March 19, 2010Kara Keeter1 Ultra-Sensitive Immersion Tank MOTIVATION –WHOLE-BODY COUNTING –TARGET SENSITIVITIES TO – g/g U/Th, etc. –POLLING OF ISE COLLABORATIONS MODEL: BOREXINO COUNTING TEST FACILITY –CTF USED TO MEASURE BACKGROUND LEVELS IN LS

March 19, 2010Kara Keeter2 COMPONENTS (BOREXINO CTF MODEL) –LS INNER VESSEL – 2 m diam. sphere –NYLON CONTAINMENT FOR INNER VESSEL –PMTS (~100) Light concentrators, associated electronics, calibration system –PMT SUPPORT STRUCTURE SS? –WATER SURROUNDING PMTS? (OUTER VESSEL) - 4 m diam. cylinder? SS Containment for Outer Vessel –ACCESS FROM TOP OR SIDE? Ultra-Sensitive Immersion Tank

March 19, 2010Kara Keeter3 COMPONENTS (MOST RECENT PLAN) –LIQUID SCINTILLATOR – 4 m. diam. X 4 m. high cylinder –Containment – SS? –ACCESS FROM TOP –PMTS (~100) Light guides/reflectors, associated electronics, calibration system –PMT SUPPORT STRUCTURE SS? Ultra-Sensitive Immersion Tank

March 19, 2010Kara Keeter4 CONSIDERATIONS –ACCESS FROM TOP OR SIDE Top access is easier if there is room (crane vs. rails) Nylon for container/wall? N 2 cover gas? –Geometry – inner/outer vessel, or one vessel? Locate PMTs as far from center as possible, to shield from PMT and PSUP background Borexino CTF has PMTs at 3.3 m from center (2.3 m from nylon wall) Possibly incorporate part of water shield, i.e. in corner Possibly use event reconstruction to determine events originating within fiducial volume? Ultra-Sensitive Immersion Tank

March 19, 2010Kara Keeter5 CONSIDERATIONS –WILL NEED PURIFICATION SYSTEM FOR LS IF ULTRA-PURE WATER IS USED, WILL NEED TWO SYSTEMS –WILL NEED CHILLER FOR COOLING FOR PMTS? –N 2 COVER GAS SYSTEM –RADON LEACHING? –IF THE ROOM DOESN’T HAVE AN ACTIVE MUON VETO THEN CONSIDER ONE JUST FOR IMMERSION TANK, OR PUT SOME PMTS AT BOTTOM (CTF HAS 20) Ultra-Sensitive Immersion Tank

March 19, 2010Kara Keeter6 CONSIDERATIONS –CHOICE OF LS (PC+PPO? LAB+PPO? etc.) –CHOICE AND PLACEMENT OF PMTS (~ ) LIGHT CONCENTRATORS, ASSOCIATED ELECTRONICS, CALIBRATION SYSTEM CTF OPTIMUM WAVELENGTH ~ 390 nm Ultra-Sensitive Immersion Tank

March 19, 2010Kara Keeter7 COSTS –FOR FIRST APPROXIMATION, ASSUME BOREXINO CTF AS MODEL 2-m diam. INNER VESSEL W/ LS AND NYLON CONTAINMENT –VOLUME = 4.2 m 3 = 4200 L = 1,100 gal –Unpurified: Approx. 21 $500 / barrel of LAB = $10,500 4-m diam. x 4-m high cylinder (MOST RECENT DESIGN) –Volume = 50 m 2 = 50,300 L = 13,300 gal –Approx. 240 $500 / barrel of LAB = $121,000 Ultra-Sensitive Immersion Tank

March 19, 2010Kara Keeter8 COSTS PMTS (~ ) –$50 k - $200 k, depending on choice –Light concentrators, associated electronics, calibration system –CTF: 120 PM $2800 each = $336,000 IN ULTRAPURE WATER (CTF MODEL) –Ag-coated light ~$330 each = $40,000 IN LS (MOST RECENT DESIGN) –Al-coated light $140 each = $17,000 Ultra-Sensitive Immersion Tank

March 19, 2010Kara Keeter9 COSTS –4-m diam. SS Outer Vessel w/ access port –SS PSUP –Purification plant(s) –Chiller, cover gas, etc. Ultra-Sensitive Immersion Tank

March 19, 2010Kara Keeter10 STUDIES NEEDED –CHOICE OF LS CHOICE OF PMT –INNER/OUTER VESSELS VS. ONE VESSEL –EVENT RECONSTRUCTION, FIDUCIAL AREA, PLACEMENT OF PMTS –ETC. Ultra-Sensitive Immersion Tank