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Update with scattering lengths measurements since 2000
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Paul Kienzle committed Oct 22, 2024
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3 changes: 3 additions & 0 deletions ChangeLog.rst
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Expand Up @@ -35,6 +35,9 @@ Modified:
* Update physical constants to CODATA 2022. Values have changed by as much
as 1e-7 (relative) in Avogadro number, Planck constant, J/eV, electron radius,
electron mass, neutron mass and atomic mass constant.
* Updated bound coherent scattering length for H-1, H-2, He-4, C-12,
O-16, O-17, O-18, Sn-119, Sm-154, Eu-153, Pb-207, Bi-209
* Updated total cross section for He, Kr, Xe

Breaking changes:

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4 changes: 2 additions & 2 deletions doc/sphinx/guide/contributing.rst
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Expand Up @@ -39,10 +39,10 @@ When all the tests run, create a pull request (PR) on the github page.
Windows user can use `TortoiseGit <http://code.google.com/p/tortoisegit/>`_
package which provides similar operations.

You can build the documentation as follows::
You can build the documentation as follows (linux, mac)::

pip install sphinx
(cd doc/sphinx && make clean html pdf)
(cd doc/sphinx && PYTHONPATH=../.. make clean html pdf)

You can see the result by pointing your browser to::

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114 changes: 71 additions & 43 deletions periodictable/nsf.py
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Expand Up @@ -85,20 +85,47 @@
been fixed. In particular, Zn-70 has b_c listed as 6.9 in the table,
but 6.0 in the source materials for the table.
Alternative tables from Sears\ [#Sears1992]\ [#Sears2006] and Dawidowski,
et al.\ [#Dawidowski2013] make different choices for the recommended values.
These are noted in periodictable issue #59
Note that enteries in the table have been measured independently, so the values
for the scattering length of an element or isotope may be inconsistent with
the values measured for the corresponding cross section. The comparison table
functions highlight these differences.
Tables from Sears\ [#Sears1992]\ [#Sears2006], Rauch\ [#Rauch2003] and
Dawidowski\ [#Dawidowski2013] make different choices for the recommended
values. These are noted in periodictable issue #59
`<https://github.com/pkienzle/periodictable/issues/59>`_
with changes from Sears to Rauch
`(a) <https://github.com/pkienzle/periodictable/issues/59#issuecomment-1693686953>`__
and from Rauch to Dawidowski
`(b) <https://github.com/pkienzle/periodictable/issues/59#issuecomment-1690212205>`__.
.. Note:
Enteries in the table have been measured independently, so the values
measured for the scattering length of an element or isotope may be
inconsistent with the values measured for the corresponding cross section.
The following newer measurements from the literature are included:
1H b_c -3.7423(12) => -3.7395(11) [1]
2H b_c 6.674(6) => 6.6681(27) [1]
4He b_c 3.26(3) => 3.0982(21) [3] (see also [5], which gives 3.075(6))
4He coherent = total cross sections computed from 4 pi b_c^2/100
nat-He computed from isotopic weighting of 3He and 4He
12C b_c 6.6535(14) => 6.6472(9) [1]
16O b_c 5.805(5) => 5.8037(29) [1]
17O b_c 5.6(5) => 5.867(4) [2]
18O b_c 5.84(7) => 6.009(5) [2]
119Sn b_c 6.28(3) => 6.2239(13) [1]
154Sm b_c 8.0(1.0) => 8.97(6) [4]
153Eu b_c 8.22(12) => 8.85(3) [4]
207Pb b_c 9.286(16) => 9.4024(13) [1]
209Bi b_c 8.532(2) => 8.5242(18) [1]
He total 1.34(2) => 1.188(5) [5] (ignored; using 4 pi b_c^2/100)
Ar total 0.683(4) => 0.683(5) [5] (ignored; existing value is more precise)
Kr total 7.68(13) => 7.685(26) [5]
Xe total --- => 4.344(17) [5]
[1] Snow (2020) 10.1103/PhysRevD.101.062004
[2] Fischer (2012) 10.1088/0953-8984/24/50/505105
[3] Haun (2020) 10.1103/PhysRevLett.124.012501
[4] Kohlmann (2016) 10.1515/zkri-2016-1984
[5] Haddock (2019) 10.1103/PhysRevC.100.064002
.. [#Rauch2003] Rauch, H. and Waschkowski, W. (2003)
Neutron Scattering Lengths in ILL
Expand Down Expand Up @@ -447,6 +474,8 @@ def scattering_by_wavelength(self, wavelength):
if self.nsf_table is None:
ones = 1 if np.isscalar(wavelength) else np.ones_like(wavelength)
return ones*self.b_c_complex, ones*self.total
#energy = neutron_energy(wavelength)
#b_c = np.interp(energy, self.nsf_table[0], self.nsf_table[1])
b_c = np.interp(wavelength, self.nsf_table[0], self.nsf_table[1])
# TODO: sigma_s should include an incoherent contribution
sigma_s = _4PI_100*abs(b_c)**2 # 1 barn = 1 fm^2 1e-2 barn/fm^2
Expand Down Expand Up @@ -517,6 +546,7 @@ def energy_dependent_init(table):
el = getattr(table, el_name)
atom = el if iso_num is None else el[iso_num]
xs = asarray(re_a) + 1j*asarray(im_a)
#atom.neutron.nsf_table = asarray(energy)*1000, xs
atom.neutron.nsf_table = wavelength[::-1], xs[::-1]
#print(f"adding {atom}")

