Talk:Alpha decay

message: "Alpha decay is the most hazardous form of radiation," 
Gamma rays are more energetic, smaller, cross barriers better and are the most dangerous form of radioactivity from what I've read. No time to give references at the moment.--Voyajer 20:35, 19 January 2006 (UTC)
thread_title:  This is incorrect, please provide a reference

message: The article says: "Alpha decay is the most hazardous form of radiation". Alpha decay IS NOT a form of radiation, it is a kind of radioactive decay. The forms of radiation are alpha particles, beta particles, gamma and X-rays etc. --V1adis1av 18:31, 20 January 2006 (UTC)
thread_title:  Accuracy? 

message: Shouldn't the speed of alpha particles be in m/s not km/s also it should be stated as the velocity of alpha particles and not the 'speed' 23:22 26 November 2006
Good point; actually it should provide context, i.e. that typical velocity of emitted alpha particle is about 5% of the speed of light (Lachlan, 31/1/07).
*"speed" would actually be the correct term as "velocity" is defined as "speed" in a certain direction.  Starkrm 14:19, 28 March 2007 (UTC)
thread_title: Change to SI units

message: The article is kind of confusing in the sense that the top part says it is caused by the electromagnetic force, and lower down it says it's governed by the stong nuclear force. Could it be both? AstroHurricane001 00:03, 6 December 2006 (UTC)
thread_title:  What causes it 

message: I think it would be worth mentioning that (in general) a higher decay energy corresponds to a shorter half life while a lower decay energy corresponds to a longer half life. Again, not always true, but a little more detail in this article would be handy. Anyone agree? (Lachlan, 31/1/07). —The preceding unsigned comment was added by 128.250.54.27 (talk) 01:13, 31 January 2007 (UTC)
replies: text: Agreed hope to see that in the page as it is worth to study!HarryTian1999 (talk) 04:23, 5 April 2019 (UTC)
thread_title:  Energy vs Half life 

message: In the toxicity section, the first sentence does not make much sense and is false according to any decent radioactivity reference), and confuses the following statements. It has also been the cause of a lot of partial or false quotations above. I propose the following change to it (changes in caps):
"RADIOACTIVE NUCLEI THAT EMIT ALPHA PARTICLES are among the most hazardous SOURCES of radiation if these nuclei are incorporated within a human body. As any heavy charged particle, alpha particles lose their energy within a very short distance in dense media, causing significant damage to surrounding biomolecules. On the other hand, external alpha RADIATION is not harmful because alpha particles are completely absorbed by a very thin (micrometers) dead layer of skin as well as by a few centimeters of air. However, if a substance radiating alpha particles is ingested, inhaled by, injected into, or introduced through some skin-penetrating object (shrapnel, corrosive chemicals) into an organism it may become a risk, potentially inflicting very serious damage to the organism's genetic MATERIAL."
The main reason for confusion is that alpha-emitters typically also emit gamma radiation. More fact-checking and improvement for this page is definitely necessary. —The preceding unsigned comment was added by 129.2.40.128 (talk) 18:04, 1 February 2007 (UTC)
thread_title:  toxicity section correction proposed 

message: With IE 7 on the alpha decay site I see only the following:
"
Edie Denvir-"Generic blackman, please stop raping me every day at school"
Generic blackman-"No bitch, now suck my dick
"
But with firefox it shows the whole page?
Weird.
87.94.138.102 20:27, 1 February 2007 (UTC)
thread_title:  wikibug or something similar 

message: Do we need a proper explanation of the mechanism behind alpha decay, i.e. discussion of the potential barrier seen inside the nucleus and a quantum mechanical description of the tunneling event?  —Preceding unsigned comment added by Mattyp9999 (talk • contribs) 14:41, 22 February 2010 (UTC)
replies: text: Yes. The math is given in the WP article on the Geiger-Nuttall law, but we need the standard picture of the nuclear potential well, with sinusoidal waveforms on both sides with exponential decay of probability inside the barrier. SBHarris 14:45, 22 February 2010 (UTC)
thread_title:  Quantum Mechanics 

