# Presentation: 351576

## New Detectors for keV to GeV Neutrino Physics, Particle Physics and Astrophysics

***New Detectors for keV to GeV Neutrino Physics, Particle Physics and Astrophysics***
***BNL Particle Physics Seminar***
***Oct 5, 2005***
**R. S. Raghavan**
**Virginia Tech**

## Neutrino Physics Program at VT

**Neutrino Physics Program at VT**
**Borexino at Gran Sasso (in construction in Italy)**
**LENS--****Advanced R&D—approaching Test Detector**
**HSD—hyper scintillation detector --****study group**** **
**Low Background Underground Test Laboratory--**
**                ****under construction in the Kimballton Mine **
- VT Nu** Group:                **   **Zheng Chang**
**                                                    ****Christian Grieb**
**                                                    ****Steve Hardy**
**                                                    ****Matt Joyce**
**                                                    ****Mark Pitt**
**                                                    ****Derek Rountree**
**                                                    ****RSR**
**                                                    ****Bruce Vogelaar**
**New Tenure Track Faculty position approved- Search Process initiated**

## LENS: 125 ton Indium Liq. Scintillation Detector

**LENS: ****125 ton Indium Liq. Scintillation Detector**
- Solar neutrinos:
**>*****10 keV signals from >~100 keV solar nu (pp,Be, CNO, pep)***
**Neutrino Luminosity of the Sun**
**Nu Physics, Particle Physics, Astrophysics**
**HSD: ~50 kT Liq. Scintillation Detector**
- Geo Neutrinos
- Supernova Relic Neutrinos
- Proton Decay
- Long Baseline Neutrino Physics
- ***MeV to GeV signals***
- **Geophysics, Nu Physics, Particle Physics, Cosmology**
*Large Scale Liquid Scint. Detectors—Technology Mature –Imaginative Applications Possible*

**Kimballton Lab?**

**Homestake**
** ****DUSEL?**

## NEUTRINO Physics-

- Non-zero Nu mass settled
- What Next ?
**Nail down new mass-mixing matrix **
**Use massive neutrino as tool for probing**
**  ****new particle interactions, symmetries**
**Probe sun deeply**
** **
- The new solar neutrino chapter:
- ---high precision data, unprecedented questions;
-                                   unique answers

## SOLAR NEUTRINOS

**Sun as ideal neutrino factory**
***Highest Flux***
***Flavor specific –electron flavor only***
***Longest baseline***
***Largest Mass***
***Low E spectrum-Several specific sources***
***Low Energies—Unique tools, largest   ***
***     ******flavor effects***
***Neutrino flux at source STANDARDIZED***
***     ******(via photon luminosity)***
-  **Best Machine –Available FREE-- for**
**New Physics of Neutrinos**
**Sun ideal Laboratory for study of**
**    ****Non-std Neutrino  phenomenology.**

## How well has  this Factory been utilized?

**Spectral Data**
**ONLY for 10****-4**** part**
**Current data only for**
**Enu > 5 MeV**
**Discovery Potential **
** ****Highest at LOW energies**
**NO SPECTRAL DATA **
** ****AT LOW ENEREGIES**
**basic pp neutrinos?**
**“****holy grail” of solar nus**
**FULL POWER OF MACHINE**
** ****NOT USED AT ALL !**

****** ****Need New Technology**
**LENS (Low Energy Neutrino Spectrometer)**
**         ****based on the Indium Target**

## LENS (Indium):  SCIENCE GOAL 

**LENS (Indium):  SCIENCE GOAL**** **
***Precision Measurement of  the***
***Neutrino Luminosity  of the Sun***
***                    ******LENS-Sol***
** ****To achieve Goal**** ******** ****Measure low energy nu spectrum (pp, Be, CNO)**
**                                     ****± ****~3% pp flux**
**                                     ****Exptl  Tool:   Tagged CC Nu Capture in ****115****In**
**           ****ν****e  ****+ ****115****In  ********  e****-**** **** +  (delay) 2 ****γ****   +  ****115****Sn**
**                              ****solar signal****            ****tag**
***                    ******LENS-Cal***
**                          ****Measure *****precise***** B(GT) of ****115****In CC reaction    **
**                                         ****using  MCi neutrino source at BAKSAN (****tagged ****ν****-                  **
**                                                   ****capture to  *****specific *****level of  ****115****Sn unlike radiochem case)                    **
**                                              *****Note:***** B(GT) = 0.17 measured via (p,n) reactions**