Expand Down Expand Up @@ -593,17 +623,6 @@ def init(table, reload=False):
if element.neutron is missing:
element.neutron = nsf

# Gaps in the table for Xe and Eu[151]. Fill them in with guesses from
# other columns even though they have not been measured directly. The
# assertions are here so that we remember to remove this code if the
# table eventually gets updated.
assert table.Xe.neutron.total is None
assert table.Eu[151].neutron.b_c is None
table.Xe.neutron.total = (
table.Xe.neutron.coherent + table.Xe.neutron.incoherent)
table.Eu[151].neutron.b_c = (
sqrt(table.Eu[151].neutron.coherent/_4PI_100))

for line in nsftableI.split('\n'):
columns = line.split(',')

Expand Down Expand Up @@ -898,7 +917,7 @@ def neutron_scattering(compound, density=None,
num_atoms += quantity
# PAK 2021-04-05: allow energy dependent b_c, b''
b_ck, sigma_sk = element.neutron.scattering_by_wavelength(wavelength)
#print(f"{element=}; {re_a=}; {im_a=}; {total_xs=}")
#print(f"{element=}; {b_ck=}; {sigma_sk=}")
b_c += quantity * b_ck
sigma_s += quantity * sigma_sk
is_energy_dependent |= element.neutron.is_energy_dependent
Expand Down Expand Up @@ -1269,17 +1288,24 @@ def sld_plot(table=None):
# Numbers followed by '*' are estimated.
# Numbers may be given as limit, e.g., <1.0e-6
#
# Formatting corrections by Paul Kienzle
# [Paul Kienzle]
# * Fix typos such as 70Zn b_c 6.9(1.0) => 6.0(1.0).
# * Update bound coherent scattering length for H-1, H-2, He-4, C-12,
# O-16, O-17, O-18, Sn-119, Sm-154, Eu-153, Pb-207, Bi-209
# * Update total cross section for He, Kr, Xe
# * Usd 63-Eu-151 b_c from 84Mug1. This change is moot since this isotope
# has energy dependent isotope coeffs.
# * Use calculated values for 4He coh and total, and natHe b_c, coh and total.

