Template talk:Ra to Es by HL

Latest comment: 9 years ago by Limulus in topic Fission and capture cross-sections

I have an idea. If you take the log of the HL, you'll get values from just over 0 to just over 10. One could do a greyscale for that...

HL	   log HL  16 – log HL	*16 -1	DEC2HEX
				
1		0	16	255	FF
10		1	15	239	EF
100		2	14	223	DF
1000		3	13	207	CF
10000		4	12	191	BF
100000		5	11	175	AF
1000000		6	10	159	9F
10000000	7	9	143	8F
100000000	8	8	127	7F
1000000000	9	7	111	6F
10000000000	10	6	95	5F

For the scale. -- Limulus (talk) 22:57, 9 July 2013 (UTC)Reply

Isotope	HL (a)	     log HL  16-log HL  *16 -1  DEC2HEX
					
235Np	1.084		0.035	15.965	254	FE
252Es	1.291		0.111	15.889	253	FD
228Th	1.9116		0.281	15.719	250	FA
252Cf	2.645		0.422	15.578	248	F8
236Pu	2.858		0.456	15.544	248	F8
228Ra	5.75		0.760	15.240	243	F3
250Cf	13.08		1.117	14.883	237	ED
241Pu	14.29		1.155	14.845	237	ED
244Cm	18.1		1.258	14.742	235	EB
227Ac	21.772		1.338	14.662	234	EA
243Cm	29.1		1.464	14.536	232	E8
232U	68.9		1.838	14.162	226	E2
238Pu	87.7		1.943	14.057	224	E0
242mAm	141		2.149	13.851	221	DD
249Cf	351		2.545	13.455	214	D6
241Am	432.2		2.636	13.364	213	D5
251Cf	900		2.954	13.046	208	D0
247Bk	1380		3.140	12.860	205	CD
226Ra	1600		3.204	12.796	204	CC
246Cm	4760		3.678	12.322	196	C4
240Pu	6561		3.817	12.183	194	C2
229Th	7340		3.866	12.134	193	C1
243Am	7370		3.867	12.133	193	C1
250Cm	8300		3.919	12.081	192	C0
245Cm	8500		3.929	12.071	192	C0
239Pu	24110		4.382	11.618	185	B9
231Pa	32760		4.515	11.485	183	B7
230Th	75380		4.877	11.123	177	B1
236Np	154000		5.188	10.812	172	AC
233U	159200		5.202	10.798	172	AC
234U	245500		5.390	10.610	169	A9
248Cm	348000		5.542	10.458	166	A6
242Pu	375000		5.574	10.426	166	A6
237Np	2144000		6.331	9.669	154	9A
247Cm	15600000	7.193	8.807	140	8C
236U	23420000	7.370	8.630	137	89
244Pu	80000000	7.903	8.097	129	81
235U	704000000	8.848	7.152	113	71
238U	4468000000	9.650	6.350	101	65
232Th	14050000000	10.148	5.852	93	5D

-- Limulus (talk) 21:10, 9 July 2013 (UTC)Reply

An oversight! "248Bk [...] >9 a" so:
248Bk	9		0.954	15.046	240	F0

-- Limulus (talk) 10:16, 26 January 2014 (UTC)Reply

[1] (probably source of ">9 a") states that "the alpha half-life is probably greater than 300 y" ("and a lower limit for the β half-life can be set at about 104 y") so let's use 300.
248Bk	300		2.477	13.523	215	D7

-- Limulus (talk) 10:59, 26 January 2014 (UTC)Reply

Decay modes

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Decay modes, from File:NuclideMap stitched.png and Isotopes_of_americium#Americium-242m:

Isotope	HL (a)	Normal Decay Mode(s)
		