- R.S.Raghavan/VT/Aug05

## LENS-Sol / LENS-Cal    Collaboration

**LENS-Sol / LENS-Cal    Collaboration**
**(Russia-US:  2004---)**
***Russia:***
**INR (Mosow****):            ****I. R. Barabanov, L. Bezrukov, V. Gurentsov, E. Yanovich**
**INR (Troitsk):****        I.  V. Gavrin et al;   **
**                              ****II.  A.V.  Kopylov, I. V. Orekhov,  V. V. Petukhov,  A. E. Solomatin**
**ITEP (Moscow):        ****B. P. Kochurov, V. N. Konev,**** ****V. Kornoukhov, **
***U. S.***
**BNL:****                           ****A. Garnov, R. L. Hahn, C. Musikas,  M. Yeh**
**U. North Carolina****:     ****A. Champagne**
**ORNL:****                        ****J. Blackmon, C. Rascoe, A. Galindo-Urribari**
**Princeton U****. :            ****J. Benziger**
**Virginia Tech****:            ****Z. Chang, C. Grieb, M. Pitt, R. S. Raghavan*, R. B. Vogelaar**
**                                                             ****raghavan@vt.edu**
***NEW COLLABORATORS (US & INTERNATIONAL) ***
***CORDIALLY  WELCOME !***

- R.S.Raghavan/VT/Aug05

## LENS-Sol-In   ---Foundations    

**LENS-Sol-In   ---Foundations    **

**CC Nu Capture in ****115****In  to**
**excited isomeric level in  ****115****Sn**
**3 Unique Features:**
**Tag****:**** Delayed emission of 2 ****γ****’s**
**Threshold:**** 114 keV ******** pp  Nu **
** ****115****In abundance:****  ~96%**
**Basic Bgd  Challenge****:**
**Indium Nu target is radioactive ! **
**    ****(****τ**** =6x10****14 ****y) **
**115****In ****β****-Spect. overlaps  ****pp ****signal **
**Basic bgd discriminator:  ****Tag Energy:**
**     ****E(Nu tag) = E(****β****max****) +116 keV**
** **
***Be, CNO & LENS-Cal signals***
***not affected by Indium bgd***

- R.S.Raghavan/VT/Aug05

## Slide 10

## Tools for New Science from

** ****LENS low energy nu spectrum**
**  *****Energy dependence of Flavor survival***
**       ******** ****Physics Proof of MSW-LMA**
**       ********New Particle/Neutrino Phys Scenarios**
**  *****Appearance Effects*****  ******** New  physics**
***  ******Absolute Fluxes*****  ********Neutrino Luminosity**
**      ****Ultimate test of neutrino physics—**
**       ****Is the Neutrino  luminosity derived with **
**       ****the best   known   nu  physics CORRECT?**
**   ****The LAST & ONLY Global test—with *****photon luminosity***** which  provides absolute calibration of the sun’s energy  mechanism.  **

##          Pee (Be) / Pee (pp) < 1 ?   Pee (pep)/Pee (pp) <  1 ?

***Test of MSW LMA Physics --no proof yet !***
**                 ****no B8 d/n effect, spectral shape?) **
**          ******** ****P****ee**** (pp) = **** ****P****ee ****(vac) ******** (1- 0.5sin****2****2****θ****12**** )****? Precision value of ****θ****12**
***Non-standard Fundamental Interactions?  ***
-          ******P****ee**** (****Be) / P****ee**** (pp) < ********1 ?   ****P****ee**** ****(pep)/P****ee**** (pp) ****< ******** 1 ****?**
***Mass Varying Neutrinos? ******( ditto******)***
***CPT Invariance of Neutrinos ?***
**         ********If not LMA for ****ν****’s (contra ****ν**** ), what else? What effect?**
**                      ****Oscillations in pp spectrum? (**RSR JCAP 2003)
***RSFP/ Nu magnetic moments***** **
**           ********Time Variation of pp and Be****? ****(No Var. of ****8****B nus, no data on Lo Nu)**
-                                                                  (Chauhan et al JHEP 2005

