control console looks like.

Jon taking a few notes before beginning the fill

That grey puff coming out of the tip of the filling hose is actually liquid helium. Strangely, as we were working around the telescope as it was off-gassing lots and lots of helium, we could breathe in deeply near the vent hose (warmer, gaseous helium) and our voices would get high – just like sucking on a party balloon.

The exhaust hose gets so cold that it actually condenses gas from the air into liquid. That’s liquid nitrogen and oxygen (and a blend of others) dripping off the hose.

A quick trip up to the roof just to check things out on a nice day. This is a look inside the groundshield, at the moveable top of the telescope.

2012-11-27
The South Pole’s Campbell–Stokes Sunshine Recorder

High up on the roof of the incredibly sophisticated Amundsen-Scott South Pole Station, there exists an extremely low-tech piece of equipment: The Campbell-Stokes Sunshine Recorder. Photos.

From Wikipedia:

The Campbell–Stokes recorder (sometimes called a Stokes sphere) is a kind of sunshine recorder. It was invented by John Francis Campbell in 1853 and modified in 1879 by Sir George Gabriel Stokes. The original design by Campbell consisted of a glass sphere set into a wooden bowl with the sun burning a trace on the bowl. Stokes’s refinement was to make the housing out of metal and to have a card holder set behind the sphere.

The unit is designed to record the hours of bright sunshine which will burn a hole through the card.

This basic unit is still in use today with very little change. It is widely used outside the United States, where the Marvin sunshine recorder is generally the instrument used by the National Weather Service.

A few photos of the unit currently recording sunshine at the South Pole:

https://flickr.com/photos/jamfan2/8229074686/in/set-72157632128663488/lightbox/

2012-11-25
Touring the Bicep2 Microwave Telescope with Physicist Jonathan Kaufman

South Pole is home to many, many world-class science experiments, laboratories, and telescopes. One such telescope is the Bicep2 Microwave Telescope. On the ice this year working on the hardware and software is Physicist Jonathan Kaufman. Yesterday, Jon was nice enough to give me a quick tour of the telescope and lab, as well as an opportunity to see them send the liquid helium dewier off to the Cryogenics Lab for a refill. Here’s video of Jon giving a tour, and photos of the dewier.

About Bicep2, from Caltech:

The primary goal of BICEP2 is to measure the polarization of the cosmic microwave background (CMB). The CMB is a nearly perfect, uniform black body at 2.7 K, with degree-scale temperature anisotropy of about 0.1 mK and polarization on the order of microkelvin. This radiation was emitted 380,000 years after the Big Bang, at the time of recombination, when the Universe first became transparent to light. The temperature anisotropy and polarization of the CMB are some of the most powerful ways of understanding the early Universe. Cosmologists believe the Universe experienced a rapid period of cosmic inflation during its first fraction of a second, exponentially expanding from a dense, hot subatomic volume. Many models of inflation predict that this rapid acceleration would have generated gravitational waves that would remain energetic enough 380,000 years later to leave an imprint on the CMB. BICEP2 is searching for this imprint by measuring the pure-curl component of the CMB polarization on degree angular scales, which is largely free of contamination from sources other than primordial gravitational waves.

More on Bicep, Bicep2, and Keck from Christopher Sheehy. (PDF Link)

Snowmobiling out to the Bicep2 Telescope’s Lab, which also shares space with the South Pole Telescope.

Liquid Helium dewier, and Jon

Looking off the roof of the Bicep2 across to the SPT

Lowering the dewier
https://www.flickr.com/photos/jamfan2/8205021288/lightbox/

Bicep2

2012-11-23
My First Sundog

This past week, while I was hanging out with Utility Technician Charles “Chuckles” Letourneau, I saw my first Antarctic Sundog, or “Parhelion”.

A quick description of this spectacularly beautiful atmospheric phenomenon from Wikipedia:

Sundogs are made commonly of plate-shaped hexagonal ice crystals in high and cold cirrus clouds or, during very cold weather, by ice crystals called diamond dust drifting in the air at low levels. These crystals act as prisms, bending the light rays passing through them with a minimum deflection of 22°. If the crystals are randomly oriented, a complete ring around the sun is seen — a halo. But often, as the crystals sink through the air they become vertically aligned, so sunlight is refracted horizontally — in this case, sundogs are seen.