235Np	1.084	electron capture
252Es	1.291	alpha (78%), electron capture (22%)
228Th	1.9116	alpha
252Cf	2.645	alpha (96.91%), spontaneous fission (3.09%)
236Pu	2.858	alpha
228Ra	5.75	beta-
250Cf	13.08	alpha (99.92%), spontaneous fission (0.08%)
241Pu	14.29	beta-
244Cm	18.1	alpha
227Ac	21.772	beta- (98.62%), alpha (1.38%)
243Cm	29.1	alpha (99.71%), electron capture (0.29%)
232U	68.9	alpha
238Pu	87.7	alpha
242mAm	141	isomeric transiton (99.54%), alpha (0.46%)
248Bk	>300?	alpha
249Cf	351	alpha
241Am	432.2	alpha
251Cf	900	alpha
247Bk	1380	alpha
226Ra	1600	alpha
246Cm	4760	alpha (99.7%), spontaneous fission (0.3%)
240Pu	6561	alpha
229Th	7340	alpha
243Am	7370	alpha
250Cm	8300	spontaneous fission (74%), alpha (18%)
245Cm	8500	alpha
239Pu	24110	alpha
231Pa	32760	alpha
230Th	75380	alpha
236Np	154000	electron capture (86.3%), beta- (13.5%)
233U	159200	alpha
234U	245500	alpha
248Cm	348000	alpha (91.61%), spontaneous fission (8.39%)
242Pu	375000	alpha
237Np	2144000	alpha
247Cm	15600000	alpha
236U	23420000	alpha
244Pu	80000000	alpha
235U	704000000	alpha
238U	4468000000	alpha
232Th	14050000000	alpha

Observations:

  • Beta/EC in relatively short HL isotopes; < 22y EXCEPT Np-236...
  • 242mAm a special case. Setting the HL cut-off > 141y would get rid of that.
  • Long half lives pretty much all alpha exclusively; spontaneous fission increasingly happens in the heavier isotopes (246+).

-- Limulus (talk) 04:11, 18 February 2014 (UTC)Reply

Mass number

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Arranged by mass number; note isobars for several:

226Ra	1600						
227Ac	21.772						
228Ra	5.75		228Th	1.9116			
229Th	7340						
230Th	75380						
231Pa	32760						
232Th	14050000000	232U	68.9			
233U	159200						
234U	245500						
235U	704000000	235Np	1.084			
236U	23420000	236Np	154000		236Pu	2.858
237Np	2144000						
238U	4468000000	238Pu	87.7			
239Pu	24110						
240Pu	6561						
241Am	432.2		241Pu	14.29			
242Pu	375000		242mAm	141			
243Am	7370		243Cm	29.1			
244Pu	80000000	244Cm	18.1			
245Cm	8500						
246Cm	4760						
247Cm	15600000	247Bk	1380			
248Cm	348000		248Bk	>300?			
249Cf	351						
250Cm	8300		250Cf	13.08			
251Cf	900						
252Cf	2.645		252Es	1.291			

Observation:

  • (Except for a few notable cases like 241) it's the more neutron-rich isotope that is more stable.

-- Limulus (talk) 09:13, 18 February 2014 (UTC)Reply

Nuclear spin

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Nuclear spin info from the respective isotope pages. "Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses."

226Ra	0+
228Ra	0+
227Ac	3/2-
228Th	0+
229Th	5/2+
230Th	0+
232Th	0+
231Pa	3/2-
232U	0+
233U	5/2+
234U	0+
235U	7/2-
236U	0+
238U	0+
235Np	5/2+
236Np	(6-)
237Np	5/2+
236Pu	0+
238Pu	0+
239Pu	1/2+
240Pu	0+
241Pu	5/2+
242Pu	0+
244Pu	0+
241Am	5/2-
242mAm	5-
243Am	5/2-
243Cm	5/2+
244Cm	0+
245Cm	7/2+
246Cm	0+
247Cm	9/2-
248Cm	0+
250Cm	0+
247Bk	(3/2-)
248Bk	6+#
249Cf	9/2-
250Cf	0+
251Cf	1/2+
252Cf	0+
252Es	5-

Observation:

  • All even mass number isotopes have zero spin EXCEPT Np-236, Am-242m, 248Bk and 252Es, which are the only isotopes on the list that are even from an odd number of protons plus an odd number of neutrons.

