Thesis Proposal August 24, 2011. IGY MonitorStandard NM64 (1964) Developed to WHAT IS A NEUTRON MONITOR (NM)? (International Geophysical Year) Design

Analysis of Data from a Calibration Neutron Monitor at Doi Inthanon and a

Ship-Borne Neutron Monitor

WARAPORN NUNTIYAKUL 5238713 SCPY/D

Thesis ProposalAugust 24, 2011

OUTLINE

1. INTRODUCTION

2. OBJECTIVES

3. EXPECTED ADVANTAGES

4. METHODOLOGY AND SCOPE

5. RESEARCH PLANNING

6. ACKNOWLEDGEMENTS

7. REFERENCES

2

Neutron Monitor (NM) is a ground-based detector designed to measure the number of high-energy charged particles striking the Earth's atmosphere from outer space.

IGY Monitor Standard NM64 (1964)Developed to

WHAT IS A NEUTRON MONITOR (NM)?

(International Geophysical Year)

1. INTRODUCTION… 3

Design by Simpson (1948)Design by Hatton and Carmichael

The efficiency of neutron counters to record evaporation neutrons produced inThe lead of a monitor increased from 1.9% for the IGY to 5.7% for the NM64,an increase of 3.3 times the counting rateper unit area of lead producer.

BARE

Detection Method: Older type-proportional counter filled with BF3: n + 10B + 7Li Newer type-proportional counter filled with 3He: n + 3He p + 3H

A large instrument, weighing 32 tons (18 tube NM64 is “supermonitor”)

Detects secondary neutrons generated by collision of primary cosmic rays with air molecules.

NM64

CHARACTERISTIC OF NEUTRON MONITOR


Image Credit: PSNM station at Doi Inthanon,

Chiang Mai, Thailand

Image Credit : Paul Evenson, January 2009

NEUTRON MONITOR PRINCIPLE

An incoming hadron interacts with a nucleus of lead to produce several low energy neutrons.

These neutrons thermalize in polyethylene or other material containing a lot of hydrogen

Thermal neutrons cause fission reaction in a 10B (7Li +4He) or 3He (3H + p) gas proportional counter.

The large amount of energy released in the fission process dominates that of all penetrating charged particles. There is essentially no background.

5


Geomagnetic cutoff rigidity; Pc are a quantitative measure of the shielding provided by the earth’s magnetic field, was estimated from

Rigidity; P is a concept used to determine the effect of particular magnetic fields on the motion of the charged particles. It is defined as

Early period: geomagnetic-dipole momentLater period: the effect of the higher-order terms of the magnetic field Final period: numerical calculation of cosmic-ray orbits in the geomagnetic field

WHAT ARE THE RIGIDITY AND CUTOFF RIGIDITY ?


P = B ρ = p/qRigidity

Magnetic field

Gyroradius of particle

Momentum

Charge

Note: gyration depends on pitch angle

cPc dPhPYtLoLaPTtPMPGhtPN ),(),,,(),()(),,(

NEUTRON MONITOR LATITUDE SURVEYS

Transportable Monitor

dPhPYtPMPGhtPNL

Pcc

),(),()(),,(Differential Response

fn.


),(),()( hPYtPMPGdP

dNccc

c

Counting Rate

SCIENTIFIC BACKGROUND

Galactic cosmic ray spectrum

geomagnetic Transmissionheliospheric Modulation

Yield function

(not to scale)

Assuming T as a box function, L is a limiting rigidity as a numerical convenience

Doi Inthanon

THE WORLDWIDE NETWORK OF NM

Image Credit : http://physik.uibk.ac.at


WHY USE A CALIBRATION NM?

TO DERIVE DIFFERENTIAL RESPONSE FUNC. OR ENERGY SPECTRA


Moraal et al. (2000)

Fig 1. Example of expected differential response function for 11 inter-calibrated neutron monitors.

dN/dP = differential response fn.

