Radioactivity refers to the particles which are emitted from nuclei as a result of nuclear instability. Because the nucleus experiences the intense conflict between the two strongest forces in nature, it should not be surprising that there are many nuclear isotopes which are unstable and emit some kind of radiation.
Detection of Radioactivity
Characteristics of the Three Types of Emission
Nuclear Reactions
Half-Life
Uses of Radioactive Isotopes Including Safety Precautions
Radioactivity refers to the particles which are emitted from nuclei as a result of nuclear instability. Because the nucleus experiences the intense conflict between the two strongest forces in nature, it should not be surprising that there are many nuclear isotopes which are unstable and emit some kind of radiation.
Detection of Radioactivity
Characteristics of the Three Types of Emission
Nuclear Reactions
Half-Life
Uses of Radioactive Isotopes Including Safety Precautions
radioactivity is the act of emitting radiation spontaneously. This is done by an atomic nucleus that, for some reason, is unstable; it "wants" to give up some energy in order to shift to a more stable configuration.
radioactivity is the act of emitting radiation spontaneously. This is done by an atomic nucleus that, for some reason, is unstable; it "wants" to give up some energy in order to shift to a more stable configuration.
Pharmaceutical Inorganic chemistry UNIT-V Radiopharmaceutical.pptx
Isotopes Types of decay
Alpha rays, which could barely penetrate a piece of paper
Beta rays, which could penetrate 3 mm of aluminium
Gamma rays, which could penetrate several centimetres of lead
Units of Radioactivity:
Measurement of Radioactivity
The measurement of nuclear radiation and detection is an important aspect in the identification of type of radiations (, , ) and to assay the radionuclide emitting the radiation, suitable detectors are required. The radiations are identified on the basis of their properties.
e.g. Ionization effect is measured in Ionization Chamber, Proportional Counter and Geiger Muller Counter.
The scintillation effect of radiation is measured using scintillation detector and the photographic effect is measured by Autoradiography.
Gas Filled Detectors:
Ionization Chamber:
Proportional Counters:
Geiger-Muller Counter
Properties of α, β, γ radiations
Half –life of Radioelement
Sodium Iodide (I131)
Handling and Storage of Radioactive Material:
Storage of Radioactive Substances –
Precautions For Handling Radioactive Substances
Labelling of Radioactive Substances
Pharmaceutical Application Of Radioactive Substances
it covers types of counter for measurem,ent of radioactive substances also cover about radioactivity its causes effects and types of radioactive pollution
radiopharmaceuticals introduction isotopes types of radioisotopes measurement of radioactivity handling and storage of radioactive material applications
gm counter .working principle of gm counter, construction, advantage and disadvantage of gm counter.
Scintillation counter, its history, solid and liquid scintillation, scintillation cocktail, photomultiplier tube, advantage, and disadvantage.
An isotope is one of two or more atoms having the same atomic number but different mass numbers.
Unstable isotopes are called Radioisotopes.
uses of radioisotopes are many which are discussed in this slide.
The increased availability of biomedical data, particularly in the public domain, offers the opportunity to better understand human health and to develop effective therapeutics for a wide range of unmet medical needs. However, data scientists remain stymied by the fact that data remain hard to find and to productively reuse because data and their metadata i) are wholly inaccessible, ii) are in non-standard or incompatible representations, iii) do not conform to community standards, and iv) have unclear or highly restricted terms and conditions that preclude legitimate reuse. These limitations require a rethink on data can be made machine and AI-ready - the key motivation behind the FAIR Guiding Principles. Concurrently, while recent efforts have explored the use of deep learning to fuse disparate data into predictive models for a wide range of biomedical applications, these models often fail even when the correct answer is already known, and fail to explain individual predictions in terms that data scientists can appreciate. These limitations suggest that new methods to produce practical artificial intelligence are still needed.
In this talk, I will discuss our work in (1) building an integrative knowledge infrastructure to prepare FAIR and "AI-ready" data and services along with (2) neurosymbolic AI methods to improve the quality of predictions and to generate plausible explanations. Attention is given to standards, platforms, and methods to wrangle knowledge into simple, but effective semantic and latent representations, and to make these available into standards-compliant and discoverable interfaces that can be used in model building, validation, and explanation. Our work, and those of others in the field, creates a baseline for building trustworthy and easy to deploy AI models in biomedicine.
Bio
Dr. Michel Dumontier is the Distinguished Professor of Data Science at Maastricht University, founder and executive director of the Institute of Data Science, and co-founder of the FAIR (Findable, Accessible, Interoperable and Reusable) data principles. His research explores socio-technological approaches for responsible discovery science, which includes collaborative multi-modal knowledge graphs, privacy-preserving distributed data mining, and AI methods for drug discovery and personalized medicine. His work is supported through the Dutch National Research Agenda, the Netherlands Organisation for Scientific Research, Horizon Europe, the European Open Science Cloud, the US National Institutes of Health, and a Marie-Curie Innovative Training Network. He is the editor-in-chief for the journal Data Science and is internationally recognized for his contributions in bioinformatics, biomedical informatics, and semantic technologies including ontologies and linked data.