**NEW SCIENCE—Discovery Potential of LENS**
**Massive Nu’s Open Door for probing a series of fundamental Questions**
**APS Nu Study 2004******** ****Lo Energy Solar Nu Spectrum : ****one of 3 Priorities**

**In First Two years:Focus on energy  & time dependence of P****ee****  **
**Unique answers to many basic questions without Source Calibration **

**Lo Nu**
**Only way to answer these questions !**

- R.S.Raghavan/VT/Aug05

## New Science from Relative Fluxes

## New Science from  “Appearance” Effects

##    Absolute pp, Be, pep nu fluxes at earth 

**In Five Years****   (****with source Calib****):****  **
**  ******** ****Absolute ****pp, Be, pep nu fluxes at earth**** **
**  ******** *****Measured***** ****Neutrino Luminosity (~4%)**
** ****Neutrino- Sun  Dichotomy in solar nu data**
**    ****Use Photon output of sun to standardize neutrino output  **
***Photon Luminosity ************ Neutrino Luminosity*****          **
** ***** “******External” Test of our best knowledge of the Neutrino & the  Sun***
***               ******Exptl. Status (after 6 expts/40 y) --No useful constraint***** !****   **
**                                                                                                                              **
** *****Precise L(******ν****** ) at earth************Nu parameters************Precise L(******ν******) in Sun************ L(h******ν******)?***
*********Neutrino  Physics:****** ***
***                            ************ ******Final *****Precision  Values of ****θ****12**** ,****θ****13 ****, sterile nu?**
*********Astrophysics******:******   *****L(****ν****) > L(h****ν****)****  Is the Sun getting Hotter?   **
**                                              ****L(****ν****) < L(h****ν****)**** ****Sub-dominant  non-nuclear  **
**                                                                   ****source of energy of Sun?  **
***Answers  for Big Questions****** with Small L(******ν******)≠L(h******ν******)***

**L(****ν**** inferred) / L(h****ν****) = 1.4 ****+0.2****-0.3 ****+0.7****-0.6**

- R.S.Raghavan/VT/Aug05

## Slide 16

## InLS Status (Aug ‘05 

**8% InLS (PC:PBD/MSB): **
**           ****10800  h****ν**** / MeV**

**BC505 Std**
**12000 h****ν****/MeV**

**In 8%-photo**

**Light Yield  from Compton edges**
** ****of ****137****Cs ****γ****-ray ****Spectra**

**InLS Status (Aug ‘05 **
**(VT(BL)-BNL)   Summary**
**Indium conc.  ****~8 wt%  **
**  ****(higher may be viable)**
**2.Scintillation signal efficiency**
**     ****(working value): 9000 h****ν****/MeV**
**3.Transparency at 430 nm:**
**      ****L(1/e) (working value): 10 m**
**4.Chemical and Optical **
**    ****Stabililty:  ****~ ****2 years**
**5. InLS Chemistry-- Robust**

- R.S.Raghavan/VT/Aug05

**Milestones unprecedented **
**     ****in metal LS technology**
**LS technique relevant to **
**     ****many other applications**
**Basic Bell Labs Patent**
**Filed:  2001;   awarded: 2004**

******  ****(nm)**

- Norm. Absorbance in 10 cm

**L(1/e)(PC:In 8%) ******** L (PC )**
**L(InLS) at  theoretical limit !**
**       ****ZVT39:  Abs/10cm ~0.001;       **
**  ********  ****L(1/e)(nominally) >20 m**

**InLS**

**PC Neat**

**430**

## 3D Digital Localizability of  Hit within one  cube            

**3D**** ****Digital**** ****Localizability of  Hit within one  cube****            **
** ******** ****~75mm precision vs. 600 mm (****±2****σ****) by TOF in longitudinal modules**
** ********  ****x****8**** ****less vertex vol ******** x8 less random coinc. ******** ****Big effect on  bgd**
** ********  ****Hit  localizability independent of event energy**** **
**HE ****particle (e.g. μ) ****tracks, ****γ****- shower structure directly seen****  ****      **
**                           ****SCINTILLATION CHAMBER**

