# Presentation: 706206

## Cost for Large Liquid Scintillator Detector

**Ken Heller**
**University of Minnesota**

** ****Active Detector – Liquid Scintillator**
** ****Target Material - Water**
** ****Read Out – Wavelength Shifting Fiber**
** ****Photodetector – Image Intensifier + ccd camera**
** ****Structure – PVC Extrusions**

**Detector cost - $1M/kTon**

## Design for Costing – PVC Structure

**15 cm**

**512 cells/plane**
**8000 cells/kTon**

## Design for Costing – Wavelength Shifting Fiber

**20 m**

**3.8 cm**

**22 m WLS fiber/scintillator cell**
**0.5 mm diameter fiber**
**	****6 m attenuation length**

**Light trapped as r**
**Fiber cost as r****2**

**U gives**** **
**2 x light of single fiber near photodetector**
**4 x light of single fiber at far end**

**0.5 mm U fiber gives**
**2 x light of a single 1mm fiber (far end) at 1⁄2 the cost**

**End sealed in extrusion process**

**Open end**

## Budget

**Scintillator – **
**	****Fluor in mineral oil concentrate**
**	****mix at site with**
**	****Mineral oil to dilute to B517L**
**	****$1.65M/kTon of scintillator**
**	****16 Tons scintillator/plane **
**	****$26.4k/plane ****=**** ****$66/m****2**
**	****Scintillator is 1⁄4 of detector mass**
**$412k/kTon detector**

**WLS Fiber 0.5mm – **
**	****$0.75/m**
**	**** ****44 m/fiber**
**	****512 fibers/plane**
**	****$17k/plane**** ****= ****$42.5/m****2**
**	****8000 fibers/kTon**
**$264k/kTon detector**

**PVC extrusions – **
**	****$1.07/lb**
**	****392 lbs/module**
**	****16 modules/plane**
**	****$6.7k/plane ****=**** ****$16.8/m****2**
**	****15.6 planes/kTon**
**$105k/kTon detector**** **
**+ ****one time die cost $200k**

**Manifolds – **
**	****$200/module**
**	****16 modules/plane**
**	****$3.2k/plane ****=**** ****$8/m****2**
**	****15.6 planes/kTon**
**$50k/kTon detector**

## Other Costs

**Photodetector IIT (2 cm x 1.5 cm)**
**	****$2500 each including CCD camera and optics**
**	****1 IIT per plane (1024 fiber ends) 2/3 IIT area**
**	****$2.5k/plane**** = ****$6.25/m****2**
**	****15.6 planes/kTon**
**$39k/kTon**

**Installation**
**	****Transport and stack light-weight modules (392 lbs)**
**	****Fill on site**
**	****64 man hours/plane - ****$1.6k/plane**** = ****$4/m****2**
**	****15.6 planes/kTon**
**$25k/kTon**

**Clear Fiber (4 modules on 4 planes to IIT)**
**	****4 m clear fiber/wls end x 1024 wls ends = 4096 m**
**	****$0.75/m **
**	****$3.1k/plane**** = ****$7.68/m****2**
**	****15.6 planes/kTon**
**$48k/kTon**

## A Self Supporting Structure

**Modules at alternating at 45****o**

**Sealed bottoms**

## Cost Summary

**Scintillator**

**WLS Fiber**

**PVC extrusions**

**Photodetector + electronics**

**Clear Fiber**

**Installation**

**Total**

**Not included: DAQ, trigger electronics, water, fiber coupling to IIT, QA, cosmic ray shield, calibration, pumps, hoists, site, power, safety, heating, cooling**

**A 20kTon liquid scintillator detector costs $20M + site + outfitting**

**Can build with current technology at reasonable price**

**Manifolds**

## Liquid vs Solid for 20kt with water absorber

| ($M) | Solid | Liquid |
| --- | --- | --- |
| Scintillator | 15.8 | 8.2 |
| Container/module | 11.2 | 2.1 |
| Small  parts | Above | 1.0 |
| WLS fiber | 6.0 | 5.2 |
| IIT + housing + cable  | 2.9 | 2.1 |
| Absorber | 2.1 | above |
| Installation | 1.0 | 0.5 |
| $/Area (m^2) |  | 154 |
| Total (20 kTons) | 39.0 | 19.1 |

**Added flexibility of liquid scintillator design**
**	****Change fraction or nature of absorber **