As the sun rises higher, the rays passing through the crystals are increasingly skewed from the horizontal plane. Their angle of deviation increases and the sundogs move further from the sun.[4] However, they always stay at the same elevation as the sun.

Sundogs are red-colored at the side nearest the sun. Farther out the colors grade through oranges to blue. However, the colors overlap considerably and so are muted, never pure or saturated. The colors of the sundog finally merge into the white of the parhelic circle (if the latter is visible).

It is theoretically possible to predict the forms of sundogs as would be seen on other planets and moons. Mars might have sundogs formed by both water-ice and CO2-ice. On the giant gas planets — Jupiter, Saturn, Uranus and Neptune — other crystals form the clouds of ammonia, methane, and other substances that can produce halos with four or more sundogs.[5]

2012-11-22
Launching a Meteorological Balloon with South Pole Meteorologist Phillip Marzette

The weather here at the South Pole is intense – one day it’s crazy storms, the next day it’s sunny and nice – and it’s always cold. Detailed weather observation and reporting happens daily here, and the man in charge of it all is Meterologist Phillip Marzette.

The other day, Phil let me tag along and help him launch a weather balloon carrying Radiosonde 15 miles into the atmosphere. During its flight, the Radiosonde took continuous atmospheric and position measurements, and relayed them to us on the ground. Here’s the video of the setup and launch procedure.

2012-11-21
Taking Ozone Measurements at the South Pole Atmospheric Research Observatory

Today, Atmospheric Scientist Kelliann Bliss shows us how she takes ozone readings at the South Pole Atmospheric Research Observatory (ARO).

A bit more on ARO, from NOAA:

The Atmospheric Research Observatory (ARO) at the Amundsen-Scott South Pole Station is a National Science Foundation facility used in support of scientific research related to atmospheric phenomena. ARO is located approximately five hundred meters grid east-northeast of the main station, physically separated and generally upwind of all other station facilities.

2012-11-20
Playing With Liquid Helium At The South Pole Cryogenics Lab

To support the various telescopes and experiments here at the south pole, a ton of resources are necessary – power, heating, environmental protection, and somewhat counterintuitively, cooling. Some of the telescopes here are so sensitive, and looking at such distant signals, that in order to work properly they need to be cryogenically cooled down to just above absolute zero. The only practical way to do this is with a complex refrigerator that uses liquid helium, which sits at 4 degrees kelvin in its natural state.

Liquid helium is a dangerous, volatile, expensive substance, and in order to be able to supply the experiments with an adequate amount of it, there’s an entire cryogenics laboratory right next to the main station.

The other day Engineer and Cryogenics Technician Flint Hamblin gave me a quick tour of the lab. A few pics:

The Cryo Barn, as it’s called, is a black structure, with huge insulated loading doors. It’s about a 10 minute walk from the station.
https://flickr.com/photos/jamfan2/8201601328/in/set-72157632052373951/lightbox/

Inside, there’s a ton of equipment surrounding huge liquid helium holding tanks. These tanks are vacuum insulated to prevent the liquid helium from boiling, and to protect people working around the tanks from being injured by the extreme cold temperature.

In order to get liquid helium over to the telescope (namely Bicep2), it must be carried in a specially designed “dewier” – a large vacuum flask. Flint transports liquid helium dewiers on the ice with a snowmobile.

2012-11-17
Exploring the Ice Cube Neutrino Observatory

One of the amazing benefits of living here at the South Pole is that I get access to some of the world’s leading scientists, and the experiments they’re working on. In fact, the luxury of having meals and chatting with scientists, and then being able to go out to their experiments is by far one of the absolute best things about living here. It’s truly a once in a lifetime opportunity to have this many amazing people living together in one building. Once such experiments is the Ice Cube Neutrino Observatory. Photos.

After making friends with a few of the scientists working on the Askaryan Radio Array (ARA) project coupled with the Ice Cube Lab, I was invited out to the main lab building to check out the facility, as well as help the ARA project set up their workshop.

First, a bit of background on Ice Cube:

IceCube is a particle detector at the South Pole that records the interactions of a nearly massless sub-atomic particle called the neutrino. IceCube searches for neutrinos from the most violent astrophysical sources: events like exploding stars, gamma ray bursts, and cataclysmic phenomena involving black holes and neutron stars. The IceCube telescope is a powerful tool to search for dark matter, and could reveal the new physical processes associated with the enigmatic origin of the highest energy particles in nature. In addition, exploring the background of neutrinos produced in the atmosphere, IceCube studies the neutrinos themselves; their energies far exceed those produced by accelerator beams. IceCube is the world’s largest neutrino detector, encompassing a cubic kilometer of ice.

