Shopping on line can be easy, simple and save you lots of money. It can also take a lot of your time, frustrate you, and result in unwanted purchases. Now the same can be said for regular high street shopping, but with the vast opportunity presented by the Internet it will pay you to spend a few minutes reading this and understanding how to better optimize your Alpha Emitter shopping experience:
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2. Research - if it has been said it will be on the internet. Ignorance is no longer a justifiable reason for buying the wrong thing. Take the time to research in detail everything that you could possible want to know about
3. Testimonials - don't know anybody that has bought a Alpha Emitter? Wrong! If the Alpha Emitter is good the internet will let you know. Use the Internet as a friend and get testimonials before you buy.
4. Questions - Got a question about Alpha Emitter then search the Forums, FAQ's, Blogs etc. Don't be afraid to ask .....
5. Reputation - Never heard of the company selling Alpha Emitter? Don't worry, no reason why you should know every company in the world, but you know someone that does! Use the internet to find out what people are saying about Alpha Emitter and build up a picture of their reputation for sales, returns, customer service, delivery etc.
6. Returns - still worried that even after all of the above your Alpha Emitter wont be what you want? Check out the returns policy. There is so much competition now that someone, somewhere is bound to offer the terms that you are comfortable with.
7. Feedback - happy with your Alpha Emitter then let people know, after all you are depending on others people input in your buying decision, so why not give a little back.
8. Security - check for the yellow padlock on the Alpha Emitter site before you buy, and the s after http:/ /i.e. https:// = a secure site
9. Contact - got a question about Alpha Emitter, or want to leave a comment then check out the sites contact page. Reputable companies have them and respond.
10. Payment - ready to pay for your Alpha Emitter, then use your credit card or PayPal! Be aware of companies that don't accept them, there may be genuine reasons but given the huge amount of choice you have when buying online there is no reason at all not to buy via credit card or PayPal.
nuclei and is readily stopped by a sheet of paper. Beta radiation, consisting of electrons, is halted by an aluminium plate. Gamma radiation is eventually absorbed as it penetrates a dense material.
Alpha particles (named after and denoted by the first letter in the
Greek alphabet, α) consist of two
protons and two
neutrons bound together into a particle identical to a
helium nucleus; hence, it can be written as He2+ or 42He. They are a highly ionizing radiation form of particle radiation, and have low penetration. The
alpha particle mass is 6.644656×10-27 kg, which is equivalent to the energy of 3.72738 gigaelectron volt. The charge of an alpha particle is equal to +2e, where e is the magnitude of charge on an electron, e=1.602176462x10-19C.
Alpha particles are emitted by
radioactive nuclei such as uranium or
radium in a process known as
alpha decay. This sometimes leaves the nucleus in an excited state, with the emission of a
gamma ray removing the excess
energy. In contrast to
beta decay, alpha decay is mediated by the strong nuclear force. Classically, alpha particles do not have enough energy to escape the potential of the nucleus. However, the Quantum tunneling effect allows them to escape.
When an alpha particle is emitted, the
atomic mass of an element goes down by roughly 4.0015 unified atomic mass unit, due to the loss of 2
neutrons and 2 protons. The
atomic number of the atom goes down by 2, as a result of the loss of 2 protons; the atom becomes a new element. An example of this is when radium becomes
radon gas due to alpha decay.
The energy of alpha particles varies, with higher energy alpha particles being emitted from larger nuclei, but most alpha particles have energies of between 3 and 7 MeV. This is a substantial amount of energy for a single particle, but their high mass means alpha particles have a lower speed (with a typical kinetic energy of 5 MeV the speed is 15,000 km/s) than any other common type of radiation (Beta particle, Gamma ray,
neutron radiation, etc). Because of their charge and large mass, alpha particles are easily absorbed by materials and can travel only a few centimeters in air. They can be absorbed by tissue paper or the outer layers of human skin (about 40 micrometres, equivalent to a few cells deep) and so are not generally dangerous to life unless the source is ingested or inhaled. Because of this high mass and strong absorption, however, if alpha radiation does enter the body (most often because radioactive material has been inhaled or ingested), it is the most destructive form of
ionizing radiation. It is the most strongly ionizing, and with large enough doses can cause any or all of the symptoms of radiation poisoning. It is estimated that chromosome damage from alpha particles is about 100 times greater than that caused by an equivalent amount of other radiation. The alpha emitter
polonium-210 is suspected of playing a role in lung cancer and
bladder cancer related to
tobacco smoking.
Most smoke detectors contain a small amount of the alpha emitter
americium#Isotopes. This isotope is extremely dangerous if inhaled or ingested, but the danger is minimal if the source is kept sealed. Many municipalities have established programs to collect and dispose of old smoke detectors, rather than let them go into the general waste stream.
Because alpha particles occur naturally, but can have
energy high enough to participate in a
nuclear reaction, study of them led to much early knowledge of nuclear physics. The physicist Ernest Rutherford famously used alpha particles to infer that
J. J. Thomson's Plum pudding model of the atom was fundamentally flawed. Rutherford's famous gold foil experiment was conducted by his students Hans Geiger and Ernest Marsden. A narrow beam of alpha particles was set up, passing through very thin (only a few hundred atoms thick) gold foil. The alpha particles were detected by a
zinc sulfide screen, which emits a flash of light upon an alpha particle collision. Rutherford hypothesisized that, assuming the "plum pudding" model of the atom was correct, the positively charged alpha particles would be only slightly deflected, if at all, by the dispersed positive charge predicted. It was found that some of the alpha particles were deflected at much larger angles than expected, with some even bouncing back. Although most of the alpha particles went straight through as expected, Rutherford commented that the few particles that were deflected was akin to shooting a fifteen inch shell at tissue paper only to have it bounce off, again assuming the "plum pudding" theory was correct. It was soon determined that the positive charge of the atom was concentrated in a small area in the center of the atom, hence making the positive charge dense enough to deflect any positively charged alpha particles that happened to come close to what was later termed the nucleus (it was not known at the time that alpha particles were themselves nuclei nor was the existence of protons or neutrons known). Rutherford's experiment subsequently led to the
Niels Bohr Bohr model and later the modern wave-mechanical model of the atom.
