Nuc Chem Final

multiple choice questions from exams

One of two nuclides with the same mass number and atomic number is called an

Isomer

The binding energy of a K electron in Ag is 26 keV. What is the energy of a conversion electron produced from this shell during IT decay of 113mAg

17keV

What nuclide is formed by decay of 130Te?

130Xe

Inside out NaI(Tl) detectors, gamma rays are most likely to interact with

I-

Which modes of decay are known for 78Cu?

Beta (minus), delayed particle emission, and beta + neutron

After undergoing compton scattering, a gamma photon

is lower in energy and changes direction

True or false: A plot of gamma ray energy vs. percent efficiency is linear

false

True or false: Double escape peaks are only oberserved when E0 > 1.022 MeV

True

an electron interacts with the outer shell electron of another nuclide which causes it to “brake” and change direction. This brake and change in direction emit a characteristic x-ray

compton scatter

When a gamma ray interacts with something like a crystal or another nuclide and the interaction produces light and an electron

photoelectric effect

when two nuclides interact and two electron and a positron are produced

pair production

Why is an iodine escape peak always much less intense than its corresponding photopeak?

the interaction with the iodine in the crystal is not as significant as the one that produces the photopeak

Beta (B-) particles are:

Ionizing radiation, emitted by an unstable nucleus, high-speed electrons

A quark is a(n):

part of a nucleon and sub-atomic particle

The strong force:

holds nuclei together, acts between nucleons, is stronger than coulomb repulsion, and works only over very short distances

What does the following define: “A nucleus with any number of protons and neutrons.”

nuclide

____ decay occurs when a proton changes to a neutron in the nucleus of an atom

positron and EC

Black coloring in the top half of a square in Baum’s square chart means that nuclide

is naturally occurring and is stable or has a really long half-life

____ equilibrium occurs when the half-life of the parent is shorter than that of its daughter, and the time of observation is long relative to the half-life of the parent

No

GM tubes

Have a resolving time of about 400us, do not record energy of beta, and detect primarily from ionizations

True or false: Exposure to radiation always (eventually results in cancer

False

True or false: If a nuclide does not contain magic numbers of nucleons, it is certain to be unstable

False

Isotone

two nuclides that have the same number of neutrons and different number of protons

Specific activity

Activity per unit mass of a substance (Bq/kg) also the rate of radioactive decay per unit mass of the sample

True or false: branch ratio does not affect true half-life

True

Which are likely unstable toward fusion?

3H and 22Ne

Alpha particles

have 2+ charge, are more likely emitted by heavy nuclides, interact strongly with matter, and are monoenergetic

Electron capture

can occur when N/Z is low ad is more likely with high Z nuclides

Which of the following are examples of isobaric decay?

Beta, positron, EC

Efficiency of radiation detection by GM tubes

decreases with distance, depends on the energy of the beta particle, and is generally lower for gamme, compared to beta

The difference is mass between the actual atomic mass and the mass calculated by adding up the rest masses of its protons, neutrons and electrons is

known as the mass defect, used to calculate nuclear binding energy, almost always larger for heavier nuclides

What is the energy of the most commonly observed gamma photonin the beta decay of 193Os?

138.9keV

What nuclide is formed by positron decay of 58Co?

58Fe

Why is an antineutrino produced with every B- decay?

conservation of energy, conservation of particles, conservation of angular momentum

True or false: A count rate from a single one-minute count has the same precision as the mean count rate from 20 one-minute (same sample, same geometry)

False

True or false: Electron capture requires 1.022MeV minimum energy to happen

False

What is the third dimension to the chart of the nuclides

energy (or mass)