**NEW  DETECTOR CONCEPT—****SCINTILLATION  LATTICE CHAMBER**

- R.S.Raghavan/VT/Aug05

## Effect of non-smooth foil assembly  on hit definition

**Effect of *****non-smooth***** foil assembly  on hit definition**
**12.5 cm cells in 4x4x4m cube;       100 keV event;  /9000 h****ν****/MeV; Signal=6x20 pe**
**Perfect optical surfaces****  :  20 pe**
**Rough optical   surfaces = ****20% chance of non- ideal optics at every reflection **
**                                              ****12 pe in vertex + ~8 pe in “halo”**

**Conclude:**
**Effect of non-smooth segmentation foils:     **
**  ****No light loss.  (All photons in hit *****and *****halo counted)**
**  ****Hit localization accuracy virtually unaffected**

## Light loss by Multiple Fresnel Reflection at intervening air gaps

## Slide 21

## Complexity of  Indium radioactivity  background

**Basic tag candidate: Shower with ****Nhit ****≥ ****3 **
**BGD tag:**** shower near vertex --chance coincident with In ****β**** in  vertex**
**                     ****One In decay:                A1  = ****β**** ****+ BS ****γ**** ****(E****tot**** = 498 keV)         ****(x1)**
**                                                               ****A2  = 498 ****γ****                                        ****(x1)**
**                       ****Two In  decays :             B   = ****β**** + BS or 498****γ**** in any combination**
**                                                                     ****from each decay                          ****(****x10****-****8****)**
**                       ****Three In  decays :           C   = 3 ****β****-decays All combinations ****(****x10****-****16****)  ****                                           **
**\                      Four In decays :              D   ****= 4 ****β****-decays** **All combinations  ****(****x10****-24****)**

**Only A1 (single decay – BS) considered  up to 2004 !**

**SIGNAL**

**Multiple In decays**
**simulate tag candidate in**
**many ways**

- R.S.Raghavan/VT/Aug05

## Nu tag template

## Indium bgd Simulations and Analysis 

**Indium bgd Simulations and Analysis**** **
**Data:  Main Simulation of Indium  Events**** **
**~4x10****6**** In decays in one cell centered in ~3m****3**** vol (2-3 days PC time)**
**  ****Analysis trials with choice of pe/MeV and cut parameters (5’ /trial) **
**Analysis-- Basics**
**Primary selection --tag candidate shower events with  Nhit ****≥ ****3**
**Every hit in the bgd shower is a possible tag vertex***** ***
**      ****in random***** *****coincidence  (10****μs) ****with a previous ****β**** ****in that cell **
**ANALYSIS STRATEGY (NEW)**
**Classify all eligible events (Nhit ****≥ ****3) according to Nhit**
**Optimize cut conditions***** ******i******ndividually****** ******for each Nhit class***
***Leads to significanly higher overall detection efficiency  ***
***     ******than with old method of same cuts for all  Nhit***

- R.S.Raghavan/VT/Aug05

##    Tag analysis must suppress bgd by ~2x104--NOT 1011

**Final Result: Overall  Bgd  suppresion >10****11**
**At the cost of signal loss by factor~1.6**

**   ********Tag analysis must suppress bgd by ~****2x10****4****--****NOT 10****11**
**   ******** ****~4x10****6****  ntuples sufficient for bgd event survivals with ~5% precision**

**Role of Experimental Tools in Bgd Suppression**
**Basic task:  Analysis of tag candidate**

- R.S.Raghavan/VT/Aug05

## For first time:

**Typical LENS-Sol: DESIGN FIGURES OF MERIT **
**Preliminary!---Work in  Progress**
**  ****InLS:**** 8% In;    L(1/e) =1000cm;     ****Y (InLS) = 9000 h****ν****/MeV;   Hits > 3pe **