Rutherford's work also improved on previous measurements of the ratio of an alpha particle's mass to charge, allowing him to deduce that alpha particles were helium nuclei.
In computer technology, Dynamic random access memory 'soft errors' were linked to alpha particles in 1978 in
Intel's DRAM chips. The discovery led to strict control of radioactive elements in the packaging of semiconductor materials, and the problem was largely considered 'solved'.
See also
References
nuclei and is readily stopped by a sheet of paper. Beta radiation, consisting of
electrons, is halted by an aluminium plate. Gamma radiation is eventually absorbed as it penetrates a dense material.
Alpha particles (named after and denoted by the first letter in the
Greek alphabet, α) consist of two protons and two
neutrons bound together into a particle identical to a helium nucleus; hence, it can be written as He2+ or 42He. They are a highly
ionizing radiation form of
particle radiation, and have low penetration. The alpha particle mass is 6.644656×10-27 kg, which is equivalent to the energy of 3.72738 giga
electron volt. The charge of an alpha particle is equal to +2e, where e is the magnitude of charge on an electron, e=1.602176462x10-19C.
Alpha particles are emitted by
radioactive nuclei such as
uranium or radium in a process known as
alpha decay. This sometimes leaves the nucleus in an excited state, with the emission of a gamma ray removing the excess
energy. In contrast to
beta decay, alpha decay is mediated by the strong nuclear force. Classically, alpha particles do not have enough energy to escape the potential of the nucleus. However, the
Quantum tunneling effect allows them to escape.
When an alpha particle is emitted, the atomic mass of an element goes down by roughly 4.0015
unified atomic mass unit, due to the loss of 2
neutrons and 2 protons. The atomic number of the atom goes down by 2, as a result of the loss of 2 protons; the atom becomes a new element. An example of this is when radium becomes radon gas due to alpha decay.
The energy of alpha particles varies, with higher energy alpha particles being emitted from larger nuclei, but most alpha particles have energies of between 3 and 7 MeV. This is a substantial amount of energy for a single particle, but their high mass means alpha particles have a lower speed (with a typical kinetic energy of 5 MeV the speed is 15,000 km/s) than any other common type of radiation (
Beta particle,
Gamma ray,
neutron radiation, etc). Because of their charge and large mass, alpha particles are easily absorbed by materials and can travel only a few centimeters in air. They can be absorbed by tissue paper or the outer layers of human skin (about 40 micrometres, equivalent to a few cells deep) and so are not generally dangerous to life unless the source is ingested or inhaled. Because of this high mass and strong absorption, however, if alpha radiation does enter the body (most often because radioactive material has been inhaled or ingested), it is the most destructive form of
ionizing radiation. It is the most strongly ionizing, and with large enough doses can cause any or all of the symptoms of radiation poisoning. It is estimated that chromosome damage from alpha particles is about 100 times greater than that caused by an equivalent amount of other radiation. The alpha emitter
polonium-210 is suspected of playing a role in lung cancer and
bladder cancer related to tobacco smoking.
Most smoke detectors contain a small amount of the alpha emitter americium#Isotopes. This isotope is extremely dangerous if inhaled or ingested, but the danger is minimal if the source is kept sealed. Many municipalities have established programs to collect and dispose of old smoke detectors, rather than let them go into the general waste stream.
Because alpha particles occur naturally, but can have energy high enough to participate in a
nuclear reaction, study of them led to much early knowledge of nuclear physics. The physicist
Ernest Rutherford famously used alpha particles to infer that
J. J. Thomson's Plum pudding model of the atom was fundamentally flawed. Rutherford's famous gold foil experiment was conducted by his students Hans Geiger and Ernest Marsden. A narrow beam of alpha particles was set up, passing through very thin (only a few hundred atoms thick) gold foil. The alpha particles were detected by a zinc sulfide screen, which emits a flash of light upon an alpha particle collision. Rutherford hypothesisized that, assuming the "plum pudding" model of the atom was correct, the positively charged alpha particles would be only slightly deflected, if at all, by the dispersed positive charge predicted. It was found that some of the alpha particles were deflected at much larger angles than expected, with some even bouncing back. Although most of the alpha particles went straight through as expected, Rutherford commented that the few particles that were deflected was akin to shooting a fifteen inch shell at tissue paper only to have it bounce off, again assuming the "plum pudding" theory was correct. It was soon determined that the positive charge of the atom was concentrated in a small area in the center of the atom, hence making the positive charge dense enough to deflect any positively charged alpha particles that happened to come close to what was later termed the nucleus (it was not known at the time that alpha particles were themselves nuclei nor was the existence of protons or neutrons known). Rutherford's experiment subsequently led to the Niels Bohr
Bohr model and later the modern wave-mechanical model of the atom.
Rutherford's work also improved on previous measurements of the ratio of an alpha particle's mass to charge, allowing him to deduce that alpha particles were helium nuclei.
In computer technology, Dynamic random access memory 'soft errors' were linked to alpha particles in 1978 in Intel's DRAM chips. The discovery led to strict control of radioactive elements in the packaging of semiconductor materials, and the problem was largely considered 'solved'.
See also
References