message: "The lightest known alpha emitter being the lightest isotopes (mass numbers 106–110) of tellurium (element 52)."  Wrong.  Beryllium-8 also undergoes alpha decay, that being one of the limiting factors of the triple-alpha process. Whoop whoop pull up Bitching Betty | Averted crashes 18:53, 28 July 2011 (UTC)
replies: text: Everything that produces fast helium nuclei, or alpha particles, doesn't qualify as "alpha decay." The fast alphas from ternary fission, for example, are not the same energy or mechanism as in traditional alpha decay, so this is not usually called alpha decay. In Be-8 what you really have is a sort of spontaneous fission that produces two alphas. But the mechanism is also quite different from what happens in heavier nuclei. SBHarris 19:38, 28 July 2011 (UTC)
replies: text: I think Whoop whoop pull up (almost six and a half years ago; sorry!) has a point here, though; neither mental picture, be it heavy nucleus-like α or heavy nucleus-like SF, fits 8Be terribly well, but it is usually considered an α decay in sources. Speaking in favour of that assignment is that fission fragments are quite variable and they are not in 8Be. Nonetheless, SBHarris is right to point out that this is not a "normal" α decay and should be treated as exceptional, with more normal examples of α decay such as 235U being preferable choices for illustration and understanding. Double sharp (talk) 06:50, 22 January 2018 (UTC)
replies: text: After the quoted words I have added (in August 2017) the sentence Exceptionally, however, beryllium-8 decays to two alpha particles. Dirac66 (talk) 11:51, 22 January 2018 (UTC)
thread_title:  Beryllium-8 

message: "An alpha particle is the same as a helium-4 nucleus, and both mass number and atomic number are the same."
Since the nucleon is 2 protons and 2 neutrons it would have a mass number of 4 and an atomic number of 2. 64.114.134.52 (talk) 04:17, 13 August 2011 (UTC)
replies: text: What was meant is that the mass number of the alpha is the same as that of a He-4 nucleus, and the atomic number of the alpha is the same as that of a He-4 nucleus. I will reword the text to make this clearer. Dirac66 (talk) 02:06, 14 August 2011 (UTC)
thread_title:  Mass Number != Atomic Number 

message: At the beggining of the article says "Alpha particles have a typical kinetic energy of 5 MeV (that is, ≈ 0.13% of their total energy, i.e. 110 TJ/kg) and a speed of 150,000,000,000 km/s. This corresponds to a speed of around 0.05 c." 
Speed of light is  299,792,458 metres per second according to the article about speed of light, there is an error of many orders of magnitude.  — Preceding unsigned comment added by 81.39.153.29 (talk) 10:49, 3 September 2011 (UTC)
replies: text: Fixed. Dauto (talk) 14:06, 3 September 2011 (UTC)
thread_title:  150,000,000,000 km/s? 

message: It is to be noted that an alpha decay transition of a nuclide does not change the (PN) category of the nucleus involved, since the resulting nucleus is of the same (PN) catogory. Therefor the reason for the change must be the occurrence of some kind of unbalance in the structure of the unstable atomic nucleus that can be improved by the shedding of 4 paired nuclei. This is reasoned to occur mostly due to the rising cumulative positive charge condition in the nucleus, which creates a greater force of repulsion on the paired protons of the structure. Then, if 2 of the paired protons can be combined into a helium nucleus configuration, the system can achieve a sufficient amount of free kinetic energy to exit the parent nucleus.WFPM (talk) 12:59, 28 March 2012 (UTC)
thread_title: Nuclear category transition

message: Add see __ for details.
I don't know if it is proper form, but adding the link to the usage section as an additional link to describe the household smoke detector. IF it does not appear to be useful, can be removed.
Richard416282 (talk)   — Preceding undated comment added 15:26, 26 September 2014 (UTC)
thread_title:  Uses - Americaranium241 

message: Hello fellow Wikipedians,
I have just modified  on Alpha decay. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
*Added archive http://web.archive.org/web/20090224200050/http://www.phy.uct.ac.za:80/courses/phy300w/np/ch1/node38.html to http://www.phy.uct.ac.za/courses/phy300w/np/ch1/node38.html
When you have finished reviewing my changes, please set the checked parameter below to true or failed to let others know (documentation at ).
Cheers.—cyberbot IITalk to my owner:Online 13:06, 3 July 2016 (UTC)
thread_title:  External links modified 

message: Hello fellow Wikipedians,
I have just modified  on Alpha decay. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
*Added archive http://web.archive.org/web/20090224200050/http://www.phy.uct.ac.za:80/courses/phy300w/np/ch1/node38.html to http://www.phy.uct.ac.za/courses/phy300w/np/ch1/node38.html
When you have finished reviewing my changes, please set the checked parameter below to true or failed to let others know (documentation at ).
Cheers.—cyberbot IITalk to my owner:Online 12:09, 6 July 2016 (UTC)
thread_title:  External links modified 

