This is apparently the facility they are at:
JUNE 2021: TUCSON, AZ: "A spokesman with the U.S. Border Patrol Tucson Sector said it has processed approximately 2,000 children at its new soft-sided facility since it opened on April 30, 2021. The 80,000 square foot facility is located near the Tucson airport at 4550 East Los Reales Road. Border Patrol’s Tucson Sector could not give us exact numbers but said it had processed roughly 2,000 unaccompanied minors since opening on April 30, 2021.
A spokesman for the Tucson Sector said so far, the facility has only been used to process non-citizen unaccompanied children. He said the children are transferred to the custody of the U.S. Department of Health and Human Services within 72 hours."
https://www.kold.com/2021/06/25/kold-investigates-approximately-2000-unaccompanied-children-processed-tucsons-new-cbp-facility/