The TolTEC Camera

This page will be a lot more interesting to astronomers once we're posting TolTEC images. For now you'll have to be content with instrumentation developments and cheery team members at meetings.

The Final Pre-Shipment Setup at UMass

Here are a set of images of the TolTEC setup as we prepare our final cooldown prior to shipping to the LMT. Click any image to explore.

Image description — The setup for our new flexible thermal straps for the 0.1K connection to the dilution refrigerator.

Image description — Here's another view of that connection. The 1K thermal connection is directly above our 0.1K connection. This is tight and delicate assembly work.

Image description — Copper tape provides a light barrier between the 1K enclosure that suspends the array and the hot (4K) outside of the array mounts.

Image description — The back of our brand new 1.4mm array. The stainless steel coaxial cables at the bottom bring the probe signals in and the astronomical signals out. 12dB attenuators help to thermalize the input signals at 1K.

Image description — The 1.4mm feedhorn array during a fit-test. There are approximately 1300 feedhorns.

Image description — Another view of the feedhorn array during a fit-test. The blackened ring arround the array absorbs stray light.

Image description — Reid Contente installing the 1.1mm array on our optics bench. We are also fit-testing a new lyot stop baffle (to the right).

Image description — The lyot stop with it's new surrounding baffle (right) and the first dichroic splitter (left). This is a fit-check prior to blackening the lyot stop baffle.

Image description — Steve Kuczarski carefully checking the fit.

Image description — Blackening the lyot stop baffle is dirty work. We use a combination of stycast 2850 epoxy and carbon-loaded cloth fabric that has excellent absorption properties in the infrared and millimeter wavelengths.

Image description — The baffle is pretty big so we had to build a special oven to cure the epoxy.

Image description — Nat DeNigris checking the transparency of the baffle.

Image description — Steve, Sophia Abi-saad and Nat installing components on the optics bench.

Image description — All of TolTEC's cold optics installed on the optics bench for the first time. Everything attached to the optics bench will be cooled to cryogenic temperatures.

Image description — Another view of the optics bench. Light enters through the lyot stop (upper left corner) and, depending on its frequency, finds its way to one of the three detector arrays. 1.1mm array in lower left corner near Nat, 2mm array in the center at the top, and the 1.4mm array in the right corner near Reid.

Image description — Rear view of the optics bench. The new 1.4mm array is on the right.

Image description — Disco lights illuminate Steve as he double-checks thermal connections.

Image description — Front view of the optics bench. Our 4K lyot stop is on the left and the 1.1mm detector array is on the right.

Image description — Another view of the assembled optics bench.

Image description — Rear view of the 2mm detector array showing its thermal connections to the coldest parts of the cryostat. All of the key thermal interfaces are hidden below the optics bench.

Image description — The 1.1mm detector array. In front of it is a silicon lens and a dichroic splitter.

Image description — Everything set and ready to be closed up.

Image description — Just prior to closing, a tired bunch of our team poses for one last pic. From left to right: Steve Kuczarski, Grant Wilson, Reid Contente, Zhiyuan Ma, Sophia Abi-saad, Michael McCrackan, and Nat DeNigris.

Image description — Though dabbing is technically illegal in the lab, Sophia is armed with a tagging gun so we let her do as she pleases.

Another Cooldown at UMass

After a long buildup, detectors being installed inside TolTEC at UMass Click any image to explore.

Image description — A view under the optics bench as it is being installed onto the cryostat. The gold busbars that will carry the heat from the arrays are visible, along with the wiring breakout board for the Low Noise Amplifiers. The vertical aluminum columns are supprts for the optics bench.

Image description — Another view under the optics bench. The gold plated busbars disappear out of the volume in the back, headed for the Oxford Instruments dilution refrigerator.

Image description — RF wiring from one detector network. These cables transition from 4K to 1K and carry the signals from approximately 650 detectors. They will eventually be joined by another 6 sets of cables to carry all 4006 detector signals from the 1.1mm array.

Image description — Nat is making electrical and thermal connections as the optics bench is lowered onto the cryostat.

Image description — Thermometry wires snake their way around the cryostat, giving us our only glimpse into the environment at ultra-low temperatures.

Image description — A veritable superhighway of cold.

Image description — With the opics bench now in place, Yvonne and Nat prepare the M7 mirror and complete some electrical connections. In the foreground is the 1.1mm detector array and a low noise amplifier.

Image description — The M7 mirror was built at ASU. It is the first cold optic (at 4K) inside the cryostat.

Image description — Steve is installing the thermal connections to the 1.1mm array.

Image description — The front of the 1.1mm array. No, we didn't forget to take the lens cover off. Our first tests want the detectors to be "in the dark."

Image description — Thermal straps for the 1.1mm array. The top strap is directly connected to the array and should make it to 0.1K. The bottom strap connects to intermediate mechanical supports and will cool to 1K. The round pucks are cryogenic thermometers to track the progress of the cooling.

Image description — A side view of the RF cabling coming from the 1.1mm array. The cable connector is close to the magnetic shield but as long as they are not touching we are in good shape.

Image description — The optics bench is finally installed. Let's get cold!

In the Lab at Northwestern University

Images from the Conference for Undergraduate Women in Physics in January, 2019 Click any image to explore.

Image description — Giles Novak shows off the Northwestern lab to students attending the Conference for Undergraduate Women in Physics, hosted at Northwestern in January, 2019. The half wave plate rotator is in the background.

Image description — Professor Novak showing the half wave plate rotator that Northwestern is building for the TolTEC project. This rotator will rotate the plane of polarization of the incoming light.

Image description — A great group of young physicists in training.

More UMass Cryogenics Testing

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Image description — Miranda is enjoying assembling the low thermal conductivity mechanical joints for TolTEC.

