Cut-away rendering of the shallow underground laboratory.
Photograph of the Electrochemical Purification Laboratory that was specifically designed to produce radiopure copper.
Copper electrodeposited from a large bath. On the left is a complete electroplate while on the right is a closeup of the bottom.
Photograph of the CASCADES shield and bottom cryostat (copper).
Comparison of background spectra from the center crystal of the CASCADES array for several different locations. From top to bottom, the traces correspond to room background measured (i) above ground, (ii) below ground, (iii) below ground inside the shield, and (iv) below ground inside the shield with muon veto activated.
Photograph of the ULBPC in a copper holder.
Pulse-height spectrum from an ULBPC showing 3H and 14C activity in a landfill biofuel methane reference gas. Also shown is a 21-day background scaled to the approximately 7-day measurement time of the sample. The vertical lines indicate the end-point energies of 3H and 14C beta decay, respectively.
Photograph of the ultra-low-background counting system that features the capacity for 12 ULBPCs surrounded by inner copper and outer lead shielding, complete with radon enclosure and muon veto. On the left is a 12-channel data acquisition system.
Comparison of the summed backgrounds above and below ground, as measured by all five veto panels of the ultra-low-background counting system.
Plots for the relative (to surface) muon intensity as a function of the laboratory overburden. The traces denote the effective depth estimate resulting from two cosmic-ray models. The horizontal line denotes an 85% reduction in observed muon events consistent with observations in the shallow underground laboratory.
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