nsftable = """\
0-n-1,618 S,1/2,-37.0(6),0,-37.0(6),,43.01(2),,43.01(2),0
1-H,,,-3.7409(11),,,,1.7568(10),80.26(6),82.02(6),0.3326(7)
1-H-1,99.985,1/2,-3.7423(12),10.817(5),-47.420(14),+/-,1.7583(10),80.27(6),82.03(6),0.3326(7)
1-H-2,0.0149,1,6.674(6),9.53(3),0.975(60),,5.592(7),2.05(3),7.64(3),0.000519(7)
1-H-1,99.985,1/2,-3.7395(11),10.817(5),-47.420(14),+/-,1.7583(10),80.27(6),82.03(6),0.3326(7)
1-H-2,0.0149,1,6.6681(27),9.53(3),0.975(60),,5.592(7),2.05(3),7.64(3),0.000519(7)
1-H-3,12.26 Y,1/2,4.792(27),4.18(15),6.56(37),,2.89(3),0.14(4),3.03(5),<6.0E-6
2-He,,,3.26(3),,,,1.34(2),0,1.34(2),0.00747(1)
2-He,,,3.0985(21),,,,1.2065(16),0,1.2065(16),0.00747(1)
2-He-3,0.013,1/2,5.74(7),4.7(5),8.8(1.4),E,4.42(10),1.6(4),6.0(4),5333.0(7.0)
2-He-4,99.987,0,3.26(3),,,,1.34(2),0,1.34(2),0
2-He-4,99.987,0,3.0982(21),,,,1.2062(16),0,1.2062(16),0
3-Li,,,-1.90(3),,,,0.454(10),0.92(3),1.37(3),70.5(3)
3-Li-6,7.5,1,2.0(1),0.67(14),4.67(17),+/-,0.51(5),0.46(5),0.97(7),940.0(4.0)
3-Li-7,92.5,3/2,-2.22(2),-4.15(6),1.00(8),+/-,0.619(11),0.78(3),1.40(3),0.0454(3)
Expand All @@ -1288,15 +1314,15 @@ def sld_plot(table=None):
5-B-10,19.4,3,-0.2(4),-4.2(4),5.2(4),,0.144(6),3.0(4),3.1(4),3835.0(9.0)
5-B-11,80.2,3/2,6.65(4),5.6(3),8.3(3),,5.56(7),0.21(7),5.77(10),0.0055(33)
6-C,,,6.6484(13),,,,5.551(2),0.001(4),5.551(3),0.00350(7)
6-C-12,98.89,0,6.6535(14),,,,5.559(3),0,5.559(3),0.00353(7)
6-C-12,98.89,0,6.6472(9),,,,5.559(3),0,5.559(3),0.00353(7)
6-C-13,1.11,1/2,6.19(9),5.6(5),6.2(5),+/-,4.81(14),0.034(11),4.84(14),0.00137(4)
7-N,,,9.36(2),,,,11.01(5),0.50(12),11.51(11),1.90(3)
7-N-14,99.635,1,9.37(2),10.7(2),6.2(3),,11.03(5),0.50(12),11.53(11),1.91(3)
7-N-15,0.365,1/2,6.44(3),6.77(10),6.21(10),,5.21(5),0.00005(10),5.21(5),0.000024(8)
8-O,,,5.805(4),,,,4.232(6),0.000(8),4.232(6),0.00019(2)
8-O-16,99.75,0,5.805(5),,,,4.232(6),0,4.232(6),0.00010(2)
8-O-17,0.039,5/2,5.6(5),5.52(20),5.17(20),,4.20(22),0.004(3),4.20(22),0.236(10)
8-O-18,0.208,0,5.84(7),,,,4.29(10),0,4.29(10),0.00016(1)
8-O-16,99.75,0,5.8037(29),,,,4.232(6),0,4.232(6),0.00010(2)
8-O-17,0.039,5/2,5.867(4),5.52(20),5.17(20),,4.20(22),0.004(3),4.20(22),0.236(10)
8-O-18,0.208,0,6.009(5),,,,4.29(10),0,4.29(10),0.00016(1)
9-F-19,100,1/2,5.654(12),5.632(10),5.767(10),+/-,4.017(14),0.0008(2),4.018(14),0.0096(5)
10-Ne,,,4.566(6),,,,2.620(7),0.008(9),2.628(6),0.039(4)
10-Ne-20,90.5,0,4.631(6),,,,2.695(7),0,2.695(7),0.036(4)
Expand Down Expand Up @@ -1393,7 +1419,7 @@ def sld_plot(table=None):
35-Br,,,6.79(2),,,,5.80(3),0.10(9),5.90(9),6.9(2)
35-Br-79,50.49,3/2,6.79(7),,,+/-,5.81(2),0.15(6),5.96(13),11.0(7)
35-Br-81,49.31,3/2,6.78(7),,,+/-,5.79(12),0.05(2),5.84(12),2.7(2)
36-Kr,,,7.81(2),,,,7.67(4),0.01(14),7.68(13),25.0(1.0)
36-Kr,,,7.81(2),,,,7.67(4),0.01(14),7.685(26),25.0(1.0)
36-Kr-78,0.35,0,,,,,,0,,6.4(9)
36-Kr-80,2.5,0,,,,,,0,,11.8(5)
36-Kr-82,11.6,0,,,,,,0,,29.0(20.0)
Expand Down Expand Up @@ -1463,7 +1489,7 @@ def sld_plot(table=None):
50-Sn-116,14.3,0,6.10(1),,,,4.42(7),0,4.42(7),0.14(3)
50-Sn-117,7.61,1/2,6.59(8),0.22(10),-0.23(10),,5.28(8),0.3(3)*,5.6(3),2.3(5)
50-Sn-118,24.03,0,6.23(4),,,,4.63(8),0,4.63(8),0.22(5)
50-Sn-119,8.58,1/2,6.28(3),0.14(10),0.0(1),,4.71(8),0.3(3)*,5.0(3),2.2(5)
50-Sn-119,8.58,1/2,6.2239(13),0.14(10),0.0(1),,4.71(8),0.3(3)*,5.0(3),2.2(5)
