geoneutrino radiometric analysis for geosciences [grafg]

DUSEL Experiment Development and Coordination (DEDC)Internal Design Review

July 16-18, 2008Steve Elliott, Derek Elsworth, Daniela Leitner, Larry Murdoch, Tullis C. Onstott and Hank Sobel

Homestake DUSEL Initial Suite of ExperimentsDUSEL Experiment Development and Coordination

Geoneutrino Radiometric Analysis For Geosciences [GRAFG]

Working Group Members• Group Leader/ Heat Producing Elements: P. ILA & Point of Contact

Earth, Atmospheric & Planetary Sciences Dept.,

Massachusetts Institute of Technology

• Heat Flow/Geophysics: W. GosnoldGeology and Geological Engineering, University of North Dakota

• Cosmic-ray Physics: G. I. Lykken, Physics Dept. University of North Dakota

• Antineutrino Detector Instrumentation: P. JagamSNO Collaboration, University of Guelph;

Norm Group Organization, Guelph, Canada


Geoneutrino Radiometric Analysis For Geosciences [GRAFG]

Working Group MembersEducation and Outreach:

1) Prof. M. McCurry, Rural Sociology Dept., South Dakota State University (SDSU), SD

2) Mr. D. Oedekoeven, SDSU West River Agricultural Center, SD.

3) Mr. S. A. Ternes, Grand Forks Public Schools, ND

4) AISES - American Indians in Science and Engineering Society.

5) Ms. Beverly Lutekin, Arlington, MA

Group Members• Solid angles analysis: Prof. R. Pevey,

Nuclear Engineering Dept., Univ. of Tennessee, Knoxville, TN • Geochemistry: F. A. Frey,

Earth Atmospheric and Planetary Sciences, Massachusetts Institute of Technology (MIT) • Bulk Silicate Earth: W. F. McDonough

Geology Dept., Univ. of Maryland, College Park, MD• Large Antineutrino Detector Instrumentation: N. Tolich, Univ. of Washington, WA• Interested Others: Prof. J. Formaggio, Physics Dept. MIT


SCIENCEGeoneutrino Radiometric Analysis For Geosciences

What are geoneutrinos? Geoneutrinos are the antineutrinos produced during

the negative beta decay of the primordial isotopes of the elements in the Earth. The predominant production is from Potassium, Thorium and Uranium, which are also usually referred to as radiogenic Heat Producing Elements (HPE).

HPE Half-life AntineutrinoProduction Rate

based on isotopic masses

Billion years kg-1 sec-1

U-238 4.47 2.69x 104

Th-232 14.0 1.63x107

K-40 1.28 7.41x107


SCIENCEGeoneutrino Radiometric Analysis For Geosciences

Q: What is geoneutrino radiometric analysis?A:Radiometric analysis in general means

measurement of source strengths of the elements from their radio-isotopes. Geoneutrino radiometric analysis is analogous to the well known gamma-ray radiometric analysis of K, Th , U to measure the concentrations of K, Th, U in (rock) samples.

In the present context, geoneutrinos are used instead of gamma-rays.

Source strengths are used for radiometric analysis.


Q: Why study HPE of the Earth’s deep interior?A: (1) Disparity of Terrestrial Heat Estimates

By Geochemistry & Geophysics

Bulk Silicate EarthBulk Silicate EarthGeochemical ModelGeochemical Model

Predicts global radiogenic Predicts global radiogenic heat production ~ 19 TWheat production ~ 19 TW

Terrestrial Heat Flow Terrestrial Heat Flow Geophysics EstimatesGeophysics Estimates

Estimated heat flow fromEstimated heat flow fromthe Earth is ( 30 - 44 )TW the Earth is ( 30 - 44 )TW


Q: Why study HPE of the Earth’s deep interior?A: (2) Are there any heat producing elements (HPE) in the Earth’s core?

• Suggestions and theories are made to account for radiogenic heat producing elements in the core.

Ref: Leading scientists like Herndon, Rama Murty, De Meijer.

• A recent study says that there may be uranium at the lower mantle and outer core boundary.

• The suggestion that there may be a large amount of uranium in the inner core of the Earth is totally unacceptable from high temperature geochemistry point of view because uranium and thorium are not siderophile elements. Siderophile elements form compounds or alloys with iron.


Detection of Geoneutrinos

Geoneutrino detectionAntineutrino target is typically a scintillator, but could be a light emitting radiator also.