message: The article contained the following completely nonsensical text: "One curiosity is why alpha particles, helium nuclei, should be preferentially emitted as opposed to other particles like a single proton or neutron or other atomic nuclei.[note 1] Part of the answer comes from conservation of wave function symmetry, which prevents a particle from spontaneously changing from exhibiting Bose–Einstein statistics (if it had an even number of nucleons) to Fermi–Dirac statistics (if it had an odd number of nucleons) or vice versa. Single proton emission, or the emission of any particle with an odd number of nucleons would violate this conservation law." One way to see that this is nonsense is that proton emission does actually exist.--207.233.86.175 (talk) 16:02, 24 September 2019 (UTC)
thread_title: deleted nonsense about statistics

message: As nuclides get heavier, they are prone to undergo alpha decay. Here is a list of borders of nuclides that are alpha-stable, and the alpha decay energies (in keV) of nuclides with next many protons:
N  	Alpha-stable Z range	Nuclide with next many protons and its alpha decay energy (in keV)	Distance of alpha-stable isotones to beta-stability line
80 	Z ≤ 60              	141Pm: 229.8                                                      	0 (All beta-stable nuclides (except 5He and 8Be) with N ≤ 82 are alpha-stable)
81 	Z ≤ 61              	143Sm: 43.5                                                       	0 (All beta-stable nuclides (except 5He and 8Be) with N ≤ 82 are alpha-stable)
82 	Z ≤ 62              	145Eu: 99.4                                                       	0 (All beta-stable nuclides (except 5He and 8Be) with N ≤ 82 are alpha-stable)
83 	Z ≤ 58              	142Pr: 307.0                                                      	1
84 	Z ≤ 52 or Z = 54    	137I: 14.7, 139Cs: 664.0                                          	2
85 	Z ≤ 54              	140Cs: 26.8                                                       	3
86 	Z ≤ 56              	143La: 89.2                                                       	4
87 	Z ≤ 57              	145Ce: 200.1                                                      	5
88 	Z ≤ 58              	147Pr: 307.2                                                      	4
89 	Z ≤ 59              	149Nd: 294.1                                                      	5
90 	Z ≤ 61              	152Sm: 220.5                                                      	0 (150Nd)
91 	Z ≤ 63              	155Gd: 81.5                                                       	1
92 	Z ≤ 64              	157Tb: 178.0                                                      	0 (154Sm and 156Gd)
93 	Z ≤ 65              	159Dy: 478.7                                                      	0 (157Gd)
94 	Z ≤ 65              	160Dy: 437.3                                                      	0 (158Gd and 159Tb)
95 	Z ≤ 65              	161Dy: 342.8                                                      	1
96 	Z ≤ 65              	162Dy: 83.2                                                       	0 (160Gd)
97 	Z ≤ 66              	164Ho: 431.0                                                      	0 (163Dy)
98 	Z ≤ 66              	165Ho: 137.7                                                      	0 (164Dy)
99 	Z ≤ 66              	166Ho: 177.9                                                      	1
100	Z ≤ 67              	168Er: 551.9                                                      	2
101	Z ≤ 67              	169Er: 271.9                                                      	3
102	Z ≤ 67              	170Er: 51.2                                                       	4
103	Z ≤ 68              	172Tm: 257.8                                                      	1
104	Z ≤ 68              	173Tm: 119.9                                                      	2
105	Z ≤ 69              	175Yb: 597.2                                                      	3
106	Z ≤ 69              	176Yb: 566.8                                                      	4
107	Z ≤ 69              	177Yb: 242.7                                                      	5
108	Z ≤ 70              	179Lu: 823.2                                                      	2
109	Z ≤ 70              	180Lu: 267.1                                                      	3
110	Z ≤ 70              	181Lu: 304.4                                                      	4
111	Z ≤ 71              	183Hf: 928.5                                                      	5
112	Z ≤ 71              	184Hf: 481.3                                                      	6
113	Z ≤ 71              	185Hf: 304.4                                                      	7
114	Z ≤ 71              	186Hf: 43.5                                                       	8
115	Z ≤ 72              	188Ta: 62.1                                                       	7
116	Z ≤ 75              	192Os: 360.1                                                      	4
117	Z ≤ 76              	194Ir: 610.3                                                      	1
118	Z ≤ 76              	195Ir: 234.1                                                      	2
119	Z ≤ 77              	197Pt: 549.8                                                      	3
120	Z ≤ 77              	198Pt: 106.2                                                      	4
121	Z ≤ 79              	201Hg: 331.6                                                      	1
122	Z ≤ 79              	202Hg: 133.2                                                      	2
123	Z ≤ 80              	204Tl: 493.9                                                      	1
124	Z ≤ 80              	205Tl: 155.0                                                      	0 (204Hg)
125	Z ≤ 81              	207Pb: 392.3                                                      	1
126	Z ≤ 81              	208Pb: 517.0                                                      	2
127	Z ≤ 78              	206Au: 136.7                                                      	7
Continuation of this table according to this table: N = 128 isotones may be alpha-stable up to Z = 76 (204Os), with 205Ir having an alpha-decay energy of 0.59 MeV; the distance of alpha-stable isotones to beta-stability line is 12 (204Os to 192Os). N = 129 ~ 137 could have Z up to 76, 76, 76, 76, 76, 76, 77, 77, 77. Isotopes of Pb, Bi, Po, At may be alpha-stable from N = 144, 150, 154 and 158 (226Pb, 233Bi, 238Po, 243At) on. 2A04:CEC0:C027:CAB3:FDCA:A821:45D0:96B4 (talk) 15:12, 20 November 2023 (UTC)
thread_title:  Border of alpha-stable nuclides 