Pc1 = cutoff rigidity at location 1Pc1 = cutoff rigidity at location 2

N(Pc1) = count rate at Pc1

N(Pc2) = count rate at Pc2

WHAT IS A CALIBRATION NM?


a = LND25382, 51 mm in diameter c = lead producer with diameters 101 and 193 mm

b = polyethylene(PE) moderator with inner d = reflector with diameters 194 and 350 mm

and outer diameters of 60.5 and 99.5 mm

The name of Calibrator is “CALMON”

COUNTS

BAROMETRIC PRESSURE

HIGH VOLTAGE

TEMPERATURE

GPS CO-ORDINATES

GPS ALTITUDE

WHAT THE SYSTEM RECORDS ?

1. INTRODUCTION 11



2.1 To compare count rates of the calibration monitor under various conditions.

The residual uncertainties in the intercalibration are mainly due to

(a) Different responses to primary intensity variations of NM of

different design.(b) Different atmospheric (pressure and

temperature) responses of the monitors.(c) Environmental differences due to the fact that

the calibrator can usually not be transported to the identical environment of the stationary neutron monitor.

Moraal et al. (2000)The calibration accuracy of Neutron Monitors needs to be within 0.2%.

2. OBJECTIVES 12

2.2 To determine the best method to characterize the evolution of the cosmic ray spectrum using data from the series of latitude surveys conducted from 1994 through 2007.

3. EXPECTED ADVANTAGES 13

Calibration Procedure Ability to compare the cosmic ray intensity at any two sites with different cutoff rigidity and atmospheric depth.

Latitude Surveys Derive useful differential response functions from the neutron monitor network. Develop optimal methods for extracting cosmic ray spectra from latitude surveys Provide correct information on how the solar cycle affects cosmic rays.

PRINCESS SIRINDHORNNEUTRON MONITOR

Location: At Doi Inthanon , Chiang Mai, Thailand.

Design: 18 BP28-NM64

Altitude: 2,565 m above sea level

Geographic Coordinates: 18.59 ๐ North98.49 ๐ East

Vertical cutoff rigidity: 16.8 GV at Chiang Mai

Standard Pressure:750.6 hPa (563 mmHg)

Barometric Coefficient:-0.623%/hPa (-0.83%/mmHg)

http://www.dfi.uchile.cl

4.1 THE CALIBRATION PROCEDURE AT PSNM STATION

4. METHODOLOGY AND SCOPE… 14



PRINCESS SIRINDHORN NEUTRON MONITOR SET UP THE CALIBRATION NEUTRON MONITOR

ELECTRONICS HEAD

from BARTOL RESEARCH INSTITUTE UNIVERSITY OF DELAWARE, USA

from POTCHEFSTROOM CAMPUS NORTH - WEST UNIVERSITY, SA

Original PSNM Station

Modified PSNM Station (April 2010)


Test for stability and repeatability of the Calibrator with eliminating of environmental effects.Table 1. 15 configurations of the calibration procedure

The Calmon data were put on the Doi Inthanon FTP. The URL is ftp://203.113.110.146/CalmonData/


Fig 2. The ratio of the count rates of the IGY and calibration neutron monitor as function of the height of the calibration neutron monitor above a concrete Floor, with different amounts of water and brick underneath the calibrator.

Krüger et al. (2010)


Determine a normalization factor for the count rate of the stationary neutron monitor relative to the others in the world-wide network.

Doi Inthanon


0.00545

0.00550

0.00555

0.00560

0.00565

0.00570

0.00575

0.00580

0 10 20 30 40 50 60 70 80

Ratio

Cal

/NM

Height of water (cm)

Doi Inthanon 140 cm

Doi Inthanon 70 cm

Potchefstroom

Preliminary Results report in International Cosmic Ray Conference (ICRC), Beijing 2011

Fig 3. The ratio of the count rates of the Potchefstroom NM (open circles) and the NM at Doi Inthanon as Function of varying heights of water beneath the calibrator.

