1 Mössbauer Effect J-H. Kim

2 Motivation - Beginning - Beginning - Mössbauer Effect(Ir-191) - Mössbauer Effect(Ir-191)Experiment - Mössbauer Measurements - Mössbauer MeasurementsSummary Contents

3 Before the Mössbauer theory What is the Mössbauer effect ? I am a nuclei excited state. I am a nuclei at ground state. I want to go to the excited state. You will be unstable. Do you want it? Ok. I will give you a gamma ray for your exciting. Thank you! This energy is not enough for my exciting. The energy of my gamma should be smaller than excited since I should be recoiled. MotivationApplications Summary Yes~!

4 Before the Mössbauer theory. What is the Mössbauer effect ? - The nuclei recoil back with velocity v(βc). - The frequency of gamma ray for absorption is lower than at the emission. => Then target nuclei cannot absorb the gamma energy. # For Ir-191 (hν = 129 keV) v = 202 m/s E’ = keV ΔE= 8.71E-5 keV Γ = 3.22E-8 keV (natural line width) ΔE ≫ Γ Momentum conservation. Doppler effect. MotivationApplications Summary

5 Beginning - Rudolf Mössbauer.(1929~?, German physicist) - Rudolf Mössbauer.(1929~?, German physicist) - Discovered the recoil-free emission and absorption of gamma rays by nuclei. (in 1958) - Discovered the recoil-free emission and absorption of gamma rays by nuclei. (in 1958) - Win the Novel prize. (in 1962) - Win the Novel prize. (in 1962) Experiment ( Recoil Free Nuclear Radiation ) - Ir Ir-191 How atom can recoil-free emission and absorption? - Atoms are held tightly in crystalline atomic structures - Atoms are held tightly in crystalline atomic structures What is the Mössbauer effect ? MotivationApplications Summary

6 Beginning with the Mössbauer theory What is the Mössbauer effect ? I am a nuclei excited state. Really? but.. I don’t believe you. -_-;; Really? I believe you then. I am a nuclei at ground state. I can give you an energy for your exciting. I am K-U.Choi nuclei. I have a different flavor than yours. MotivationApplications Summary K-U.Choi stick me on this space with silicon! so I can have little momentum.

7 Beginning with the Mössbauer theory. What is the Mössbauer effect ? - We don’t know the share the required momentum. - I calculate the number of nuclei for the condition. ΔE<Γ (ΔE=E_pt-E_pt’) # For Ir-191 (hν = 129 keV) N=2700, v = 7.5 cm/s, E’ = … keV - N ≪ 1 mol(10E23) =>velocity and energy loss is very small. # For Ir-191 (hν = 129 keV), N = 1mol v = 2E-19 cm/s ≒ 0 cm/s MotivationApplications Summary

8 Intensity Velocity 0 ΔE 0 Measurement for Mössbauer effect. How to measure the M össbauer effect. Source. Absorber. Detector. Equipment Data MotivationApplications Summary

9 What can we measure with Mössbauer effect? Applications. 1. The lifetime determinant for an excited particle. 1. The lifetime determinant for an excited particle. 2. Nuclei energy level. 2. Nuclei energy level. 3. The general relativity theory. 3. The general relativity theory. - Gravitational red shift. - Gravitational red shift. 4. The hyperfine structure. 4. The hyperfine structure. - The nuclear isomer shift. - The nuclear isomer shift. - The nuclear Zeeman effect. - The nuclear Zeeman effect. - The nuclear quadrupole splitting. - The nuclear quadrupole splitting. MotivationApplications Summary

10 Particle lifetime of an excited state in a nucleus. 1. The lifetime determinant for an excited particle. - τ=Δt : particle lifetime. - τ=Δt : particle lifetime. - ΔE(Γ/2) : can be determined in Mössbauer experiment. - ΔE(Γ/2) : can be determined in Mössbauer experiment. The Breit-Wigner distribution : The Breit-Wigner distribution : Γ : natural line width. Γ : natural line width. x axis : energy x axis : energy y axis : absorption cross section. y axis : absorption cross section. MotivationApplications Summary

11 Gravitational red shift. 2. The general relativity theory. - E_0 = hν = 14.4 keV - E_0 = hν = 14.4 keV - Gravitational red shift. - Gravitational red shift. ν=ν_0(1+(gh/c^2)) ν=ν_0(1+(gh/c^2)) ΔE=2*ν_0(gh/c^2) ΔE=2*ν_0(gh/c^2) MotivationApplications Summary ΔE

12 The nuclear isomer shift. 3. The hyperfine structure. MotivationApplications Summary The nuclear Zeeman effect. The nuclear quadrupole splitting.

13 3. The hyperfine structure. MotivationApplications Summary

14 What is the Mössbauer effect? Summary MotivationApplications Summary How to measure the Mössbauer effect. Applications 1. The lifetime determinant for an excited particle. 1. The lifetime determinant for an excited particle. 2. The general relativity theory. 2. The general relativity theory. 3. The hyperfine structure. 3. The hyperfine structure. 1. Gamma-ray source, an absorber, Gamma Detector. 1. Gamma-ray source, an absorber, Gamma Detector. 2. Relative velocity of varying the gamma-ray energy. 2. Relative velocity of varying the gamma-ray energy. For nuclei in crystalline atomic structures, the gamma radiation emitted from the nuclei are approximately recoil-free.

15 Thank you.