message: A common question is that why Po through Ac are so unstable compared to later elements Th through Cm. The following table may be used to give some intuition; the isotopes listed are all principally alpha emitters (the alpha decay branching ratio is 72.6% for 211Rn, 96% for 210Rn and >99.5% for the others). Notice the Geiger-Nuttall law.
Nuclide	Qα (MeV)	Nuclide	Qα (MeV)	Nuclide	Qα (MeV)
209Po  	4.97923 	208Po  	5.21530 	210Po  	5.40745
222Rn  	5.59031 	211Rn  	5.96538 	210Rn  	6.15891
226Ra  	4.87062 	223Ra  	5.97899 	224Ra  	5.78885
232Th  	4.08160 	230Th  	4.76996 	229Th  	5.16757
238U   	4.26795 	235U   	4.67826 	236U   	4.57310
244Pu  	4.66555 	242Pu  	4.98453 	239Pu  	5.24451
247Cm  	5.35348 	248Cm  	5.16173 	245Cm  	5.62300
251Cf  	6.17580 	249Cf  	6.29600 	250Cf  	6.12844
257Fm  	6.86355 	252Fm  	7.15270 	255Fm  	7.23972
The major decay modes for 225Ra (β−), 228Ra (β−), and 253Fm (88% EC) are not alpha decay, so these nuclides are not listed. 129.104.241.218 (talk) 14:34, 22 March 2024 (UTC)
thread_title:  Alpha decay energies of the most stable isotopes of even-''Z'' elements from Po to Fm 