1st experimentPerformed in Potchefstroom, SA

2nd experimentPerformed in Kiel, GE[from March to May, 2008]

3rd experimentPerformed in Doi Inthanon, TH[from Nov, 2009 to Jun, 2010]

Decrease 1.56%[Doi Inthanon 140 cm]

Decrease 4.2%[Doi Inthanon 70 cm]

Decrease 4.0%[Potchefstroom]


The counting decreases with an increase in the amount of water, and the counting rate levels off when the water level 30 cm

To quantify the calibration process, consider two NMs at different cutoff rigidities and altitudes, with different efficiencies (due to difference in type of neutron monitor, number of counters, and different environment). Suppose NM1 is calibrated against the calibrator at time t1, and similarly NM2 at time t2.

Then we have the following five measurements:

• At time t1 the counting rate (cr.) of NM1 is N1,1

• At time t2 the cr. of NM1 is N1,2

• At time t2 the cr. of NM2 is N2,2

• At t1 the cr. of the calibrator at NM1 is C1,1

• At t2 the cr. of the calibrator at NM2 is C2,2

At time t2 the counting rate of the calibrator at NM1 can then be calculated as C1,2 = (N1,2/N1,1)*C1,1.

Determine the ratio of efficiency of the two NMs.

The measured ratio of the two NMs at time t2

The measured ratio of the calibrator counts at the two positions.


NMcalibratorcalculation

measurement

t1, Potchefstroom t 2, SANAE NM64/NMD t 2, Kiel t 2, Doi Inthanon

SANAE/Kiel/Thailand NM 557152/30795 611133 2195452

Calibrator 10197 11703 4520 12123

IGY in Potchefstroom 216767 206104 217211 215230

Efficiency ratio (Reff) 1.000 2.240/0.124 6.360 8.519

Pc (GV) Pressure (mm Hg)

β at NM

(%/mm Hg)

β at sea level

(%/mm Hg)

Efficiency ratio, Reff

Reff at sea level

SANAE NM64 0.73 660 0.97 0.96 2.240 2.800

SANAE NMD 0.73 660 1.01 1.00 0.124 0.155

Kiel 2.29 755 0.96 0.96 6.360 6.360

Potchefstroom 6.94 652 0.99 0.972 1.000 1.000

Doi Inthanon 16.8 563 0.83 0.815 8.519 10.649

Table 2. Hourly counting rates during the calibrations

Table 3. Characteristics, barometric coefficient, and efficiency ratio of each NM relative to the Potchefstroom NM.

Preliminary Results report in International Cosmic Ray Conference (ICRC), Beijing 2011


U.S. Coast Guard icebreakers, the Polar Sea or the Polar Star carry a Neutron monitor standard 3-NM64

4.2 ANALYZE THE DATA FROM A SHIP-BORNE MONITOR WITH THREE COUNTER TUBES.Made trips across the Pacific ocean from Seattle to Antarctica and back, over a wide range of cutoff rigidities, over 1994 to 2007.

U.S. Coast Guard icebreakers

Fig 4.


The latitude survey data were put on the Bartol FTP. The URL is as follows:ftp://ftp.bartol.udel.edu/pyle/OtherData/LatSurvSegments/

Part of the listing:

…

A: S(eattle)-C(utoff)E(quator)B: CE - M(cMurdo) C: M - CE D: CE - S.

The format is as follows:YY/MM/DD HH:MM:SS Vcutoff Rate1 Rate2

…

Download and analyze the latitude survey data.

Fig 5. Sample fit of a segment’s data to a Dorman function, along with the corresponding derivative

Bieber et al. (2003)

Latitude or Longitude changed by greater than 0.002 degrees during the hour (>0.14 miles/hour)


Fig 6. Data (left) and model fit (Right) to the moderated neutron detector latitude survey.

Yield Function

- This term is due to the energy dependence of the neutron production and expresses the x-dependence of Y in high-energy region- This term expresses the decrease of the production mainly due to the decrease of the number of effective nucleons in the atmosphere with the increase of x and with the decrease of u

Characterize Cosmic Ray Spectra. [Nagashima et al (1989)]


u = U/U0 U = the total energyU0 = the rest energy-------------------------x = pressure in mbar (atmospheric depth)

Fig 7. Residuals (counts/second) from the fit shown in Figure 6 as a function of geomagnetic cutoff.