-- Limulus (talk) 22:51, 18 February 2014 (UTC)Reply

By spin:

239Pu	1/2+
251Cf	1/2+

227Ac	3/2-
231Pa	3/2-
247Bk	(3/2-)

229Th	5/2+
233U	5/2+
235Np	5/2+
237Np	5/2+
241Pu	5/2+
241Am	5/2-
243Am	5/2-
243Cm	5/2+

235U	7/2-
245Cm	7/2+

247Cm	9/2-
249Cf	9/2-

242mAm	5-
252Es	5-

236Np	(6-)
248Bk	6+#

-- Limulus (talk) 22:40, 19 February 2014 (UTC)Reply

Observation:

  • I find this very curious:
241Pu   5/2+
241Am   5/2-
243Am   5/2-
243Cm   5/2+

Not only do the pairs have equal but opposite signs (note Pu-241 beta decays to Am-241; are the signs the result of n to p ratio? e.g. 2n3p -> 3p2n or something along those lines...) but also the two isotopes of Am (same number of protons, separated by a pair of neutrons) have the same value while Pu-241 and Cm-243 (with the same value) have the same number of neutrons (separated by a pair of protons).

-- Limulus (talk) 04:47, 20 February 2014 (UTC)Reply

edit

Neat! I've discovered some trends. First, the obvious one:

Iso.	A	Z	N	HL
226Ra	226	88	138	1600
232Th	232	90	142	14050000000
238U	238	92	146	4468000000
244Pu	244	94	150	80000000
250Cm	250	96	154	8300

Each of these is spaced by 2p+4n and surrounded by a 'dead zone' (if you exclude Ac-227 anyway). This is what originally got me interested in making this template. (Note: if you follow the line past radium, you'll end up at 208Pb; the LAST known stable isotope... coincidence? -- Limulus (talk) 03:00, 25 July 2014 (UTC))Reply

Now, I also found that if you take the even-even isotopes, they're more stable with more N (up to 152) for any given Z, to the above trend line:

226Ra	226	88	138	1600
228Ra	228	88	140	5.75
				
228Th	228	90	138	1.9116
230Th	230	90	140	75380
232Th	232	90	142	14050000000
				
232U	232	92	140	68.9
234U	234	92	142	245500
236U	236	92	144	23420000
238U	238	92	146	4468000000
				
236Pu	236	94	142	2.858
238Pu	238	94	144	87.7
240Pu	240	94	146	6561
242Pu	242	94	148	375000
244Pu	244	94	150	80000000
				
244Cm	244	96	148	18.1
246Cm	246	96	150	4760
248Cm	248	96	152	348000
250Cm	250	96	154	8300
				
250Cf	250	98	152	13.08
252Cf	252	98	154	2.645

Then I looked at the odd-odd isotopes:

252Es	252	99	153	1.291
242mAm	242	95	147	141
248Bk	248	97	151	300
236Np	236	93	143	154000

Drop 252 (short HL, upper right) and arrange by mass:

236Np	236	93	143	154000
242mAm	242	95	147	141
248Bk	248	97	151	300

Note the trend; again spaced 2p+4n. Coincidence?!?

Finally, I looked at the odd-p/even-n and even-p/odd-n isotopes:

235Np	235	93	142	1.084
227Ac	227	89	138	21.772
241Am	241	95	146	432.2
247Bk	247	97	150	1380
243Am	243	95	148	7370
231Pa	231	91	140	32760
237Np	237	93	144	2144000
				
241Pu	241	94	147	14.29
243Cm	243	96	147	29.1
249Cf	249	98	151	351
251Cf	251	98	153	900
229Th	229	90	139	7340
245Cm	245	96	149	8500
239Pu	239	94	145	24110
233U	233	92	141	159200
247Cm	247	96	151	15600000
235U	235	92	143	704000000

I was hoping to see a 2p+4n pattern. But no. Nor did I see any obvious ones for 4n+1 or 4n+3 decay chains. But then I noticed this:

227Ac	227	89	138	21.772
229Th	229	90	139	7340
231Pa	231	91	140	32760
233U	233	92	141	159200
235Np	235	93	142	1.084
				
235U	235	92	143	704000000
237Np	237	93	144	2144000
239Pu	239	94	145	24110
241Am	241	95	146	432.2
243Cm	243	96	147	29.1
				
241Pu	241	94	147	14.29
243Am	243	95	148	7370
245Cm	245	96	149	8500
247Bk	247	97	150	1380
249Cf	249	98	151	351
				
247Cm	247	96	151	15600000
				
251Cf	251	98	153	900

Noting the Bk-249 discontinuity in the upper right corner, the trend is pretty straightforward along +p+n paths (which continue into the dead zone, i.e. just to the right of each of the major islands, like Th-232) that increase to a maximal value somewhere along their length and then decline.

