1. iEFIG update Joe Lykken | iEFIG Chair ELBNF IB phone meeting | 6 March 2015

2. iEFIG critical path item: cavern layout Joe Lykken | iEFIG update | ELBNF IB phone meeting The CD-1 approval still in force is for a “10+30” kiloton design For the CD-1 refresh in July, want to present a cavern layout consistent with a modular staged approach with four 10 kt (fiducial )cryostats This will also determine what constitutes “Phase 1” for which we will seek CD-2a/CD-3a approval in November To keep on track we need to get the specs for the desired cavern layout to our A&E firm ASAP The iEFIG and the engineering team are 100% focused on this 23/6/2015

3. High-level requirements affecting cavern layout (examples) Joe Lykken | iEFIG update | ELBNF IB phone meeting Capacity to accommodate a minimum of 40 kt fiducial mass modular LArTPC Target 1 st 10 kt detector ready for detector installation on time scale of 2021 The experiment shall be implemented with identical (with minor differences) cryostats of at least 10kt fiducial volume Projects’ schedules shall reflect future continuous expansion to full detector size Ability to accommodate either single- or dual-phase LArTPC alternatives Lay-down areas shall be provided for staging detector installation, including space for clean room(s) at the entry point into the cryostat for detector installation 33/6/2015

4. High-level requirements affecting cavern layout (examples) Joe Lykken | iEFIG update | ELBNF IB phone meeting In choosing the locations of the different spaces (cryostat pit, cryogenic systems, conventional facilities infrastructure, detector systems and laydown areas) it is required that they be positioned to minimize the interference between activities in one with those in another Requirement to be able to slosh LAr from one cryostat to another during the phases: 2 nd cryostat available for Ar transfer at start of 1 st detector filling Safe access and egress shall be provided for all personnel from any location during all phases of construction, commissioning and operation in any underground space Only areas which are accessed infrequently and by specially trained personnel may be higher than ODH class 1 43/6/2015

5. High-level considerations affecting cavern layout Joe Lykken | iEFIG update | ELBNF IB phone meeting It is preferable that the caverns be within the zone explored by the geotechnical drilling program It is preferable that the caverns stay out of zone 4, which contains rhyolite dikes 53/6/2015

6. Option 5a Parallel Central Utility Space 6 The southern cavern is outside the studied area, but we believe it may be close enough. Since the CF and cryogenics are in a separate chamber, there is no conflict with cryostat & detector laydown

7. Ranking and cost/schedule summary 7 Criteria should be “weighted” based on importance. Rankings are based on the assumptions we’ve been using for layouts and phasing. Examples: Analysis to date has focused on quickest 10 kT. If the focus were on quickest 40 kT, we could approach excavation differently to make any option faster (parallel vs. serial excavation). This could change the rank of the second row. If stress distribution is more important than fitting within the geotechnical studied area, we could spread out options and change the ranking in that row.

8. Next Steps Joe Lykken | iEFIG update | ELBNF IB phone meeting iEFIG meets Monday with goal of a giving a green light to a new cavern layout (most probably something very close to Option 5a) Engineering team can develop detailed specs to deliver to A&E firm in about a week This will put us on a tight but viable trajectory for the CD-1 refresh Details to be iterated with the ELBNF collaboration as we proceed 83/6/2015