Study of energy loss and track formation with Mica
Workshop,Cutting Edge Technology for Understanding the Earth
January 12, 2023

Yuki Ido, Tatsuhiro Naka
Toho University, Particle Physics Laboratory

1.Introduction

Matter particle Gauge boson Higgs boson

ElectronParticles that constitute matter

Particles that carries force A particles that gives mass

QUARKS

1.1 The Dark Matter

PhotonProtonmoleculeHiggs

QUARKwater

2.1 The difference in the dominant energy loss
mechanism might effect the track formation

Gluon
LEPTONS

OxygenParticle physics has now completed theAtom
Standard Model which describes the worldof particles smaller than atoms. However,from astronomical observation, it is now
known that the particles that we know only
consists about 5% of the universe.
This is one of the gratest mystries of particle
physics.

Z boson
Neutron

QUARK

W bosonElementary particles

2.Research Agenda

The difference in how thealpha recoil and fission tracks
are seen might be attributed
to the difference in thedominant stopping power.

Physics-Uspekhi, Volume 60, Issue 1, pp. 3 (2017)

1.2 Stellar Archaeology

シミュレーション：馬場淳一 可視化：中山弘敬 国立天文台4次元デジタル宇宙プロジェクトhttps://www.nao.ac.jp/contents/news/science/2022/20220909-cfca-fig-full.png

1.3 Paleo-Detector

Fission track

Paleo-Detector is a detector
with proven results inGeoscience.

Fission track madeby Th with β＝8.0×10-4
The Nuclear stopping power(Nsp) is dominant

EnergyVelocity（β= v/c）
Electronic stopping power[MeV/(mg/cm^2)]
Nuclear stopping power[MeV/(mg/cm^2)]

Nuclear stopping power isdominant for the Q-ball.
Therefore, it is necessary toverify the threshold of trackformation for Electronic
stopping power(Esp) andNuclear stopping power(Nsp).

Stellar Archaeology is a section of astronomy
which discusses how the galaxies form and evolve.
Compared to convetional methods, this study has
a potential to give completely different
information to Stellar Archaeology.

Alpha recoil track

Fission track madeby Kr with β＝5.1×10-2
The Electronic stopping power(Esp) is dominant

Th70keV
8.0 E-4

Kr
100MeV
5.1 E-2

1.41E+00

4.097E+01

1.21E+01

1.268E-01

3.Method

HF25umwater

Paleo-Detector

XENON1T Detector

10mg-100g

1-10 tonTarget mass
Integration time1 Gyr

10yr

Exposure

0.01-100kg×Myr

0.001-0.01kg×Myr

water

Etching data
Etching liquid：HF 46％
Tempereture：25℃

Exposure data
Nuclide：FeEnergy：500MeV/n

4.Resultsmica

Can we apply this technique to Particle Physics?

mica

Fe 500MeV/n

4.2 Analysis of optical microscope image

Images of tracks using a microscope.

①

②

②

①

The luminance of the end was confirmed.
The dE/dx should be bigger for Alpharecoil tracks.
Is the phase difference in effect?

Sample of EC80min using a Phase contrast microscope with a 60-power object lens.

4.3 Analysis by AFM

4.1 Determining the energy threshold
The length of tracks before etching is𝑙origin = 𝑙Experimental value × 2𝑣𝐸𝐶 𝑡𝐸𝐶

AFM image of EC60min

AFM image of EC40min

AFM image of EC20min𝑙origin ：original length 𝑙Experimental value：length observed by microscope𝑣𝐸𝐶 ：etching speed𝑡𝐸𝐶 ：etching time

Determine the energy threshold by comparing the 𝑙origin to simulation

As the etching time gets longer thewidth of each track is wider.
Measurements show that the etching
speed was 1.0 um/h and the exposure
angle was an average of 2.6 degrees.

149.80um
13.8MeV/mg/cm2

Reference：Uranium α recoil tracks are 13.5 [MeV/mg/cm^2]

What are ideal minerals?
・Few back ground Uranium
・Easy to work with (like mica)
・Extract from deeper mantle
・As old as possible (Couple hundred million years)?

沖縄県立博物館
https://okimu.jp/sp/ganseki/rotou/626:ganseki:1/

5.Prospects

・Further verification of the difference in track formation for Nsp and Esp,
determine the threshold・lower energy・exposing the sample vertically ・heavier particles

・Large scale scan using a scanning system→Updating Q-ball search region
・Application for searching other unknown particles using different minerals
・Expanding new research methods for Stellar Archaeology and Historical Geology