# Presentation: 821972

## ORLaND Facility Location and Shape

- Yu. Efremenko
- University of Tennessee

## Neutrino Bunker Should be Located Underground !!!

**Avoid Conflict with SNS mission**
**	****	*****(Get out of the way or die)***
**Reduce muon flux to the acceptable level**
***	******	******(30 meters overburden of water equivalent)***
**Absorb High Energy Neutrons**
***	******	******(Extra 3 meters of steel beyond SNS “biological” shield )***
**Eliminate Sky Shine Neutrons**
**	****	*****(Need accurate calculations of neutron propagation)***

## Detector Inefficiency for oscillation search

**Detector Inefficiency for oscillation search**

****

**r = 2m**

**t = 0.5msec**

**No less then 30 m. of W.E. is required**

## Neutrons from SNS

## Bunker Location

** ****Underground**
** ****As close rs reasonably achievable to the target to intercept large flux of DAR (Decay At Rest) neutrinos**
** ****At a place where potential for DIF (Decay In Flight) experiments exists**
** ****Capability to build access shaft/tunnel (!)**

## Linac Storage Ring  Spallation Target

**Linac ********Storage Ring ******** Spallation Target**

- H+

- 295 nsec          600 nsec

- H- 1 GeV

**Strip foil**

- H0

- Storage of
- 1160 turns

- p

- 21014 protons per pulse to the spallation target

**Linac**

**Storage ring**

**Target**

- ~ 1msec	          15 msec

**current**

**Beams time structure**

## SNS Targets

**LINAC dump**

**Strip foil dump**

**Accumulator Ring dump**

**Main Target designed to hold 2 MW of power.**
**Beam dumps – 0.2 MW**

**Proposed ORLaND**
**location**

## Analysis of the Existing Beam Dumps

| Dump | Power | Operation | DAR | DIF | Time Structure | Room to build DIF |
| --- | --- | --- | --- | --- | --- | --- |
| Main target | 2 MW | All time | Yes | Very little | Fine | No |
| LINAC dump | <0.2 MW | During tuning | Yes | Some | Coarse | Yes |
| Strip foil dump | <0.2 MW | All time | YES | Some | Coarse | Yes |
| Accumulator ring dump | <0.2 MW | During tuning | YES | Some | Fine | No |
| Beam line for the second target | ~0.4 MW | All time | YES | Some | Fine | Yes |

**No big advantage to use any given dump**

## Neutrino Spectra from the SNS Main Target

**Time**

**Energy**

## North or South Side ?

**From all points of view, a neutrino facility on the south side of the target building is more attractive than on the north side.  It gives:**
***Larger arm for the oscillations measurement from the second target station.***
***Better chance to use accumulator beam dump as a DIF facility***
***Easy to build access tunnel***
***Fewer logistics problems during construction***
**Unfortunately (for us) the SNS is going ahead with construction of long baseline neutron instruments on the south side, before we will have the opportunity for neutrino bunker construction**

## Neutrino Bunker Location

**Several different locations for neutrino bunker considered: suc under the main target building, at 0****0****, at 90****0****  and far away.**
**We conclude that the most realistic location is at 90 degrees on the north side of the target building.**
***Intercepts largest possible flux of DAR neutrinos produced by beam with fine time structure.***
***Different distances to the first and second target stations***
***Allows some room later to build dedicated DIF beam during construction of a second target station***

## Bunker Construction I

**Bunker Construction I**

**Propose to use slurry wall technique**
**Minimizes impact on the SNS target building**
** ****Allows building bunker at closest possible proximity to the target building**
**It is very well developed technique, widely use to build skyscrapers foundation in the big cites (“Big Dig” in Boston)**

- Build guide wall

- Excavate and fill trench with slurry

- Lover wall panels

- Replace slurry with concrete

## Bunker Construction II

**Build even sectors****	****       Finish all sectors****	****        Excavate inside**

## Bunker Shape

**2.7 kft****2**** = $20.3M**

**3.8 kft****2**** = $14.5M**

**Out of three general bunker shapes circular one has a better ratio volume/price.**
**It uses less concrete, require less excavation, and more straightforward to build. **
**Engineering studies at early stage indicated that for similar volume, square bunker is ~80% more expensive than a circular one**