The T962/Argoneut Experiment at FNAL

Bartoszek Engineering worked with Bonnie Fleming of Yale University on the T962/Argoneut experiment. BE's role was primarily to design the double wall cryostat and support structure. FNAL engineering did the cryogenics. The cryostat was fabricated by PHPK in Ohio.

Argoneut is a liquid argon Time Projection Chamber (TPC). It is filled with pure liquid argon that is continuously purified so that any electrons that are knocked off an argon atom by a passing neutrino are not immediately reabsorbed. The electrons drift under the influence of a high voltage electric field until they are collected on wires in several wire planes. The signals from the wires are reconstructed into a 3D image of the tracks of the particles that passed through the detector. Argoneut is the first liquid argon TPC in a neutrino beam in the US.

The pictures below show the sequence from design, fabrication at PHPK, delivery to FNAL, commissioning at the Proton Assembly Building (PAB) at Fermilab, and finally pictures in the NuMI tunnel. Argoneut was installed in the same space originally occupied by another small experiment called PEANUT. After Argoneut was installed, the Minerva experiment was installed upstream of it. (It became very hard to get good pictures once Argoneut was sandwiched between two large structures.)

Click on any of the thumbnails to get an enlarged view. You are welcome to download any of the images. If they are used for other than private viewing, credit to the Argoneut collaboration and Bartoszek Engineering would be appreciated.

The design of the cryostat

These pictures show cutaway views of the cryostat. The detector shown is a conceptual design, not the actual design of the installed TPC. The light blue solid that fills the cryostat is the liquid argon volume.

The inner cryostat flanges are sealed by Helicoflex seals. On the inner vessel, there are two Helicoflex seals on each flange so that they can be differentially pumped between the o-rings. The small hatch on the side of the vessel was designed so that the high voltage connection could be made at the cathode inside the vessel. The small white cylinder represents a purity monitor. The fill tube wraps around the inside of the vessel and goes to the bottom. The last picture shows a concept for a lifting fixture to attach the inner cryostat's end flange.

The early tunnel layouts

The big green structure in these pictures is the NuMI near detector magnet. Argoneut sits right in front of the NuMI magnet and can use the NuMI near detector as a muon range stack. Neutrinos are coming from the left in these pictures. They pass through the Argoneut detector first, then on to the NuMI detector.

Cryostat Fabrication at PHPK

PHPK did an excellent job on the fabrication of this cryostat. BE highly recommends them for cryostat design and fabrication. More information about them can be found at: PHPK Technologies.

Delivery to Fermilab Receiving

The cryostat as it arrived at FNAL.

Commissioning at PAB

Cary Kendziora's group at PAB did the assembly and commissioning of the detector and cryogenic system.

PEANUT in the NuMI tunnel

This is what PEANUT looked like before it was removed and Argoneut was installed.

Argoneut in the tunnel

These pictures show the detector installed in the NuMI tunnel. The last picture is a view looking upstream, away from the Argoneut detector. This is where the neutrino beam enters the hall.

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