50-Sn-120,32.86,0,6.67(4),,,,5.29(8),0,5.29(8),0.14(3)
50-Sn-122,4.72,0,5.93(3),,,,4.14(7),0,4.14(7),0.18(2)
50-Sn-124,5.94,0,6.15(3),,,,4.48(8),0,4.48(8),0.133(5)
Expand All @@ -1480,7 +1506,7 @@ def sld_plot(table=None):
52-Te-128,31.79,0,5.88(8),,,,4.36(10),0,4.36(10),0.215(8)
52-Te-130,34.48,0,6.01(7),,,,4.55(11),0,4.55(11),0.29(6)
53-I-127,100,5/2,5.28(2),6.6(2),3.4(2),,3.50(3),0.31(6),3.81(7),6.15(6)
54-Xe,,,4.69(4),,,,3.04(4),0,,23.9(1.2)
54-Xe,,,4.69(4),,,,3.04(4),0,4.344(17),23.9(1.2)
54-Xe-124,0.1,0,,,,,,0,,165.0(20.0)
54-Xe-126,0.09,0,,,,,,0,,3.5(8)
54-Xe-128,1.9,0,,,,,,0,,<8.0
Expand Down Expand Up @@ -1524,10 +1550,10 @@ def sld_plot(table=None):
62-Sm-149,13.8,7/2,18.7(28),,,E,63.5(6),137.0(5.0),200.0(5.0),42080.0(400.0)
62-Sm-150,7.4,0,14.0(3.0),,,,25.0(11.0),0,25.0(11.0),104.0(4.0)
62-Sm-152,26.7,0,-5.0(6),,,,3.1(8),0,3.1(8),206.0(6.0)
62-Sm-154,22.8,0,8.0(1.0),,,,11.0(2.0),0,11.0(2.0),8.4(5)
62-Sm-154,22.8,0,8.97(6),,,,11.0(2.0),0,11.0(2.0),8.4(5)
63-Eu,,,5.3(3),,,E,6.57(4),2.5(4),9.2(4),4530.0(40.0)
63-Eu-151,47.8,5/2,,,,E,5.5(2),3.1(4),8.6(4),9100.0(100.0)
63-Eu-153,52.8,5/2,8.22(12),,,,8.5(2),1.3(7),9.8(7),312.0(7.0)
63-Eu-151,47.8,5/2,6.92(15),,,E,5.5(2),3.1(4),8.6(4),9100.0(100.0)
63-Eu-153,52.8,5/2,8.85(3),,,,8.5(2),1.3(7),9.8(7),312.0(7.0)
64-Gd,,,9.5(2),,,E,29.3(8),151.0(2.0),180.0(2.0),49700.0(125.0)
64-Gd-152,0.2,0,10.0(3.0)*,,,,13.0(8.0),0,13.0(8.0),735.0(20.0)
64-Gd-154,2.2,0,10.0(3.0)*,,,,13.0(8.0),0,13.0(8.0),85.0(12.0)
Expand Down Expand Up @@ -1617,9 +1643,9 @@ def sld_plot(table=None):
82-Pb,,,9.401(2),,,,11.115(7),0.0030(7),11.118(7),0.171(2)
82-Pb-204,1.4,0,10.893(78),,,,12.3(2),0,12.3(2),0.65(7)
82-Pb-206,24.1,0,9.221(78),,,,10.68(12),0,10.68(12),0.0300(8)
82-Pb-207,22.1,1/2,9.286(16),,,+/-,10.82(9),0.002(2),10.82(9),0.699(10)
82-Pb-207,22.1,1/2,9.4024(13),,,+/-,10.82(9),0.002(2),10.82(9),0.699(10)
82-Pb-208,52.4,0,9.494(30),,,,11.34(5),0,11.34(5),0.00048(3)
83-Bi-209,100,9/2,8.532(2),8.26(1),8.74(1),,9.148(4),0.0084(19),9.156(4),0.0338(7)
83-Bi-209,100,9/2,8.5242(18),8.26(1),8.74(1),,9.148(4),0.0084(19),9.156(4),0.0338(7)
88-Ra-226,1620 Y,0,10.0(1.0),,,,13.0(3.0),0,13.0(3.0),12.8(1.5)
90-Th-232,100,0,10.31(3),,,,13.36(8),0,13.36(8),7.37(6)
91-Pa-231,32500 Y,3/2,9.1(3),,,,10.4(7),0.1(3.3),10.5(3.2),200.6(2.3)
Expand Down Expand Up @@ -1692,12 +1718,12 @@ def sld_table(wavelength=1, table=None, isotopes=True):
Neutron scattering length density table
atom mass density sld imag incoh
H 1.008 0.071 -1.582 0.000 10.690
1-H 1.008 0.071 -1.583 0.000 10.690
D 2.014 0.141 2.823 0.000 1.705
1-H 1.008 0.071 -1.582 0.000 10.691
D 2.014 0.141 2.820 0.000 1.709
T 3.016 0.212 2.027 0.000 0.453
He 4.003 0.122 0.598 0.000 0.035
He 4.003 0.122 0.569 0.000 0.003
3-He 3.016 0.092 1.054 0.272 0.652 *
4-He 4.003 0.122 0.598 0.000 0.035
4-He 4.003 0.122 0.569 0.000 0.000
...
248-Cm 248.072 13.569 2.536 0.000 0.207
* Energy dependent cross sections
Expand Down Expand Up @@ -1900,6 +1926,7 @@ def total_comparison_table(table=None, tol=None):
>>> total_comparison_table (tol=0.1)
Comparison of total cross section to (coherent + incoherent)
84-Kr 6.60 ----
Xe 4.34 3.04 42.9%
149-Sm 200.00 200.50 -0.2%
Eu 9.20 9.07 1.4%
Gd 180.00 180.30 -0.2%
Expand Down Expand Up @@ -1988,5 +2015,6 @@ def main():

