WARAPORN NUNTIYAKUL 5238713 SCPY/D

1. Analysis of Data from a Calibration Neutron Monitor at DoiInthanon and a Ship-Borne Neutron Monitor Thesis Proposal August 24, 2011 WARAPORN NUNTIYAKUL 5238713 SCPY/D

2. 2 OUTLINE • INTRODUCTION • OBJECTIVES • EXPECTED ADVANTAGES • METHODOLOGY AND SCOPE • RESEARCH PLANNING • ACKNOWLEDGEMENTS • REFERENCES

3. 1. INTRODUCTION… 3 WHAT IS A NEUTRON MONITOR (NM)? 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. Developed to IGY Monitor Standard NM64 (1964) (International Geophysical Year) Design by Hatton and Carmichael Design by Simpson (1948) The efficiency of neutron counters to record evaporation neutrons produced in The 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 rate per unit area of lead producer.

4. 1. INTRODUCTION… 4 CHARACTERISTIC OF NEUTRON MONITOR • 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 BARE Image Credit: PSNM station at DoiInthanon, Chiang Mai, Thailand • Detection Method: • Older type-proportional counter • filled with BF3: n + 10B  + 7Li • Newer type-proportional counter • filled with 3He: n + 3He  p + 3H

5. 1. INTRODUCTION… 5 NEUTRON MONITOR PRINCIPLE 5 • 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. Image Credit : Paul Evenson, January 2009

6. 1. INTRODUCTION… 6 WHAT ARE THE RIGIDITY AND CUTOFF RIGIDITY ? Rigidity; Pis a concept used to determine the effect of particular magnetic fields on the motion of the charged particles.It is defined as Rigidity Momentum P  = B ρ  = p/q Magnetic field Charge Gyroradius of particle Note: gyration depends on pitch angle Geomagnetic cutoff rigidity; Pc are a quantitative measure of the shielding provided by the earth’s magnetic field, was estimated from Early period: geomagnetic-dipole moment Later period: the effect of the higher-order terms of the magnetic field Final period: numerical calculation of cosmic-ray orbits in the geomagnetic field

7. 1. INTRODUCTION… 7 NEUTRON MONITOR LATITUDE SURVEYS Transportable Monitor (not to scale) Galactic cosmic ray spectrum heliosphericModulation geomagnetic Transmission Scientific Background Yield function Counting Rate AssumingTas a box function,L is a limiting rigidity as a numerical convenience Differential Response fn.

8. 1. INTRODUCTION… 8 THE WORLDWIDE NETWORK OF NM DoiInthanon Image Credit : http://physik.uibk.ac.at

9. 1. INTRODUCTION… 9 WHY USE A CALIBRATION NM? TO DERIVE DIFFERENTIAL RESPONSE FUNC. OR ENERGY SPECTRA dN/dP = differential response fn. Pc1 = cutoff rigidity at location 1 Pc1 = cutoff rigidity at location 2 N(Pc1) = count rate at Pc1 N(Pc2) = count rate at Pc2 Moraal et al. (2000) Fig 1. Example of expected differential response function for 11 inter-calibrated neutron monitors.

10. 1. INTRODUCTION… 10 WHAT IS A CALIBRATION NM? The name of Calibrator is “CALMON” • 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

11. 1. INTRODUCTION 11 WHAT THE SYSTEM RECORDS ? • COUNTS • BAROMETRIC PRESSURE • HIGH VOLTAGE • TEMPERATURE • GPS CO-ORDINATES • GPS ALTITUDE Image Credit: PSNM station at DoiInthanon, Chiang Mai, Thailand

12. 2. OBJECTIVES12 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%. 2.2 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.

13. 3. EXPECTED ADVANTAGES13 • 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.

14. 4. METHODOLOGY AND SCOPE…14 4.1 THE CALIBRATION PROCEDURE AT PSNM STATION PRINCESS SIRINDHORN NEUTRON MONITOR Location: At DoiInthanon , Chiang Mai, Thailand. Design: BP28-NM64 Altitude: 2,565 m above sea level Geographic Coordinates: 18.59๐ North 98.49๐ 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

15. 4. METHODOLOGY AND SCOPE…15 PRINCESS SIRINDHORN NEUTRON MONITOR SET UP THE CALIBRATION NEUTRON MONITOR Original PSNM Station ELECTRONICS HEAD Modified PSNM Station (April 2010) Image Credit: PSNM station at DoiInthanon, Chiang Mai, Thailand from BARTOL RESEARCH INSTITUTE UNIVERSITY OF DELAWARE, USA from POTCHEFSTROOM CAMPUS NORTH - WEST UNIVERSITY, SA

16. 4. METHODOLOGY AND SCOPE…16 • 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 DoiInthanon FTP. The URL is ftp://203.113.110.146/CalmonData/

17. 4. METHODOLOGY AND SCOPE…17 Krüger et al. (2010) 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.

