Bartoszek Engineering was asked by Eric Zimmerman of the University of Colorado at Boulder to participate in the design and assembly of the second horn of a three horn system for the T2K experiment being mounted in Tokai, Japan. Horn 2 would be built in Boulder and shipped to Tokai to be installed in the T2K Target hall at the J-PARC accelerator at Tokai. BE was also asked by Atsuko Ichikawa of the KEK Laboratory in Japan to help with the designs of horns 1 and 3 as well. The lessons BE learned on MiniBooNE would be put to the test as these horns were both smaller and larger than the MiniBooNE horn, but the current was much higher. The T2K horns operate at 325,000 amps, instead of the 170,000 amps of MiniBooNE. Joule heating is much higher in these horns, and the radiation heating is much higher as well because the intensity of the accelerator at J-PARC is much higher.

The target hall complex at J-PARC is one of the most impressive target halls I've ever been in. The Japanese are extremely concerned about irradiating ground water and I have never seen so much concrete shielding around a beam line than there. When proton beams pass through air, as in typical target halls, the air produces a number of radioactive contaminants. To mitigate this phenomena, the T2K horns are inside a vessel that can be completely evacuated and then back filled with helium. This eliminates the heavier nuclei in air that produce such nasties as radiaoactive beryllium.

You are welcome to download any of the images. If they are used for other than private viewing, credit to the T2K collaboration and Bartoszek Engineering would be appreciated.