if __name__ == "__main__":
main()
#coherent_comparison_table(tol=0.5)
#incoherent_comparison_table(tol=0.5)
#sld_table()
#coherent_comparison_table(tol=0.1)
#incoherent_comparison_table(tol=0.1)
7 changes: 2 additions & 5 deletions test/test_nsf.py
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Original file line number Diff line number Diff line change
Expand Up @@ -41,17 +41,14 @@ def test():
## Printing suppressed for the release version
#print("%2s %.3f % 7.3f % 7.3f"%(el.symbol,err,b_c,el.neutron.b_c))

# Check neutron_sld and neutron_xs against NIST calculator
# Note that we are using different tables, so a general comparison with
# NIST numbers is not possible, but ^30Si and ^18O are the same in both.
# Isotopic formula.
M = formula('Si[30]O[18]2',density=2.2)
sld,xs,depth = neutron_scattering(M,wavelength=4.75)
sld2 = neutron_sld(M,wavelength=4.75)
assert all(abs(v-w)<1e-10 for v,w in zip(sld,sld2))
#_summarize(M)
#_summarize(formula('O2',density=1.14))
# Alan's numbers:
assert abs(sld[0] - 3.27) < 0.01
assert abs(sld[0] - 3.33) < 0.01
assert abs(sld[1] - 0) < 0.01
#assert abs(xs[2] - 0.00292) < 0.00001 # TODO fix test
assert abs(xs[1] - 0.00569) < 0.00001
Expand Down

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