4. METHODOLOGY AND SCOPE 25

5. RESEARCH PLANNING 26

Number Details Time period Month

1. Theoretical study and reviews

6 months November 2010-May 2011

2. Data analysis 9 months May 2011-Febuary 2012

3. Data characterization and synthesizing existing and/ or new concepts

8 months October 2011-June 2012

4. Interpretation 9 months June 2012-March 2013

5. Writing thesis 6 months March 2013-September 2013

RGJ Scholarship

PSNM Mahidol U.

Prof. David Ruffolo

Prof. Paul Evenson

Dr. Alejandro Sáiz

Space Physics and Energetic Particles Group

6. ACKNOWLEDGEMENTS 27

Bieber, J.W., and Evenson, P. (1995), Spaceship Earth – an Optimized Network of Neutron Monitors, Proc. 24th International Cosmic Ray Conference (Rome) 4, 1078-1081.Bieber, J.W., Evenson, P., Humble, J.E., and Duldig, M.L. (1997), Cosmic Ray Spectra Deduced from Neutron Monitor Surveys, Proc. 25th International Cosmic Ray Conference (Durban) 2, 45-48.Bieber, J.W., Clem, J., and Evenson, P. (1997), Efficient computation of apparent cutoffs, Proc. 25th International Cosmic Ray Conference (Durban) 2, 389-392.Bieber, J.W., Clem, J., Duldig, M.L., Evenson, P., Humble, J.E., and Pyle, R. (2001), A continuing yearly neutron monitor latitude survey: Preliminary results from 1994-2001, Proc. 27th International Cosmic Ray Conference (Hamburg) 10, 4087-4090. Bieber, J.W., Clem, J., Duldig, M.L., Evenson, P., Humble, J.E., and Pyle, R. (2001), New method of observing neutron monitor multiplicities, Proc. 27th International Cosmic Ray Conference (Hamburg) 10, 4091-4094. Bieber, J.W., Clem, J.M., Duldig, M.L., Evenson, P.A., Humble, J.E., Pyle, R. (2003), Cosmic Ray Spectra and the Solar Magnetic Polarity: Preliminary Results from 1994-2002, Solar Wind Ten: Proceedings of the Tenth International Solar Wind Conference, Pisa, Italy, AIP Conference Proceedings. 679, 628-631.

7. REFERENCES… 28

Bieber, J.W., Clem, J.M., Duldig, M.L., Evenson, P., Humble, J.E., Pyle, R. (2004), Latitude survey observations of neutron monitor multiplicity, JGR. 109, A12106. Clem, J.M., David P. Clements, Joseph Esposito, Evenson P., David H., and Jacques L’Heureux (1996), Solar modulation of cosmic electrons, APJ. 464, 507-515.Clem, J.M., Bieber, J.W., and Evenson P. (1997), Contribution of obliquely incident particles to neutron monitor counting rate, J. Geophys. Res. 102, 26919- 26926Clem, J.M. (1999), Atmospheric yield functions and the response to secondary particles of neutron monitors, Proc. 26th International Cosmic Ray Conference (Salt Lake City) 7, 317-320.Clem, J.M., and Dorman, L.I. (2000), Neutron Monitor Response Functions, Space Sci. Rev. 93, 335-359.Dorman, L.I., Villoresi, G., Iucci, N., Parisi, M., Parisi, M.I., Tyasto, O.A., Danilova, A., and Ptitsyna, N.G. (2000), Cosmic ray survey to Antarctica and coupling functions for neutron component near solar minimum (1996-1997): 3. Geomagnetic effects and coupling functions, J. Geophys. Res. 105, 21,047.

