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Advanced Practical Course M - Nuclear Physics

Registration and schedule management for Practical Course M is possible via the central internship database.

For participation in the experiments on nuclear physics in the Nuclear Physics Practical Course, attendance at the introductory meeting and the radiation protection instruction is mandatory. The last attended instruction must not be longer than 12 months ago, otherwise, repetition is required. As it is currently not possible to hold classroom lectures, it is not yet possible to specify a date for the next instruction for the summer semester of 2021. As soon as a date can be set, it will be published here.

You can select the four experiments you want to participate in from the list of experiments. Please send your request to Dr. Christoph Fransen. We will try to take your preferences into account. If we do not receive a request, we will schedule four randomly selected experiments for you.

Experiments on nuclear physics in the Advanced Practical Course M will only take place on fixed dates on Monday and Thursday during the lecture period for reasons of radiation protection. Note: Most experiments will be scheduled normally, however some might require you to contact your tutor. These experiments will appear with a date in the past or at night (23:00) in the database.

M3.1: Dosimetry

Radiation protection is a preliminary to any exposure to ionizing radiation. The so-called ALARA radiation safety principle is based on the minimization of radiation doses which can be achieved while working with, e.g., radioactive samples. The three major principles to assist with maintaining doses “As Low As Reasonably Achievable” are time, distance, and shielding.

In the first part of the experiment the interrelation of activity, energy dose, and energy-dose rate, as well as their dependence on time and distance, are studied for some γ-ray sources, using a Geiger-Müller counter. The effect of shielding on the radiation dose is the subject of the second part of the experiment. Attenuation coefficients of γ radiation in different materials are determined. Fundamentals on generation and decay of activated samples are treated in the third part of the experiment. Therefore, the decay curve of an excited energy state in the nuclide 116m1In, which has been activated by (n,γ) reactions, is measured.

Downloads

Instructions M3.1: Dosimetry
(PDF)

Location

Institute for Nuclear Physics, Room 106

Tutor

M3.2: Cosmic Radiation

In this experiment, cosmic rays are detected by a telescope consisting of two plastic scintillators. The intensity of the cosmic rays is analyzed for its dependence on the zenith angle, caused by the earth's magnetic field, i.e., the so-called east-west effect. To enable measurement of this effect, the two scintillators are mounted on a rotatable frame and are operated in a coincidence circuit. The experiment focuses on important characteristics of cosmic rays and the earth's magnetic field as well as on a technically demanding setup.

Location

Institute for Nuclear Physics, Room 402

Tutor

M3.3: Rutherford Scattering

In this experiment, the famous experiment of Rutherford, Geiger, and Marsden, which lead to the development of the nuclear model, is reproduced. Therefore, α particles emitted by a radioactive source are scattered on a thin foil made of gold, before they are detected in a silicon detector. The refined measurement setup, invented by Chadwick, allows for a measurement of the angular distribution of the scattered α particles with up to five data points on a single day. Pulse-height spectra are recorded for different scattering angles. After integration of the spectra - and following transformation into the center-of-mass system - the measured intensities are converted into absolute cross-sections.

Location

Institute for Nuclear Physics, Room 107

Tutor

M3.4: β Scintillation

This experiment addresses the properties of the β decay, that led to the postulation of the neutrino by Wolfgang Pauli in 1930. Energy spectra of electrons from the β decay of 207Bi and 137Cs are measured using a scintillation detector. The (continuous) energy spectrum of the electrons and the corresponding Kurie plot are compared to the theoretically expected distribution. Contributions coming from conversion electrons of coincident γ decays have to be taken into account.

Location

Institute for Nuclear Physics, Room 107

Tutor

M3.5: Anti-Compton Spectroscopy

This experiment is an advanced version of the experiment "B3.2: γ-ray spectroscopy" (Practical Course B). Differences between a NaI scintillator and a high-purity semiconductor detector are investigated. Moreover, using different detectors for veto signals, Compton suppression is studied for various positions of a radioactive source, investigating the resulting γ-ray energy spectra. The suppression of Compton-scattered γ rays is key for Anti-Compton spectroscopy and its application in modern γ-ray spectroscopy. Evaluation of the characteristics of the experimental setup is completed by studying an "unknown" γ-ray source.

Location

Institute for Nuclear Physics, Room 112

Tutor

M3.6: Lifetime Measurements

The lifetimes of nuclear excited states are important observables in nuclear physics. Their precise measurement is of key importance for developing and testing nuclear models as they are directly linked with the wave functions of the nuclear system. For lifetimes from the μs region down to the ps region, the electronic fast-timing technique is most widely used. This technique provides a direct lifetime measurement through time-difference measurements between the γ rays which feed and decay from an excited state. Very fast CeBr3 scintillation detectors with good energy resolution will be used to detect and select the γ rays. The analog energy signals of the detectors are connected to a digital acquisition system for a real-time digital pulse-shape analysis. The data are acquired in a time-ordered list-mode format for coincidence analyses, such as the generation of γ-γ time-difference spectra. The lifetimes of the first excited 2+ states in 152Gd and 152Sm, produced in the decay of 152Eu, will be measured. This experiment also provides insight into modern digital data-acquisition systems, which make it possible to perform complex experiments, as actually done at the 10 MV tandem accelerator of the IKP.

Location

Institute for Nuclear Physics, Room 106

Tutor

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