The radiation emitted by the interaction of the antineutrinos with the target, sensed by the light sensors, gets converted eventually to an analytical signal.

The energy of the incident antineutrino should be above the interaction threshold energy of the target medium, for the antineutrino to be detected.

Geoneutrino Detector

Basic Schematic


Limitations of geoneutrino detection by majority of existing/planned detectors

1. The large monolithic neutrino detectors built so far were designed and operated for solving problems other than the geoneutrino studies except KamLand.

2. The large-scale detectors built for particle physics research were not optimized to detect geoneutrinos.

3. The detectors based on the principle of detecting neutrinos by inverse beta-decay suffer from threshold energy constraints for the detection of geoneutrinos.


Limitations of geoneutrino detection by majority of existing/planned detectors

4. They do not detect a major fraction of the emitted intensity in the spectral distribution of the geoneutrinos.

5. The detectors which use scintillation techniques suffer from loss of directionality of the neutrino interaction in the detecting medium.

6. They cannot provide information to assign the measured values to corresponding regions of the Earth’s interior.


Current Emphasis

Emphasizing the importance of developing the technology for geoneutrino studies

1) directional sensitivity and

2) radial angular measurement .

Ref.

Winter

De Meijer

Fields and Hochmuth

Batygov


Approach Concepts

The two simple properties of geoneutrinos (electron antineutrinos):

1) Travel in straight lines from point A to B.

Neutrons for example do not travel in a straight line from A to B, they travel in zig zag path.

2) Penetration capability of the entire Earth.

Property (1) provides the directional sensitivity.

Property (2) provides the ability to assay the entire Earth.


Geoneutrino Radiometric Analysis For Geosciences[GRAFG] Approach Concepts

• Cross-sectional schematic of the conical field of view dividing the interior regions of the Earth from the detection point of view.

• The cones C1, C2, C3, C4 completely enclose the inner core, outer core, lower mantle, upper mantle regions in the interior of the Earth.


Cone 1


Cone 2


Cone 3


Cone 4


[GRAFG] Approach Concepts

• The counts in each cone C1, C2, C3, C4 are proportional to the radioactivity in that cone. The component contributions in each cone have to be resolved from the observed total counts in each cone region projected on the surface of the upper half of a spherical detector.

• The counts in the lower half of the spherical detector viewing the cones may be used for determining the background diffuse radiation. This principle was demonstrated in the MUNU (mewnew) Bugey Reactor experiment.


[GRAFG] Approach Concepts

• We propose to design a detector optimized to detect the entire geoneutrino spectrum and to provide directional information to separate the contributions from the different regions of the interior of the Earth. The optimization of the energy threshold for the detection of the geoneutrinos will be based on the spectrum shapes reported for the beta-decaying primordial radioactive isotopes.

• Our goal is to include the entire energy spectrum of the geoneutrinos into the detection mechanism.


OBJECTIVES1- 5

Employing an existing mobile antineutrino detector

1. Develop a radiometric metric method using antineutrinos from the Earth for in-situ determination of U and Th to demonstrate proof-of-concept.

2. Optimize the antineutrino radiometric method to determine HPE in regions inaccessible to conventional sampling methods.

3. Apply the method to investigate correlations with U and Th in different geothermal regions.

4. Interface with high temperature geochemistry knowledge base regarding fractionation of U and Th in Earth's interior.

5. Refine the Bulk Silicate Earth model.


Why is DUSEL the best or only place this experiment can be done?

1) U, Th very low compared to for example SNO detector in Sudbury. That reduces backgrounds immediate shielding requirements.

2) Depth 300’ to 4850’ – providing cosmic ray shielding

3) Testing of post-glacial warming magnitude at strategically located periglacial region of Homestake in South Dakota is of importance to both national and international geophysics communities.

4) Our cross disciplinary project of geophysics and geochemistry will be like a head start in this direction for DUSEL at Homestake


Why is it important to do these experiments in the near future?

The neutrino detection technology has been evolving for more than 50 years and is mature now.

The current trend is towards smaller antineutrino detectors with directional sensitivity.

SONGS1 antineutrino detector is already developed for testing reactor antineutrinos for the purpose of test ban treaty monitoring. CHOOZ and MuNu experiments are also conducted successfully. This is the cutting edge technology.

We propose to apply that technology to geoneutrino radiometric method for geosciences.

Our project is like a head start for the large detector proposals which will be started much later.