7. REFERENCES… 29

Evenson, P., Bieber, J.W., Clem, J., and Pyle, R. (2005), Neutron monitor temperature coefficients: measurements for BF3 and 3He Counter tubes, Proc. 29th International Cosmic Ray Conference (Pune) 2, 485-488.Hatton, C.J., and Carmichael, H. (1964), Experimental investigation of the NM-64 neutron monitor, Can. J. Phys. 42, 2443-2472.Hatton, C.J. (1971), The Neutron Monitor, in Progress in Elementary Particle and Cosmic Ray Physics X, Ed. J.G. Wilson and S.A. Wouthuysen, North Holland Publishing Co., Amsterdam.Hess, W.N., Patterson, H.W., and Wallace, R. (1959), Cosmic Ray Neutron Energy Spectrum, Phys. Rev. 116, 445-457.Krüger, H., Moraal, H., Bieber, J.W., Clem, J.M., Evenson, P., Pyle, K.R., Duldig, M.L., and Humble, J.E. (2003), First Results of a Mobile Neutron Monitor to Intercalibrate the Worldwide Network, Proc. 28th International Cosmic Ray Conference (Tsukuba) 6, 3441-3444.Krüger, H., Moraal, H., Bieber, J.W., Clem, J.M., Evenson, P., Pyle, K.R., Duldig, M.L., and Humble, J.E. (2005), Latitude surveys with a calibration neutron monitor, Proc. 29th International Cosmic Ray Conference (Pune) 2, 473-476.Krüger, H. (2006), A calibration neutron monitor for long-term cosmic ray modulation studies, Ph.D. thesis, North-West Univ., Potchefstroom, South Africa.

7. REFERENCES… 30

Krüger, H., Moraal, H., Bieber, J.W., Clem, J.M., Evenson, P., Pyle, K.R., Duldig, M.L., and Humble, J.E. (2007), Experiments with two calibration neutron monitors, Proc. 30th International Cosmic Ray Conference (Mérida). 1, 741-744.Krüger, H., Moraal, H., Bieber, J.W., Clem, J.M., Evenson, P., Pyle, K.R., Duldig, M.L., and Humble, J.E. (2008), A calibration neutron monitor: Energy response and instrumental temperature sensitivity, J. Geophys. Res. 113, A08101, 6pp., doi:10.1029/2008JA013229.Krüger, H., Moraal, H. (2010), A calibration neutron monitor: Statistical accuracy and environmental sensitivity, ADV. Space. Res. 46, 1394-1399.Lumme, M., Nieminen, M., Peltonen, J., Torsti, J.J., Vainikka, E., and Valtonen, E. (1983a), Multiplicity Response Function of the Double Neutron Monitor at Turku, Proc. 18th International Cosmic Ray Conference (Bagelore) 3, 538-541.Mischke, C.F.W., Stoker, P.H., and Duvenage, J. (1973), The Neutron Moderated Detector and the Determination of Rigidity Dependence of Protons From the ½ September 1971 Solar Flare, Proc. 13th International Cosmic Ray Conference (Denver) 2, 1570-1575.Moraal, H., Potgieter, M.S., Stoker, P.H., and van der Walt, A.J. (1989), Neutron Monitor Latitude Survey of the Cosmic Ray Intensity During the 1986/87 Solar Minimum, J. Geophys. Res. 94, 1459-1464.

7. REFERENCES… 31

Moraal, H., Belov, A., and Clem, J.M. (2000), Design and co-ordination of multi-station international neutron monitor networks, Space Sci. Rev. 93, 283-303.Moraal, H., Benadie, A., de Villiers, D., Bieber, J.W., Clem, J.M., Evenson P., Pyle, K.R., Shulman, L., Duldig, M.L., and Humble, J.E. (2001), A mobile neutron monitor to intercalibrate the worldwide network, Proc. 27th International Cosmic Ray Conference (Hamburg) 8, 4083-4086.Moraal, H., Krüger, H., Benadie, A., De Villiers, D. (2003), Calibration of the Sanae and Hermanus neutron monitors, Proc. 28th International Cosmic Ray Conference (Tsukuba) 7, 3453-3456.Pyle, R., Evenson, P., Bieber, J.W., Clem, J.W., Humble, J.E., and Duldig, M.L. (1999), The Use of 3He tubes in a Neutron Monitor Latitude Survey, Proc. 26th International Cosmic Ray Conference (Salt Lake City) 7, 386-389.

