What is the gamma-ray energy of Caesium 137?
What is the gamma-ray energy of Caesium 137?
Cobalt-60 (60Co) and caesium-137 (137Cs) are the most widely used sources of gamma radiation. Co produces gamma rays with energies of 1.173 and 1.332 MeV and has a half-life of 5.27 years, whereas 137Cs produces gamma rays with an energy of 0.662 MeV and has a longer half-life of 30.1 years.
What is the principle of gamma rays?
In γ decay, the excited nucleon decays to a lower energy state and the energy difference is emitted as a quantized photon. Because nuclear energy levels are discrete, the transitions between energy levels are fixed for a given transition. The photon emitted from a nuclear transition is known as a γ-ray.
How does a gamma ray spectrometer work?
The Gamma Ray Spectrometer is known as the GRS. The spectrometer has mapped the amounts and types of chemical elements at or near Martian surface by measuring the way gamma rays from space change when they interact with different surface materials.
What is the specific activity of Cs-137?
Specific activity of Cs-137 is 3.2 10^12 Bq/g.
What is Caesium used for?
The most common use for caesium compounds is as a drilling fluid. They are also used to make special optical glass, as a catalyst promoter, in vacuum tubes and in radiation monitoring equipment. One of its most important uses is in the ‘caesium clock’ (atomic clock).
How does cesium-137 affect the environment?
How does cesium change in the environment? Cesium-137 decays in the environment by emitting beta particles. As noted above, cesium-137 decays to a short lived decay product, barium-137m. The latter isotope emits gamma radiation of moderate energy, which further decays to a stable form of barium.
What are 3 uses for gamma rays?
Uses of Gamma Rays:
- Sterilize medical equipment.
- Sterilize food (irradiated food)
- Used as tracers in medicine.
- Radio Therapy- In oncology, to kill cancerous cells.
- Gamma-Ray Astronomy.
Which detector is useful in gamma ray spectroscopy?
The thallium-activated sodium iodide detector, or NaI(Tl) detector, responds to the gamma ray by producing a small flash of light, or a scintillation. The scintillation occurs when scintillator electrons, excited by the energy of the photon, return to their ground state.
What are the most common detectors in gamma spectroscopy?
Common detector materials include sodium iodide (NaI) scintillation counters and high-purity germanium detectors. To accurately determine the energy of the gamma ray, it is advantageous if the photoelectric effect occurs, as it absorbs all of the energy of the incident ray.
Is cesium-137 naturally occurring?
Despite its prevalence in spent nuclear fuel and nuclear waste, cesium-137 is actually extremely rare. Its half-life is too short for it to persist from natural fission sources, and on earth it is a synthetic isotope only.
Why is Caesium so reactive?
Cesium has a large valence electron shell and a low effective nuclear charge. The size of the valence shell affects how tightly bound the outermost electrons are to the nucleus. Both of these factors make cesium extremely reactive.
What are the properties of Caesium?
It is silvery gold, soft, and ductile. It is the most electropositive and most alkaline element. Cesium, gallium, and mercury are the only three metals that are liquid at or around room temperature. Cesium reacts explosively with cold water, and reacts with ice at temperatures above -116°C.
What is the gamma spectrum for caesium 137?
137Cs gamma spectrum. The characteristic 662 keV peak does not originate directly from 137Cs, but from the decay of the daughter nuclide 137Ba from metastable to its stable state. Caesium-137 has a half-life of about 30.17 years.
Is Cesium 137 a radioactive element?
Cesium 137 (137 Cs, Cs137) is a radioactive isotope of the alkali metal cesium which is formed primarily as a by-product of nuclear fission. Cesium 137 undergoes beta (β−) decay and has half-life of about 30 years. Cesium 137 produces gamma emission at 662 KeV and 32 KeV. The screen shown below refers to the isotope Cesium 137.
What is the energy of de-excitation of 137 CS?
This de-excitation is accompanied by the emission of a gamma ray with the characteristic energy of 661.7 keV that we commonly use for gamma detector calibration. A total of 85.1% of all 137 Cs nuclei decay in this way (i.e. 85.1% of all 137 Cs nuclear decays result in 661.7 keV gamma rays).
What does the beta spectrum of 137 CS look like?
Fig. 2. Beta-spectrum of 137 Cs, adapted from this reference. The beta spectrum has two distinct features: a broad peak corresponding to the main decay mode of 137 Cs → 137m Ba with peak energy of 512 keV, which matches a trough on the spectrum centered around channel 3000, and