18. 4. METHODOLOGY AND SCOPE…18 • Determine a normalization factor for the count rate of the stationary neutron monitor relative to the others in the world-wide network. DoiInthanon

19. 4. METHODOLOGY AND SCOPE…19 Preliminary Results report in International Cosmic Ray Conference (ICRC), Beijing 2011 1st experiment Performed in Potchefstroom, SA 2nd experiment Performed in Kiel, GE [from March to May, 2008] 3rd experiment Performed in DoiInthanon, TH [from Nov, 2009 to Jun, 2010] Decrease 1.56% [DoiInthanon 140 cm] Decrease  4.0% [Potchefstroom] Decrease  4.2% [DoiInthanon 70 cm] The counting decreases with an increase in the amount of water, and the counting rate levels off when the water level  30 cm Fig 3. The ratio of the count rates of the Potchefstroom NM (open circles) and the NM at DoiInthanon as Function of varying heights of water beneath the calibrator.

20. 4. METHODOLOGY AND SCOPE…20 • Determine the ratio of efficiency of the two NMs. 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. NM calculation calibrator measurement The measured ratio of the two NMs at time t2 The measured ratio of the calibrator counts at the two positions.

21. 4. METHODOLOGY AND SCOPE…21 Preliminary Results report in International Cosmic Ray Conference (ICRC), Beijing 2011 Table 2. Hourly counting rates during the calibrations Table 3. Characteristics, barometric coefficient, and efficiency ratio of each NM relative to the Potchefstroom NM.

22. 4. METHODOLOGY AND SCOPE…22 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, the Polar Seaor the Polar Star carry a Neutron monitor standard 3-NM64 U.S. Coast Guard icebreakers Fig 4.

23. 4. METHODOLOGY AND SCOPE…23 • Download and analyze the latitude survey data. The latitude survey data were put on the Bartol FTP. The URL is as follows: ftp://ftp.bartol.udel.edu/pyle/OtherData/LatSurvSegments/ Bieber et al. (2003) 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/DDHH:MM:SSVcutoff Rate1 Rate2 Fig 5. Sample fit of a segment’s data to a Dorman function, along with the corresponding derivative … Latitude or Longitude changed by greater than 0.002 degrees during the hour (>0.14 miles/hour)

24. 4. METHODOLOGY AND SCOPE…24 • Characterize Cosmic Ray Spectra.[Nagashima et al (1989)] 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 u = U/U0 U = the total energy U0= the rest energy ------------------------- x = pressure in mbar (atmospheric depth) Fig 6. Data (left) and model fit (Right) to the moderated neutron detector latitude survey.

25. 4. METHODOLOGY AND SCOPE25 Fig 7. Residuals (counts/second) from the fit shown in Figure 6 as a function of geomagnetic cutoff.

26. 5. RESEARCH PLANNING 26

27. 6. ACKNOWLEDGEMENTS 27 Prof. David Ruffolo RGJ Scholarship PSNM Mahidol U. Prof. Paul Evenson Dr. Alejandro Sáiz Space Physics and Energetic Particles Group

28. 7. REFERENCES…28 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.

29. 7. REFERENCES…29 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- 26926 Clem, J.M. (1999), Atmospheric yield functions and the response to secondary particles of neutron monitors, Proc. 26thInternational 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.

30. 7. REFERENCES…30 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 PhysicsX, 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.

31. 7. REFERENCES…31 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.

32. 7. REFERENCES…32 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.

33. 7. REFERENCES33 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.

34. 8. SUPPORT SLIDES34 EFFECTIVE CUTOFF RIGIDITY SKY MAP… 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.

35. 8. SUPPORT SLIDES35 EFFECTIVE CUTOFF RIGIDITY SKY MAP Image Credit: Clem et al. (1997)

36. 8. SUPPORT SLIDES36 RESULT EFF. VERTICAL & APPARENT CUTOFF (GV) Image Credit: Clem et al. (1997)

37. 8. SUPPORT SLIDES37 NOTE OF 15 CONFIGURATIONS

38. 8. SUPPORT SLIDES38 RESULT OF KRUGER (2010) 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) 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.

39. 8. SUPPORT SLIDES39 SPECTRAL CROSSOVER Pairs of response functions at 11 and 22 year intervals illustrate the “spectral crossover” effect Rigidity P (GV)

40. 8. SUPPORT SLIDES40 How to analyze CALMON data in each configuration… Dowload the data from ftp://203.113.110.146/CalmonData/ 2. Calculate the values of fracDOY, Count/hour, N, Tave, pave File name: secselhour

41. 8. SUPPORT SLIDES41 How to analyze CALMON data in each configuration… 3. Check and analyze the data Fig 1

42. 8. SUPPORT SLIDES42 How to analyze CALMON data in each configuration… Fig 2

43. 8. SUPPORT SLIDES43 How to analyze CALMON data in each configuration… Fig 3

44. 8. SUPPORT SLIDES44 How to analyze CALMON data in each configuration… Fig 4

45. 8. SUPPORT SLIDES45 How to analyze CALMON data in each configuration… Fig 5

46. 8. SUPPORT SLIDES46 How to analyze CALMON data in each configuration… Fig 6

47. 8. SUPPORT SLIDES47 How to analyze CALMON data in each configuration… Fig 7