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
3. RADIOACTIVITY
It refers to the radiations or particles which are emitted from
nuclei as a result of nuclear instability.
These radiations are generally emitted from heavy metals like:
uranium , thorium , radium , etc.
The substances that emits such radiations are called
RADIOACTIVE SUBSTANCE.
The phenomenol of spontaneous and continuous emition of
such radiations is called RADIOACTIVITY.
4. PROPERTIES OF
RADIOACTIVITY
These radiations can penetrate through solid material , can ionize
the gases , produce a glow on zinc sulphide[ZnSO4] paint or affect
the photographic plates.
These radiations are emitted without any external agencies.
These are independent of temperature , pressure ,
concentration , or catalyst.
5. TYPES OF RADIATIONS
The radiations emitted by the radioactive isotopes is in the
form of charged particles i.e. ALPHA RAYS AND BETA
RAYS[alpha is positively charged and beta is negatively
charged]
There are some uncharged particles also that are called
GAMMA RAYS .
6. MEASUREMENT OF
RADIOACTIVITY
To measure the radiations of alpha beta and gamma rays
many techniques involving DETECTION and COUNTING
OF INDIVIDUAL PARTICLES , PHOTONS have been
available.
The method selected for the measurement of radioactivity
depends upon the “extent of energy dissipation and
penetrability of radiation.”
7. MEASUREMENT OF
RADIOACTIVITY
For measurement of radioactivity many devices are used. Some are
listed below:
IONIZATION CHAMBER
PROPORTIONAL CHAMBER
SCINTILLATION COUNTER
GEIGER-MULLER COUNTER
SEMICONDUCTOR DETECTORS
PHOTOGRAPHIC PLATE METHOD
9. IONIZATION CHAMBER
These are of various shapes and sizes.
A chamber is filled with GAS and is fitted with TWO
ELECTRODES kept a different potentials .
It is connected to a measuring device to indicate the FLOW OF
ELECTRIC CURRENT.
The filled gas can be He , Ar , etc.
They have poor resolution due to large number of chrge carriers.
10. PRINCIPLE:
The radiation causes ionization of gas molecules or produce
ions which result in the emission of electrons.
This shows change in electric current which is measured
with measuring device.
The current produced is of 10-15 ampere.
12. PROPORTIONAL
COUNTER
The proportional counter is a type of gaseous ionization detector
device used to measure particles of ionizing radiation.
The key feature is its ability to measure the energy of incident
radiation, by producing a detector output that is proportional to the
radiation energy; hence the detector's name.
14. SCINTILLATION
COUNTER
A scintillation counter is an instrument for detecting and
measuring ionizing radiation by using the excitation effect of
incident radiation on a scintillator material, and detecting the
resultant light pulses.
The counter consists of a scintillation crystal coupled with
PHOTOMULTIPLIER TUBE , an AMPLIFIER and a SCALER.
15. PRINCIPLE
When ionizing radiation strikes certain substances like
phosphorous [or a flurogenic materials] a flash of light is given
out .
The flash is collected by a photomultiplier tube which
produces electric impulse.
This impulse , on further amplification , is recorded by
means of a scaler.
16. TWO MAIN TYPES:
INORGANIC SCINTILLATOR[ SODIUM IODIDE]:
This is for gamma rays.
ORGANIC SCINTILLATOR
This is for alpha and beta rays.
17. GEIGER COUNTERS
The Geiger counter is an instrument used for
measuring ionizing radiation used widely in applications such
as radiation dosimetry , radiological protection, experimental
physics and the nuclear industry.
This is commomly known as GEIGER MULLER[GM] and is
the best of all radiation detectors.
They can detect all the three types of radiations [ alpha , beta
and gamma]
18. CONSTRUCTION
A Geiger counter consists of a
Geiger-Müller tube, the sensing
element which detects the radiation
and the processing electronics
which displays the result.
19. PRINCIPLE
The Geiger-Müller tube is filled with an inert gas such as helium, neon,
or argon at low pressure, to which a high voltage is applied. The tube briefly
conducts electrical charge when a particle or photon of incident radiation makes
the gas conductive by ionization. The ionization is considerably amplified within
the tube by the Townsend discharge effect to produce an easily measured
detection pulse, which is fed to the processing and display electronics. This large
pulse from the tube makes the G-M counter relatively cheap to manufacture, as
the subsequent electronics is greatly simplified.[2] The electronics also generates
the high voltage, typically 400–600 volts, that has to be applied to the Geiger-
Müller tube to enable its operation.
20. SEMICONDUCTOR
DETECTOR
They are useful in measuring X-rays and Gamma rays.
In this, charge carriers produced by ionizing radiation are
electron-hole pairs.
These travel towards the positive electrodes with high
velocities.
21. PHOTOGRAPHIC PLATE
METHOD
An ionizing particle causes an activation and darkening of a
photographic plate.
The degree of darkening gives the measure of the total
activity.
This method is used to locate the exact distribution of
radioactive material in a thin section.
This method is mainly detect the GAMMA Rays.