– From Wisc.edu

Ice Cube Diagram:

And on the Askaryan Radio Array (ARA) from Wisc.edu:

Building on the expertise gained in these efforts, and the infrastructure developed in the construction of the IceCube optical Cherenkov observatory, we are developing an array, known as ARA (The Askaryan Radio Array), and installing it in the deep ice near the geographical South Pole. South Polar ice is, in fact, perhaps the most extensively-studied on the planet, the combination of ice thickness and favorable radiofrequency dielectric characteristics, as well as the excellent scientific infrastructure and the co-location of the IceCube Observatory, makes that site unparalleled for this study. With a fiducial area of an unprecedented 80 km$^2$, ARA’s size was chosen to ensure the detection of the flux of neutrinos “guaranteed” by the observation of the GZK cutoff by HiRes and the Pierre Auger Observatory. Within 3 years of commencing operation, the full ARA will exceed the sensitivity of any other instrument in the 0.1-10 EeV energy range by an order of magnitude. Because the antennas will be deployed in boreholes extending below the firn layer to 200 m depth, it will have the ability to distinguish surface noise from sources originating in the ice cap, otherwise not possible in the ballon borne approach employed by ANITA. Even under the extreme assumption that UHE cosmic rays are pure iron, ARA will have sufficient sensitivity to establish the presence or absence of the secondary UHE neutrinos produced by the interaction of cosmic rays with the cosmic microwave background. Such an observatory would also provide an unique probe of long baseline high energy neutrino interactions unattainable with any man-made neutrino beam.

Visiting the lab,and helping out with both setup of the worksite, as well as observing the installation of new networking hardware was great. A few pics:

Our transport from the station to Ice Cube Lab was in a van, but not any ordinary van

Our transport from the station to Ice Cube Lab was in a van, but not any ordinary van

The Ice Cube Lab

Beginning to setup the shop tent. The sun in Antarctica is intens, as is the cold and wind. All skin must be covered.

The main control center for the Ice Cube Observatory

The main control center for the Ice Cube Observatory

This is where raw data from each photomultiplier tube frozen in the ice comes into the racks of electronics.

The main control center for the Ice Cube Observatory

This is where raw data from each photomultiplier tube frozen in the ice comes into the racks of electronics.

Looking out across the way is the MAPO building, housing the South Pole Telescope and Bicep2. More on those later.

2012-11-16
Learning About Space Suit Design With Astronaut Joseph Tanner
This past week, my brother Jason and I were fortunate enough to be allowed to sit in on a guest lecture at the University of Colorado Engineering Center by NASA Astronaut Joe Tanner. Joe spoke to us about the ins and outs of spacesuit design, and shared a bunch of his personal stories. A pic or two, as well as my brief notes:

Space Habitat Design – ASEN 5158

Notes
- Main challenges of EMU – refurbishment of the suit after every flight.
- Now on ISS, suits left on station for a long time – like 6 months. modular components
- EMU – on extended EVA’s, it’s necessary to resupply suit halfway through – takes 5 minutes minutes to refil o2.
- Limiting consumable on EMU is the co2 scrubbing system
- After Ed White’s gemini EVA, training focus was switched to underwater training
- Apollo EVAs
  - Umbilical based
  - to pick up film from outside of module
  - no cooling system
  - Backpack – SOP – Secondary o2 pack
- Apollo Lunar walk SOP
  - Very high center of gravity because of high location of SOP
- STS
  - SAFER – cold gas jet mechanism for navigating in space.
- Suited Environments
  - Launch, Entry and Abort – must be able to operate flight controls, as well as emergency depress/egress
  - Orbital – shirts and shorts, unless on TV, then nasa wants the astronauts to wear long pants.
  - Lunar/Mars – main concern is the dust – will eat the suit alive!
  - NEO’s – Biggest problem is body stabilization
- Suit Functional Requirements
  - Environmental control and live support parameters
    