Raubenheimer, B.C., and Stoker, P.H. (1974), Attenuation Coefficient of a Neutron Monitor, J. Geophys. Res. 79, 5069.Sáiz, A., Ruffolo, D., Rujiwarodom, M., Bieber, J.W., Clem, J., Evenson, P., Pyle, R., Duldig, M.L., Humble, J.E. (2005), Relativistic Particle Injection and Interplanetary Transport during the January 20, Proc. 29th International Cosmic Ray Conference (Pune) 1, 229-232.

7. REFERENCES… 32

Simpson, J.A. (1948), The Latitude Dependence of Neutron Densities in the Atmosphere as a Function of Altitude, Phys. Rev. 73, 389–395.Stoker, P.H. (1981), Primary Spectral Variations of Cosmic Rays Above 1 GV, . 17th International Cosmic Ray Conference (Paris) 3, 193-196.Stoker, P.H., and Moraal, H. (1995), Neutron Monitor Latitude Surveys at Aircraft Altitudes, Astrophys. Space Sci. 230, 365-373.Stoker, P.H., Dorman, L.I., and Clem, J.M. (2000), Neutron motitor design improvements, Space Sci. Rev. 93, 361-380.Usoskin, I.G., Kovaltsov, G.A., Kananen, H., and Tanskanen, P. (1997), The World Neutron Monitor Network as a Tool for the Study of Solar Neutrons, Ann. Geophysicae, 15, 375-386.

7. REFERENCES 33

EFFECTIVE CUTOFF RIGIDITY SKY MAP…

8. SUPPORT SLIDES 34

Image Credit: Clem et al. (1997)Apparent Cutoff is a new method for calculating geomagnetic cutoffs that incorporates obliquely incident primaries, using it to interpret a sea level neutron monitor latitude survey.Stoker (1995) suggested that oblique particles might also be responsible for anomalies in neutron monitor latitude surveys.

EFFECTIVE CUTOFF RIGIDITY SKY MAP


Image Credit: Clem et al. (1997)


RESULT EFF. VERTICAL & APPARENT CUTOFF (GV)

Image Credit: Clem et al. (1997)


NOTE OF 15 CONFIGURATIONS

Fig 3. (a) The ratio of the count rates of the Pochefstroom neutron monitor (IGY) and Calibrator as function of thickness of absorbing material underneath the calibrator, with the calibrator in an enclosed building. The calibrator was kept at a fixed height of 40 cm above the floor. (b) The same ratio as function of height on the open roof of building, while the calibrator was kept immediately above the water level; (c) a repetition of (b) on ground level far removed from any building.

3.5% decrease in the count rate, reaching a minimum for an amount of 30 g/cm2 of moderator/absorber.

The decrease in the count rate with an increase in the amount of water beneath the calibrator is 5.3%, with the saturation point at 20.

The count rate decreased by 3.8%, but it saturated again at 20 cm.

Krüger et al. (2010)


RESULT OF KRUGER (2010)

Rigidity P (GV)

Pairs of response functions at 11 and 22 year intervals illustrate the “spectral crossover” effect

SPECTRAL CROSSOVER



How to analyze CALMON data in each configuration…

1. Dowload the data from ftp://203.113.110.146/CalmonData/

2. Calculate the values of fracDOY, Count/hour, N, Tave, pave

File name: secselhour

ftp://203.113.110.146/CalmonData/

3. Check and analyze the data



Fig 1



Fig 2



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Fig 7

Documents

Thesis Proposal August 24, 2011. IGY MonitorStandard NM64 (1964) Developed to WHAT IS A NEUTRON MONITOR (NM)? (International Geophysical Year) Design