message: Mass number	Isobar with the lowest energy	Atomic mass    	m(nuclide) - mass number×(m(4He)/4) (MeV)
1          	1H                           	1.007825031898 	6.68274
2          	2H                           	2.014101777844 	11.92326
3          	3He                          	3.016029321967 	13.11253
4          	4He                          	4.002603254130 	0
5          	5He                          	5.012057       	8.19988
6          	6Li                          	6.0151228874   	10.44951
7          	7Li                          	7.016003434    	10.66350
8          	8Be                          	8.00530510     	0.09184
9          	9Be                          	9.01218306     	5.89239
10         	10B                          	10.01685322    	9.63639
11         	11B                          	11.01143260    	3.98088
12         	12C                          	12             	-7.27475
13         	13C                          	13.003354835336	-4.75597
...        	...                          	...            	...
114        	114Sn                        	113.90278013   	-159.66984
115        	115Sn                        	114.903344696  	-159.75018
116        	116Sn                        	115.90174283   	-161.84853
117        	117Sn                        	116.9029540    	-161.32657
118        	118Sn                        	117.9016066    	-163.18789
119        	119Sn                        	118.9033113    	-162.20620
120        	120Sn                        	119.9022026    	-163.84518
121        	121Sb                        	120.9038157    	-162.94881
122        	122Te                        	121.9030439    	-164.27397
123        	123Sb                        	122.9042140    	-163.79026
124        	124Te                        	123.9028179    	-165.69694
125        	125Te                        	124.9044307    	-164.80086
126        	126Te                        	125.9033117    	-166.44943
127        	127I                         	126.904473     	-165.97392
128        	128Xe                        	127.9035313    	-167.45733
129        	129Xe                        	128.9047794    	-166.90096
130        	130Xe                        	0129.903508    	-168.69149
131        	131Xe                        	130.9050824    	-167.83118
132        	132Xe                        	131.9041535    	-169.30267
133        	133Cs                        	132.905451933  	-168.69942
134        	134Ba                        	133.90450825   	-170.18468
135        	135Ba                        	134.90568845   	-169.69156
136        	136Ba                        	135.90457580   	-171.33422
137        	137Ba                        	136.90582721   	-170.77477
138        	138Ba                        	137.9052471    	-171.92140
139        	139La                        	138.9063533    	-171.49717
140        	140Ce                        	139.9054387    	-172.95535
141        	141Pr                        	140.9076528    	-171.49916
142        	142Nd                        	141.9077233    	-172.03971
143        	143Nd                        	142.9098143    	-170.69819
144        	144Nd                        	143.9100873    	-171.05012
145        	145Nd                        	144.9125736    	-169.34038
146        	146Sm                        	145.913041     	-169.51122
147        	147Sm                        	146.9148979    	-168.38776
148        	148Sm                        	147.9148227    	-169.06404
149        	149Sm                        	148.9171847    	-167.47008
150        	150Sm                        	149.9172755    	-167.99173
151        	151Eu                        	150.9198502    	-166.19964
152        	152Sm                        	151.9197324    	-166.91560
153        	153Eu                        	152.9212303    	-166.12654
154        	154Gd                        	153.9208656    	-167.07249
155        	155Gd                        	154.9226220    	-166.04264
156        	156Gd                        	155.9221227    	-167.11396
157        	157Gd                        	156.9239601    	-166.00867
158        	158Gd                        	157.9241039    	-166.48095
159        	159Tb                        	158.9253468    	-165.92942
160        	160Dy                        	159.9251975    	-166.67472
161        	161Dy                        	160.9269334    	-165.66397
162        	162Dy                        	161.9267984    	-166.39595
163        	163Dy                        	162.9287312    	-165.20179
164        	164Dy                        	163.9291748    	-165.39481
165        	165Ho                        	164.9303221    	-164.93233
166        	166Er                        	165.9303011    	-165.55812
167        	167Er                        	166.9320562    	-164.52949
168        	168Er                        	167.9323783    	-164.83570
169        	169Tm                        	168.9342133    	-163.73262
...        	...                          	...            	...
204        	204Pb                        	203.9730436    	-148.78044
205        	205Tl                        	204.9744275    	-148.09757
206        	206Pb                        	205.9744653    	-148.66859
207        	207Pb                        	206.9758969    	-147.94129
208        	208Pb                        	207.9766521    	-147.84406
209        	209Bi                        	208.9803986    	-144.96044
210        	210Po                        	209.9828737    	-143.26113
211        	211Po                        	210.9866532    	-140.34678
212        	212Po                        	211.9888680    	-138.88993
213        	213Po                        	212.992857     	-135.78043
214        	214Po                        	213.9952014    	-134.20287
215        	215At                        	214.998653     	-131.59395
216        	216Rn                        	216.000274     	-130.69023
217        	217Rn                        	217.003928     	-127.89278
218        	218Rn                        	218.0056013    	-126.94034
219        	219Fr                        	219.009252     	-124.14596
220        	220Ra                        	220.011028     	-123.09786
221        	221Ra                        	221.013917     	-121.01300
222        	222Ra                        	222.015375     	-120.26111
223        	223Ra                        	223.0185022    	-117.95437
224        	224Ra                        	224.0202118    	-116.96812
225        	225Ac                        	225.023230     	-114.76291
226        	226Th                        	226.024903     	-113.81075
227        	227Th                        	227.0277041    	-111.80777
228        	228Th                        	228.0287411    	-111.44804
229        	229Th                        	229.031762     	-109.24032
230        	230Th                        	230.0331338    	-108.56872
231        	231Pa                        	231.035884     	-106.61316
232        	232U                         	232.0371548    	-106.03564
233        	233U                         	233.0396343    	-104.33223
234        	234U                         	234.0409503    	-103.71262
235        	235U                         	235.0439281    	-101.54504
236        	236U                         	236.0455661    	-100.62548
237        	237Np                        	237.0481734    	-98.80303
...        	...                          	...            	...
If I got it correctly, the five N = 82 isotones around 140Ce have the lowest value of m(nuclide) - mass number×(m(4He)/4) among all nuclides, followed by 136Ba (-171.33421 MeV) and 134Ba (-170.18468 MeV). 103.166.228.86 (talk) 10:21, 18 April 2024 (UTC)
thread_title:  Mass excesses measured using mass of <sup>4</sup>He to show trend of alpha decay energies