    Maintain Pressure
    
    Remove co2
    
    Provide o2
    
    thermal control
    
    humidity control
    
    trace contaminant control
    
    mmod/radiation protection
    
    food/water
    
    water is space suit is tube with actual bite valve from Camelbak
    
    waste
    
    mobility/dexterity
- ORLAN Russian Spacesuit
  - In use for 40+ years, still in use today. Pressurized at 5.7 psi suit, which makes an easier transition from cabin to eva, but makes hand dexterity more difficult.
- Delta p Concerns
  - Getting from cabin pressure to suit pressure – issues include decompression sickness, bends, etc
  - Prevented by lowering cabin pressure, lowering N2 content in atmosphere, or lowering n2 content in human.
  - Prebreathe protocol – facilitate equilibrium
  - Zero prebreathe is at 8.3 psi
- Haldane’s Ratio – Defines cabin/suit pressure ration based on risk of DCS
2012-11-05
Video: Hurricane Sandy – A View From Above

The New York Times posted this incredible timelapse video of Hurricane Sandy’s roll through NYC. Incredible footage..

Watching the hurricane from the 51st floor of the New York Times building.

2012-10-30
Infographic: XKCD’s A History Of The United States Congress

Great big infographic from favourite cartoonist Randal Munroe of XKCD. A look at american politics over the years..

2012-10-28
Video: Paramotor Sky Racers

Paramotor Sky Racers – Parabatix – YouTube.

2012-10-23
Google’s Influence on Photography – Street View and Beyond

Following up on yesterday’s post on Google Street View in the Grand Canyon, here’s a great article from LightBox. It goes over the incredible impact of Google’s Street View experiement, and what it’s done for mapping and photography. From the article:

In the catalogue to the show Exposed: Voyeurism, Surveillance, and the Camera since 1870, editor and curator Sandra Phillips compared the biblical story about elders spying on Susannah to present day, saying: “Today, however they would use cell phones to grab a picture of a young woman in a compromised position and send it to friends, having located her garden through Google Earth. Human hunger for seeing the forbidden has not changed. The technologies to facilitate it have.”

And she’s right—this technology has been adapted quickly by artists and devoured by the art world. Doug Rickard used Google Street View to see the back roads of the nation in a series called A New American Picture, which was featured at New York City’s MoMA last year and is currently on view at Yossi Milo Gallery. Geoff Dyer wrote extensively in the Guardian about Rickard, saying: “Any doubts as to the artistic – rather than ethical or conceptual – merits of this new way of working were definitively settled by Rickard’s pictures. It was William Eggleston who coined the phrase “photographing democratically” but Rickard has used Google’s indiscriminate omniscience to radically extend this enterprise – technologically, politically and aesthetically.”

Street View and Beyond: Google’s Influence on Photography – LightBox.

2012-10-21
Google Street View in the Grand Canyon: Google Trekker

Introducing Google Trekker in the Grand Canyon – what a great use of Google’s street view tech:

Today, demonstrating the rocky and rugged paths we’ll travel to make Google Maps even more complete, we’re collecting imagery from a place no car, trike or snowmobile has ever been before. On its first official outing, the Street View team is using the Trekker—a wearable backpack with a camera system on top—to traverse the Grand Canyon and capture 360-degree images of one of the most breathtaking natural landscapes on the planet.

Google Takes Its Backpack-Sized Trekker Street View Cameras To The Grand Canyon | TechCrunch.

2012-10-20
My New Favorite Shopping Site: The Wirecutter

No researching, no clicking all over the web collecing opinions – just The Wirecutter. This is by far my favorite new tech review site, because it doesn’t give options. You want the best bluetooth speaker? Here you go. It’s this one, not any others. Job, done. The Wirecutter.

2012-10-18
Everything You Need to Know About Kitchen Knives

Need a new kitchen knife? Here’s everything you need to know. I love these all inclusive guides, because they give me the tools to make a solid, informed decision. I try not to buy a lot of stuff, but when I do buy something, I like to know exactly what I’m getting, and make sure it’s the best. So, here you go, knives.

Everything You Need to Know About Kitchen Knives.

2012-10-17
The iPhone 5 Is the Best Smartphone | The Wirecutter

Good blurb from Brian Lam at The Wirecutter on the logic of upgrading your phone when the current one is “fine”. It’s “The One Thing That’s Always Within Arms Reach”, and has such an increasingly large effect on our lives that it’s the one thing worth shelling out to keep upgraded. I’m in complete agreement.

