Fhon’s Journey: Neutron Monitors in Thailand and at the University of Wisconsin-River Falls

Hi! I’m Dr. Waraporn “Fhon” Nuntiyakul. I’m a lecturer at Chandrakasem Rajabhat University (CRU). I come from Thailand, where there are not many astrophysicists. Many Thai people still believe in astrology but not astronomy. I want to educate future students to make them think in a scientific way rather than to believe a fortune teller. I have about 10 students are interested in astrophysics research in CRU.

Astrophysics research team at CRU in Bangkok, Thailand.
Astrophysics research team at CRU in Bangkok, Thailand. This photo shows five students of the ten students. From left to right: Ya, June, Beer, Mud and Juy. Ya and June are the second year undergraduate students, Beer and Juy are the fifth year undergraduate students and Mud (only one male in our group) is the first year undergraduate student.

This summer is really a special summer for me. I have a chance to visit to University of Wisconsin River Falls in the US to give some talks about my research. I work in astrophysics field, studying cosmic rays. We have a detector called a neutron monitor in Thailand. Thailand is a special location, where it has the highest cutoff rigidity in the world, which means only particles that have high energy can enter the atmosphere. I focus my studies on the Galactic cosmic rays (GCR), the which are influenced by solar activity as they arrive at the Earth. When we are in solar maximum there are less GCR and vice versa when we are in solar minimum, less activities, there are more GCR. So by studying this we can learn about our Sun.

The inside of the Princess Sirindhorn Neutron Monitor station at Doi Inthanon, Chiang Mai, Thailand. One slab of polyethylene reflector has been removed in order to show the lead producer inside. At the far end of the station, one of the three bare counters is visible.

When I first came to River Falls in summer, I thought that I only have to give only seminars, I didn’t expect to supervise students’ project. It turns out to be very impressive. I love that students always want to learn, they want to know things and the most important thing, they never give up. When they did something wrong and have to do the whole thing again, they are willing to do it. I think this spirit is important, seek to learn, seek to know no matter how hard work they may encounter, they still want to learn. I also learn from them because every week these students have to present their work to progress report and to share some knowledge they did with the others. Especially, in my relevant work, I learn more when I supervise Laura and Kyle (photo below). They always come up with many questions to ask me. We learn together during the progress of their work. Seeing their development makes me happy.

The neutron monitor and the bare at the University of Wisconsin – River Falls (UWRF). Fhon is the right of the photo. Two undergraduate students, Laura Moon and Kyle Lueckfeld, are interested ine working on particle transport simulation using Monte Carlo (Fluka) methods. Both of them are simulating particles detected by the neutron monitor (left detector), covered with white polyethylene reflector, and bare monitor (right detector), covered with wood box.
The neutron monitor and the bare at UWRF (cont). From left to right: Joe, Prof. James “Jim” Madsen, Nick, Kyle, Vanessa, Kim, Nick, Kevin, Hanna, Fhon, Sam, Justin, Laura who share research experiences together in the summer.
The neutron monitor and the bare at UWRF (cont). Fhon is the middle. The left and right position are Samantha and Robert who also are in our group in this summer.

I will use my experience in this summer to teach my students in Thailand. I want to thank Prof. James “Jim” Madsen and Assist. Prof. Suruj Seunarine for giving me a chance to come here and taking care of me while I live in River Falls. Thank you Prof. Paul Evenson for introducing me to Jim. Paul is both my former Ph.D international co-advisor and a father-like figure to me. I want to thank my Ph.D advisor, Prof. David “Dave” Ruffolo, who is my role model for being a good teacher and good researcher.  I want to thank Dr. Alejandro Saiz “Alex” Rivera, Dr. Achara “Kim” Seripienlert and Dr. Pierre-Simon Mangeard for your brilliant comments and suggestions to get the wonderful project.

Paul was giving a talk of the electronic workshop in Bangkok, Thailand. He gave a similar talk to the summer undergraduates at UWRF.
Cosmic Ray Research Meeting in Mahidol university, Thailand.
Left row from front to back: Dr. Zhu Fengrong, Dr. Paisan Tooprakai, Fhon, Pierre-Simon, Alex and Dave Middle row: Kim Right row from front to back: Aey, Art, Bus, three international students from high school, Dr. Warit Mitthumsiri

Maggie and Quincy in Mainz, Germany

Quincy and I are over half way through with our European adventure. I can’t believe how quickly time has gone by. Centered in Mainz, Quincy and I are working with the IceCube group at the Johannes Gutenberg University.


My project focuses on the hardware aspects for a future part of the IceCube detector called PINGU. Searching for low energy atmospheric neutrinos, PINGU aims to determine the neutrino mass hierarchy. To design the new part of the detector, new optical modules to detect light, called Wavelength-Shifter Optical Modules (WOMs) are being studied. Unfortunately. The WOMS have an increase in noise at cooler temperatures. One hypothesis is that there is a decay of potassium in the glass creating photons, which creates a the signal noise. At colder temperatures, there are fewer vibrations in the WOM, making the photon more likely to successfully create a signal to be detected by the photomultiplier of the WOM.

Initially, I built a circuit with temperature probes to verify the temperature of the environment I am running my tests in. Now, I am attempting excite the glass of the WOMs using  ultraviolet light to observe whether or not there is more light at colder temperatures.


The Precision IceCube Next Generation Upgrade (PINGU) is designed primarily to detect low energy neutrinos on the order of about 1 GeV. Neutrinos at low energies are useful for resolving the Neutrino Mass Hierarchy (NMH), a prediction about mass differences between neutrino flavors. There are three neutrino flavors, and three mass states associated with these flavors. We know the difference in mass between two of the three neutrino mass states, but it’s unclear if the third mass states belongs below or above the two known mass states. We refer to these two mass state possibilities as normal NMH and inverted NMH.

I am working on producing cosmic ray flux simulations on the order of about 1 GeV. Neutrino flux on Earth appears to be isotropic on average, and this enables us to predict expected electron, muon and tau neutrino event rates at the IceCube detector. The first step is to generate a expected event rate, based on theory, as a function of cosine zenith angle and energy. Next, this theoretical event rate must be smeared to account for uncertainties in the detector hardware. I’m working on this smearing phase of the reconstruction.

We will produce two sets of simulated data which represent normal NMH and inverted NMH. When the PINGU detector hardware is installed and data are collected, we can compare the experimental results with these simulations. Over the course about 5 years of PINGU operation, we will be able to make a claim about the relative differences in neutrino mass states. We expect the experimental observation to align with either the normal NMH simulation or the inverted NMH simulation. This result will allow us to know the mass of each neutrino flavor, resolving one of the few remaining unknowns about relative particle mass in the standard model.

Dying from the heat…I was almost 40 C!
Quincy (left): Dying from the heat…It was almost 40 C!


The past weekend we spent exploring Munich. Attempting to escape the heat (the hottest weekend recorded in German history!) we spent our days jumping into a river running through the English Gardens, enjoying the Bavarian culture (think lederhosen…) and exploring the many museums Munich has to offer. We brought another summer student from America with us and met up with my friend from the University of Wisconsin-Madison, too. After a weekend well spent, we returned home for more fun in the lab!


Maggie and Quincy


Editor’s note: Maggie Beheler-Amass is an undergraduate at the University of Wisconson-Madison. Quincy Wofford III is an undergraduate at the University of Kansas. They are Mainz, Germany undertaking IceCube research under and NSF, IRES program at the University of Wisconsin-River Falls.