**For first time:**
**Bgd problem**
** ****Solved**
**Smallest In**
** ****detector **
** ****achieved**

##    Basic feasibility of In-LENS-Sol  secure

**                                    *****Summary***
**    ****Major breakthroughs**
-    **In LS Technology**
**     ****Detector Design**
**    ****Background Analysis **
**  ******** ****Basic**** ****feasibility of In-LENS-Sol  secure**
**            ******** ****extraordinary suppression of In background**
**                   ****(all other bgd sources not critical)**
**            ******** ****Scintillation Chamber– InLS only**
**            ******** ****High det. efficiency ******** low detector Tonnage **
**            ******** ****Good S/N**
**IN  SIGHT:****   ****Simple Small LENS  ( ~10 t In /125 t InLS)**
**Next Steps—Final test:   MINILENS (2007)**
** ****Chemical Technology of large scale InLS production**
** ****Detector construction technology for Scintillation Chamber**
** ****Aim at Proposal for full scale LENS-Sol in late 2006 **

- R.S.Raghavan/VT/Aug05

## Slide 28

## Space  (10x10x10m)

**Space  (10x10x10m)**
**Adequate for**
**full scale LENS-Sol**

**Assembly **
**area**

**ROCK**

**ROCK**

**ROCK**

**Unfinished**
**Space for**
**future use**

- R.S.Raghavan/VT/Aug05

## HSD—Hyper- Scintillation Detector

**50-100 KT LIQUID SCINTILLATION DEVICE?**
**Next generation device beyond CTF, Borexino, Kamland, LENS...**
**The  technology now has a large worldwide group of experts with**
** ****experience/expertise in constructing and operating massive LS **
**detectors (upto 1 kT so far),  for *****precision***** low energy (>100 keV )**
** ****astro-particle physics**
**Essential questions for a large scale project like this:**
**  ****What science can be achieved that may be unique?**
**  ****Can one achieve multidisciplinary functionality?**
**  ****Are the possible science questions of first rank impact?**
**  ****Can it be competitive with other large scale detector **
**       ****technologies in science payoff, cost. technical readiness ...?**

## Working Group (Theory and Experiment):

**F.Feilitzsch, L. Oberauer (TU Munich0**
**R. Svoboda (LSU)**
**Y. Kamyshkov, P. Spanier (U. Tennessee)**
**J. Learned, S. Pakvasa (U. Hawaii)**
**K. Scholberg (Duke U.)**
**M. Pitt, B.Vogelaar, T. Takeuchi, M. Koike, C. Grieb, **
**     ****Lay Nam Chang, R. S. R (VT) **
**Bring together earlier work: **
**  ****Munich Group -LENA (aimed at a European site)**
**  ****R. Svoboda et al**
**  ****Y. Kamishkov et al**
**  ****RSR**
**                      **

## Slide 32

## Slide 33

## Slide 34

## Slide 35

## Slide 36

## Slide 37

## Slide 38

## Slide 39

## Slide 40

## Slide 41

## Slide 42

## Slide 43

## Slide 44

## Slide 45

## Slide 46

## Slide 47

## Slide 48

## Slide 49

## Slide 50

## Initial focus:

**Short Base line******** Lower energy 0.5-1.5 GeV anti numu**
**Minus:  lower cross section**
**             ****second maximum probably seen only**
**             ****with free protons (fermi motion)**
**Plus:    Higher flux at start (x4 than at 6 GeV)**
**            ****and at target (shorter baseline)**
**            ****than for numu at higher energies considered in VLBL planF**
**            ****---- First maximum well observable for**
**                  ****C and p targets **
**             **
**          **

## Initial conclusions for long baseline research

**Appearance Oscillation can be seen in tagged mode with **
**   ****low background**
**More work needed to see if 2****nd**** max can be **
**  ****seen sufficiently well to go beyond osc. to see **
**      ****solar interference**
**     ****CP violation**
**      ****Heirarchy effects.**
**      ****Energy close to Fermi motion limit—**
**      ****can one use C and p or only p?**
**Simulations group being formed for detailed work**
**Stay tuned!**