Image description — Reid and Natalie assembling the ultra-low temperature thermal bus bars inside the main cryostat. The Oxford dilution refrigerator can be seen in the background.

Image description — The assembly of this system takes a long time as all the parts are delicate and must be carefully placed. Fortunately, once we get this system tuned up it should be good for the long run and not need to be touched again until we ship to the telescope.

Image description — There's a lot going on in this picture of the inner chaber of our Auxiliary pulse tube cooler. The horizontal copper bar is the main cooling connection to the 4 Kelvin stage of the main cryostat. Thermal contraction of that bar requires us to have a flexible link between it and the pulse tube cooler's 4K head. Developing these straps for good flexibility but excellent thermal conduction was a major undergraduate project in the lab during the last year.

Image description — Another view of the flexible thermal straps on the 4K stage. There is another set of straps in the background that makes the thermal connection to the 45K stage. All the wires floating around the system are for thermometers.

Image description — The lab is a busy place during assembly. And no, we do not use scotch tape at cryogenic temperatures.

Image description — Reid taking documentary photos of the setup that we refer to during the experiment. Miranda and Steve are working on the thermal connections between the dilution fridge and the main cryostat.

Image description — Steve sewing multi-layer insulation. That guy is willing to do anything we throw at him.

Image description — Assembly of the thermal connections between the dilution fridge and the main cryostat. The gold bar is the connection to the 1K busbar.

Image description — The 1K (top) and 0.1K thermal connections between the dilution refrigerator and the main cryostat.

Image description — More thermal interfaces. Here we are looking at the snout of the dilution fridge. The outermost bolt pattern is the 45K interface. Moving inward we have the 4K and 1K interfaces. None of these links can touch when the system is running.

Image description — A photo to confirm that the 1K interface is not in danger of touching the 4K interface.

Image description — Natalie cleans up a copper shield that was a little too close for comfort.

Image description — The 4K enclosure of TolTEC is all closed up with MLI - or maybe Steve is making the world's largest batch of Jiffy Pop popcorn.

Image description — Multi-layer insulation shields the inner stage from radiation from the outer stages.

Image description — A rear view shoing the closed up "tailset" that connects the dilution fridge to the main cryostat.

Image description — The closed up tailset.

Image description — Steve and Natalie closing up the 45K chamber. Only about 2 hours to go before the system is ready to pump out.

Image description — Steve repairs a broken o-ring in place. We had never spliced o-rings before but this repair worked beautifully!

1.1 mm array pics

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Image description — Front side of the 1.1mm detector array produced at NIST. There are 4006 kinetic inductance detectors yearning to look skyward.

Image description — A closeup of the back size of the 1.1mm array showing the details of the back-etch which produces the 1/4 wavelength backshort. This allows us to maximally couple the detectors to the incoming light.

Image description — The entire back of the 1.1mm array produced at NIST.

Cryogenics in the UMass Lab (Summer 2018)

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Image description — Alan, Miranda and Steve with the new 45K enclosure

Image description — Reid getting the AuxPTC ready

Image description — Reid loves his work.

Image description — The open cryostat with the 45K enclosure base installed.

Image description — Selah installing thermometry for our first cool down of the 45K enclosure.

Image description — Selah installing thermometry for our first cool down of the 45K enclosure.

Image description — The custom flexible thermal straps installed in the AuxPTC's 45K stage.

Image description — So far so good, now to add the MLI blankets.

Image description — Cozy. The MLI reduces the radiation loading on the 45K stage.

Image description — Amy is modeling optics in the background.

Image description — The closed up main cryostat.

Image description — MLI blanket preparation by Natalie, Reid and Steve.

Image description — From left to right: Amy, Natalie and Reid.

Image description — Selah leak checks some (very) leaky feedthrus.

Image description — Selah and Natalie suit up for some chemistry in the fume hood.

Image description — They love their work too.

NIST Testing of Array Fab

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Image description — NIST is developing its ability to fab KID detectors on 6 inch diameter arrays. Here is one of their first tests - a set of 2000 resonators

Technical Kickoff Meeting

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Image description — Some members of the technical team in the lovely city of Cholula, Mexico.

Image description — Sam, Miguel and Daniel

Image description — Project Manager Steve Kuczarski leading the discussion.

Image description — TolTEC Project Manager Steve Kuczarski

Image description — Phil, Sean, Sam, and Miguel

Image description — Phil, Sean and Sam

Image description — Jay Austerman, who leads the detector development

Image description — Simon Doyle and Edgar

Image description — Miguel, Daniel, Victor and Salvador, the heart of the mm-wave lab at INAOE

Action in the INAOE mm-Lab

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Image description — Salvador working on ROACH-2 electronics for KID readouts.

Image description — Students closing up the TolTEC prototype camera system for testing.

Image description — A test KID detector array fabricated at INAOE.

Image description — Miguel Velazquez, one of the INAOE mm-lab leaders

Tour of the LMT (Sep 29, 2016)

Click any image to explore.

Image description — Approaching the LMT during the rainy season.

Image description — The LMT receiver cabin with AzTEC in the background.

Image description — One floor down in the LMT's back-end electronics room.

Image description — Jay and Sean checking out back-end electronics.

Image description — Inspecting the 1mm EHT receiver that is under wraps.

Image description

Image description — TolTEC will be mounted up high.

Image description — Some of the AzTEC coupling optics.

Image description — The LMT at night. Image Credit: James Lowenthal

Image description — The LMT at night. Image Credit: James Lowenthal

Image description — The LMT at night. Image Credit: James Lowenthal

This material is based upon work supported by the National Science Foundation Grant No. 1636621
and by the Large Millimeter Telescope Project.
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