Should I get an iPhone 5 if I have an iPhone 4s or 4?

I am really against buying new gadgets when they’re not needed. But when it comes to smartphones, I think you should consider keeping up with the best. Here I will quote myself (am I allowed to do that; doing it anyhow):

Unlike other gadgets, I think you should get the best one you can and upgrade whenever you want. Go buck wild.

For me, that’s about every year…. Why? Because the smartphone is the gadget that can do anything, anywhere, any time. And its hard to think you won’t get a lot of utility and use out of the latest and greatest when it something you use that often. Also, a new handset is just an fraction of what you’re really paying for–your cellphone plan. The cost of a new handset is a few hundred dollars; the network, a few thousand over a few years. That’s pretty simple math.

I’d say a good rule of thumb is never pay more than two-thirds of a phone’s value in early termination or early upgrade fees.

via The iPhone 5 Is the Best Smartphone | The Wirecutter.

2012-10-16
Polar Infographic: Who Owns Antarctica?

Great Antarctic infographic for today – who owns that giant continent, anyway?

Courtesy of GOOD

2012-10-03
Apple reveals Lightning to microUSB adapter

Finally, and as expected, Apple is out with it’s micro USB to Lightning adapter. This adapter is necessary to satisfy Europe’s demand for all smartphones to have a standard Micro USB connection, which I certainly support. Stateside, I think it’s also the go-to adapter to carry around – as the legacy 30-pin iPod cable begins to dissapear, I think that the predominant standard charging cable will be Micro USB – so keep one of these adapters handy and never be without power.

Apple reveals Lightning to microUSB adapter to pacify Europe – SlashGear.

2012-09-28
Infographic: The True Cost of Owning an iPhone 5

Thanks to snazzily-named internet marketing firm Avalaunch for this handy infographic breaking down the ownership cost of an iPhone5…

Avalaunch via Gizmodo

2012-09-22
Explainer Video: The Story of the First Ultra Modern Phone Cable Ship – AT&T Archives

Great explainer video from AT&T, going over the first phone cable ship. Interesting!

2012-09-20
How To Generate Your Own Apple iOS 6 Passbook Passes

With Apple’s iOS6 launching today, there are a ton of new features people are exploring. One of my favorite new apps on iOS 6 is Passbook. Although Apple didn’t incorporate NFC capability into the new iPhone 5, I really don’t think it matters too much just now – thanks to Passbook.

Passbook lets users manage their frequent flyer cards, club card, store cards, and I’m sure their credit cards and metro cards soon enough. Cards are communicated to merchants via scannable barcode – 1d or 2d which is displayed on the phone’s screen.

To generate Passbook passes, it’s a relatively straightforward process. While most people will experience Passes in Passbook pushed from apps and sent in emails from airlines and the like, It’s actually possible to generate your own passes, using the new .pkpass mime type. Simply create a zip files with a few specific documents in it, and reference it with the new .pkpass mime type in a webpage or email, and boom, you’ve got a Passbook Pass!

Here’s the files, as reported on GeeksWithBlogs.net:

Passbook Pass Zip File Requirements
icon.png
icon@2x.png
logo.png
logo@2x.png
manifest.json
pass.json
singature

Too much to handle on your own? No problem, there’s naturally a generator for it. Head on over to iPass.PK and start whipping them up on your own.

Like this blog post? SHARE it with your friends via Passbook! Just load up this blog post’s Passbook Pass, and show it to a friend with a QR Code reader app.

2012-09-19
Go To The Moon With The Apollo Astronauts in Documentary “For All Mankind”

For All Mankind is a simply stunning documentary covering the Apollo missions to the Moon. Stunning on all fronts. Scored by Brian Eno. Enough said.

This movie documents the Apollo missions perhaps the most definitively of any movie under two hours. Al Reinert watched all the footage shot during the missions–over 6,000,000 feet of it, and picked out the best. Instead of being a newsy, fact-filled documentary. Reinart focuses on the human aspects of the space flights. The only voices heard in the film are the voices of the astronauts and mission control. Reinart uses the astronaunts’ own words from interviews and from the mission footage. The score by Brian Eno underscores the strangeness, wonder, and and beauty of the astronauts’ experiences–experiences which they were privileged to have for a first time “for all mankind.”-Scott B. Fisher

2012-09-13