## Conclusions:

**HSD will be a Major Science Opportunity**
**Top notch multi-disciplinary science**
**      ****justifying cost (~300M?)**
**       ****Geophysics **
**       ****SN physics and cosmology**
**       ****Proton/nucleon decay**
**       ****Moderately long base line neutrino physics**
**#1 not possible in any other detector—Uniqueness--Discovery  **
**      ****#2 best served by low energy sensitivity--   **
**            ****higher event yields and access to**
**            ****high red shift cosmology—**
**            ****best chance for definitive landmark result**
**       ****#3 better opportunities in HSD than Cerenkov**
**           ****and at least as good handles as in LAr**
** ****#4 Preliminary considerations  positive**
**            ****Much more work needed for  firm conclusions**

## Conclusions

- New types of Detectors emerging
- for low *and* high energy particle physics
- Massive Liquid Scintillation Detectors
- ideal for a large number of outstanding
- problems
- Vigorous R&D needed to solve
- Challenging frontiers ahead in
- several “alpha Science” Problems

## ADDITIONAL SLIDES

## CPT violation !

**CPT violation !**
** ****ν****  ≠  ****ν**

**If not LMA for  ****ν****, **
**What else?**
**Best fit model, solar *****neutrino***** data only—**
**LWO, long wavelength**
***vacuum***** oscillations (upper panel)**
**Detect LWO via fast oscillations in **
**pp spectrum  (lower panel)**
**(****RSR JCAP 2003)**

- R.S.Raghavan/VT/Aug05

## Slide 57

## Table 1. Error Budget for pp nu flux measurement

| Item | Percent Uncertainty |
| --- | --- |
| Signal/Bgd Statistics ΔS/S% | 2.5 |
| Coinc. Detection Efficiency Δε/ε % | 0.7 |
| No. of Target Nuclei  ΔN/N% | 0.3 |
| Cross Section (Q value) ΔI/I% | 0.3 |
| Cross Section (B(GT))  ΔM/M% | 1.8 |
| Total Flux Uncertainty Δφ/φ% | 3.2 |

**Table 1. Error Budget for pp nu flux measurement**
** ****with 2000 events/5y at S/N=3**

## R.S.Raghavan/VT/Aug05

## R.S.Raghavan/VT/Aug05

## LONG TERM (Yrs) STABILITY--CHEM, OPT,  SCINTILLATION   

**Long term Stability in typical **
**samples (BNL & Bell Labs)**
**All samples above were made at **
** *****low pH-Hi HMVA***** and stored without**
** ****special precautions on air exposure**
**Light yield very stable**
**L(1/e) degrades somewhat (see band)**
**Traced to HMVA degradation from**
** ****air exposure (left)**
**Present InLS contains no HMVA**
**higher stability over several years**
**    ****expected **

**LONG TERM (Yrs) STABILITY--CHEM, OPT,  SCINTILLATION   **

**All samples with hi HMVA**

**InLS(Bell Labs ****(#870.872)**
**Prepared  06/03**
**Measured 05/05;**
**A=0.005**

- R.S.Raghavan/VT/Aug05

## Neutrino detection efficiency:     64%

- Bgd Type                        A1                   C                   D                A2                    B
- Events before Cuts    500000            20000            1000           200000              3x106
- Rate before Cuts       6.17.108              14.6              2.24.10-3      6.17.108               9.49.104
- Overall Rej. Eff.      9.3(38).10-10    6.5(18).10-4       0(1).10-3    6.53(20).10-9     8.80(54).10-6
- Rate After Cuts        5.7(23).10-1    9.5(26).10-3     0(2).10-6           4.03(12)             8.3(5)
- Events After Cuts             6                   13                  0                 1088                264
**Neutrino detection efficiency:     64%**
**Neutrino Event rate:                     40      solar pp per ton In per year**
**Indium Background rate:             13.0 (6)             per ton In per year**
**S/B-ratio:                                       3.08**

**Example of Detailed results:   75x75x75mm Cells; (2x[4x4x4m Cube] **
**L(1/e) = 10m;   Y = 9 h****ν****/keV;   pe/keV = 1.0;   Hits ****≥**** 3 pe**

- R.S.Raghavan/VT/Aug05