-- Limulus (talk) 01:08, 25 July 2014 (UTC)Reply

"Somewhere" being U (92p) or if not available, Cm (96p). -- Limulus (talk) 02:55, 25 July 2014 (UTC)Reply

Fission and capture cross-sections

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Brookhaven National Laboratory has interactive charts of nuclides:

and while they don't have fission info for all of the ones in this template, here's what they have; measured in barns:

	Fission 	Capture 

223Ra	7.002E-1	1.300E+2
226Ra	7.002E-6	1.279E+1

227Ac	2.901E-4	9.020E+2

227Th	2.020E+2	1.535E+3
228Th	3.001E-1	1.199E+2
229Th	3.164E+1	6.338E+1
233Th	1.500E+1	1.450E+3

231Pa	2.087E-2	2.006E+2
232Pa	9.780E+2	6.513E+2

232U	7.676E+1	7.519E+1
233U	5.313E+2	4.526E+1
234U	6.709E-2	1.009E+2
235U	5.850E+2	9.869E+1
236U	4.710E-2	5.133
237U	4.165E-1	4.754E+2
238U	1.679E-5	2.683
239U	1.411E+1	2.057E+1
240U	1.079E-3	1.916E+1
241U	4.165E-1	4.761E+2

235Np	2.000E+1	1.500E+2
236Np	3.011E+3	1.258E+2
237Np	2.036E-2	1.617E+2
238Np	2.070E+3	4.502E+2

236Pu	1.648E+2	3.123E+1
237Pu	2.102E+3	5.407E+2
238Pu	1.700E+1	5.608E+2
239Pu	7.479E+2	2.707E+2
240Pu	6.404E-2	2.875E+2
241Pu	1.012E+3	3.630E+2
242Pu	1.042E-3	1.916E+1
243Pu	1.814E+2	8.813E+1

241Am	3.139		6.188E+2
242Am	2.095E+3	2.190E+2
243Am	7.393E-2	7.511E+1
244Am	2.300E+3	6.001E+2

241Cm	2.600E+3	2.504E+2
242Cm	3.020		1.687E+1
243Cm	6.135E+2	1.305E+2
244Cm	1.037		1.510E+1
245Cm	2.141E+3	3.589E+2
246Cm	1.442E-1	1.311
247Cm	1.112E+2	5.692E+1
248Cm	8.736E-2	2.444
249Cm	1.025E+1	1.750
250Cm	2.089E-3	8.537E+1

249Bk	3.993		7.455E+2
250Bk	9.588E+2	3.532E+2

249Cf	1.633E+3	4.965E+2
251Cf	5.323E+3	2.862E+3
252Cf	3.217E+1	2.049E+1
253Cf	1.136E+3	3.413E+2
254Cf	2.000		4.501

254Es	1.966E+3	2.817E+1
255Es	1.343E+1	5.502E+1

255Fm	3.361E+3	2.601E+1

For those isotopes with HL >1y found in the template, AND where the ratio of fission to capture cross sections is listed by BNL, AND is 0.1 or greater:

229Th	*	0.499
232U		1.021
233U	*	11.739
235U	*	5.928
235Np		0.133
236Np	*	23.935
236Pu		5.277
239Pu	*	2.763
241Pu	*	2.788
243Cm	*	4.701
245Cm	*	5.965
246Cm		0.11
247Cm	*	1.954
249Cf	*	3.289
251Cf	*	1.86
252Cf		1.57

NOTE: an asterisk indicates that it satisfies the fissile rule.

-- Limulus (talk) 07:50, 20 December 2014 (UTC)Reply