Why is it important to do these experiments in the near future?

• The neutrino detection technologies developed to investigate neutrino properties were optimized for in m^3 size detector. Small detector technology proof of concept is already published last year.

• The 1-ton detector designed and tested for Comprehensive Test Ban Treaty applications may be available in the next six months for further tests in the context of detecting geoneutrinos.

• We propose to understand the backgrounds representing part of the geoneutrino spectrum including fission neutrinos in the energy region from 2 MeV - 10 MeV and up to 20 MeV. Thus if prompt approval is given for our proposal and if the construction is kept to the engineering schedule of two years the cost of engineering design can be minimized, and the initial suite of experiments can be started as proposed.


Why important to NSF?

• The proposed geoneutrino radiometric analysis for geosciences will open new opportunities for growth and diversity promoting inter disciplinary research among the disciplines of Geology, Geochemistry and Geophysics. This proposal also promotes inter agency partnerships among academic and national institutions.

• We are proposing to adapt the hardware techniques developed so far and integrate them with the Elastic scattering detection methodology.

• Not only is this approach appropriate for NSF to support but also in developing this methodology NSF will be building a laboratory infrastructure in which other experiments could be carried out.


Expected results and their significance

1) The expected results are supposed to show whether there is radioactivity in the core of the Earth.

2) This is of most significance to research in goescience because this region is inaccessible for investigations by other methods for determining the radioactivity until now.


Expected results and their significance

3) In comparison with large detector proposals for investigating the radioactivity in the deep interior of the earth, the significane of our proposal is that the results are achieved in a shorter time and at a less cost. The larger detectors can improve the precision investing 5 times the time required getting the results by us and at 10 times the cost.

4) Groups who worked or working with larger detectors are also recommending detectors with directional sensitivity. We are developing the directional sensitivity.


Approach to achieve the Objective -1

List of Sub-Proposal Topics:

For Objective 1:

1. Investigation of solid angle dependence

2. Investigation of backgrounds and interferences

3. Design of geoscience goals for instrumentation

4. Investigation of Proof-of-concept (POC)

5. Testing of the POC and draw conclusions

6. Optimization and iteration of item 2 and 3 for depth sensitivity


Approach to achieve theObjective - 2

List of Sub-Proposal Topics:For Objective 2:

1. Investigate calibration of the method for HPE

2. Investigate precision of the method

3. Investigate accuracy of the method


How the list is amalgamated into a program to address the objectives

We have listed above the series of investigations and experiments, needed to be done to achieve the science objectives.

They are listed in the order in which they are needed for a logical progression of steps to achieve the science goals.

From the steps we listed for objectives 1 and 2, to do the whole Earth assay of the primary Heat Producing Elements (HPE) we are developing instruments capable of in-situ measurements as opposed to grab sampling or time consuming and expensive drill core sampling methods.


Proposed Experiments

1. Surface background characterization

2. Underground background characterization

3. Proof of concept (POC) of geoneutrino radiometric analysis for geosciences

4. Experimental study of geothermal exploration


Proposed Experiment - 1

1. SURFACE BACKGROUND CHARACTERIZATION

Involves observation of the influences of local geology on the background recorded by 1 m^3 detector.

Step 1. Borrow the 1 m^3 detector and learn to operate it.

Step 2. Collect existing data from at various locations.

Step 3. Collect supplementary data at locations with dramatically

different local geology.

Step 4. Identify trends in the surface background



2. UNDERGROUND BACKGROUND CHARACTERIZATIONInvolves observation of the interference from cosmic rays and its variation with

depth, and also with local geology.

Step 1. Collect data with 1 m^3 detector, preferably at 5 depths or more, to determine cosmic ray related contributions quantitatively for the assay of HPE in the Earth.

Step 2. Collect data with 1 m^3 detector, preferably at 3 depths or more, to determine contributions quantitatively to study the influence of local geology for the assay of HPE in the Earth.

Step 3. Identify the interferences from cosmic rays in the measured radiometric data from geoneutrinos.

Step 4. Identify the influences of the local geological parameters on the measured radiometric data from geoneutrinos.

Step 5. Analyze all data from experiments 1 and 2 to separate the geoneutrino data from the deep interior of the Earth from cosmic ray influences and local geology.



3. PROOF OF CONCEPT (POC) OF GEONEUTRINO RADIOMETRIC ANALYSIS FOR GEOSCIENCES

• Involves detection a local uranium mine with a given precision. • Step 1. Collect surface data with the 1 m^3 detector at a known

mine with proven reserves of uranium.• Step 2. Analyze the data to determine the uranium in the mine

based on the first two experiments.• Step 3. Compare the measured uranium value in the mine with the

estimated reserve.• Step 4. Draw conclusions about the theory and experiment for the

radiometric methodology using geoneutrinos from deep interior of the Earth.



4. EXPERIMENTAL STUDY OF GEOTHERMAL EXPLORATION

Involves establishing correlation of a heat flow studies with

geoneutrino data

Step 1. Collect surface data with the 1 m^3 detector at known geothermal fields with a wide range of heat flow data.

Step 2. Analyze the data to determine the correlation between the known heat flow data and the measured geoneutrino data based on the first two experiments.

Step 3. Evaluate the geoneutrino method for geothermal exploration.


Facility Needs

Facilities

Space: 15’ x 15’ x 15’ room surface and underground

Depth: 300’ to 4850’

Access: Daily 3 to 5 years

Power: UPS 120V

AC: 20 +/ 5 o C Humidity: 50% +/20% uncontrolled

Equipment: Crane 2 ton block hoist

Communications: Internet

Special materials: Special delivery of air not through shafts; License for radioactive material Storage


Risk identification and management

Potential problems that could affect successful outcome

If the existing meter cubed antineutrino detector

cannot be borrowed in time, then we already have

a back up plan to build a detector from scratch. This may have impact on the successful outcome of the time lines

Potential problems that could affect other experiments or

facility

We do not foresee any potential problems that could

affect other experiments or facility because we do not use any hazardous materials like large quantities of cryogens.


EDUCATION & OUT REACH

Geoneutrino radiometric analysis for geosciences projects has strong potential for Education and Outreach programs because of the multi-disciplines namely geology, geophysics, geochemistry and physics and mainly about Earth’s interior and the DUSEL underground experiments.

Education:

1) Offering undergraduate courses and publication on Open Course Ware

2) ) K12 Education:

4 presentations in four North Dakota schools and 1 trip to SUSEL under consideration.

Outreach: Program for 6 to 9 communities from Cheyenne River,

Pine Ridge, Red Shirt reservations.


Development needs prior to conducting experiments at Homestake

Infrastructure Engineering & Design• Surface room 15’ x 15’ x 15’, A/C

• Power Supply 110V @15 Amps of 8 outlets on 4 sides, total of 32 outlets.

• Security

• Clean room class 2000

• Similar room with the above facilities, underground at 4850’

• Crane 2 ton block hoist.


S-4 activities to be proposed

• Teleconferences

• Trips to Homestake

• Trips to Sandia and LLNL

• Discussions with E&O Groups

• Planning for E& O media presentations & prototypes

• Theoretical Estimations


Schedule Estimated time required and sequence of tasks

starting with S-4 activities

Year 1 – 1st HalfObjective: Project start up

Low radioactivity site selection,

Shielding design System components

acquisition Site preparation Personnel recruitment

Year 1 – 2nd HalfObjective:

Assemble Test Equipment Training of personnel and team

members Assembly of primary test

systems Calibration of primary systems Preliminary test runs above and

below ground Quality control tests, Quality

Assurance tests Evidence evaluation for proof of

sensitivity



Year 2 – 1st HalfObjective: Determination of Sensitivity

• Negotiations for Field deployment 1

• Field deployment at a uranium mine site

• Evaluation of data, Quality control tests

• Science analysis and observations 1

Year 2 – 2nd HalfObjective: Validation at known locations


• Field deployments at selected Heatflow sites





Year 3 – 1st HalfObjective: Quality Assurance Tests


• Field deployment at a uranium mine site



Year 3 – 2nd HalfObjective: Deep Earth assay design- synergy with Physics working Groups

• Evaluation of science and sensitivity of the investigation from Observations 1,2,3

• Science analysis and plans for year 4

• Funding proposals for years 4 and 5



• Years 4 and 5:

Discussions in progress for the design of antineutrino detectors with the required detection sensitivity to assay core of the Earth for

heat producing elements.


Tasks required to refine ISE Project cost estimate

1. Negotiate borrowing the detector developed (Bowden and Bernstein)

This is under negotiation at this time.

2. If the above task is not feasible come up with task required to design and build from scratch. This is also in progress


Thank You

geoneutrino radiometric analysis for geosciences [grafg]

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