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From: Joshua Albert <joalbert_at_imap.iu.edu>

Date: Tue, 9 Apr 2013 15:51:57 -0700

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Dear FLUKA-ites,

I'm glad I found this, I was having a similar issue with the 2.22 MeV =

gammas from neutron capture on hydrogen.

Does anyone know why the RESNUCLEI rate of 2H production is ~150x higher =

with NEW-DEFA than with PRECISIO? When I run with PRECISIO, I find that =

the 2.2 MeV gamma production (found from USDRAW as suggested) nearly =

matches the RESNUCLEI rates for 2H. What could cause such a large =

discrepancy?

I will certainly use PRECISIO from now on, but I'd like to know why.

I was also somewhat concerned about using MGDRAW for this, as =

documentation =

(http://www.fluka.org/web_archive/earchive/prova/att-0814/UserRoutines.pdf=

) strongly recommends against using MGDRAW whenever low energy neutrons =

are involved. Should I be concerned about this?

Cheers!

Josh

On Jan 24, 2013, at 2:17 AM, Anton Lechner <Anton.Lechner_at_cern.ch> =

wrote:

*> 2013 11:17:17 +0100 (CET)
*

*> X-Virus-Scanned: clamav-milter 0.97.6 at smtp1.mi.infn.it
*

*> X-Virus-Status: Clean
*

*> Sender: owner-fluka-discuss_at_smtp2.mi.infn.it
*

*>=20
*

*> Dear,
*

*>=20
*

*> First of all, do not use NEW-DEFA as DEFAULTS setting but PRECISIO.=20
*

*>=20
*

*> Note that photons (with energy ~0.002223 MeV) produced in =
*

1-H(n,gamma)2-H interactions may still interact within your target, and =

therefore your USRBDX scoring of photons leaving the target is not the =

most suitable way to exactly count such neutron interactions. If you are =

interested to count individual photons produced in 1-H(n,gamma)2-H, I =

would rather use the MGDRAW routine, in particular the USDRAW entry. If =

activated via the USERDUMP card (see manual), USDRAW is called after =

physical interactions; secondaries like photons will then be available =

in the GENSTK common. The ICODE value for your neutron interaction is =

300. One can then for example loop over stack entries to retrieve =

particle type, energy and weight, e.g.:

*> DO 10 INP =3D 1, NP
*

*> WRITE(50,*) 'Particle=3D',KPART(INP),' Energy=3D',TKI(INP),=20=
*

*> & ' Weight=3D',WEI(INP) =20
*

*> 10 CONTINUE
*

*> In other words, if a 1-H(n,gamma)2-H interaction occurs you will =
*

obtain a ~0.002223 MeV photon on the stack after such a neutron capture.

*> You may find more information about MGDRAW (and USDRAW in particular) =
*

in the "Programming User Routines" lecture of the last advanced FLUKA =

course (TRIUMF2012).

*>=20
*

*> Concerning the scoring of residual nuclei, your approach is the =
*

correct one, i.e. you will get the number of 2-H directly in the =

RESNUCLE output (obviously per primary). One important point is the =

following (thanks to Francesco for reminding me this): the residuals =

from low-energy neutron interactions, such as the considered =

1-H(n,gamma)2-H, are only created for scoring purposes if one issues the =

RESNUCLE card. This means, no information about the residuals is =

available in USDRAW.

*>=20
*

*> Just as a general comment, I would like to remind you that many of =
*

your neutrons will just undergo elastic interactions in the target and =

eventually leave the target without being captured (at these neutron =

energies the capture cross section of 1-H being about two orders of =

magnitude smaller than the cross section for elastic scattering). You =

can account for neutrons leaving your target in the BXDRAW entry of =

MGDRAW.

*>=20
*

*> Cheers, Anton
*

*>=20
*

*>=20
*

*>=20
*

*> ________________________________________
*

*> From: owner-fluka-discuss_at_mi.infn.it [owner-fluka-discuss_at_mi.infn.it] =
*

on behalf of ssghodke_at_barc.gov.in [ssghodke_at_barc.gov.in]

*> Sent: 14 December 2012 13:24
*

*> To: fluka-discuss_at_fluka.org
*

*> Subject: thermal neutron capture in Hydrogen
*

*>=20
*

*> Dear fluka experts
*

*> We are trying to find out the reaction rate of the thermal neutron =
*

capture

*> reaction 1H(n,gamma)2D. We have taken a cylinder (rad =3D 1.784cm, H =3D=
*

10cm)

*> filled with hydrogen at a density 1g/cm3. We have used the following
*

*> tallies (by taking all the integral values, surface=3D1, volume=3D1):
*

*> 1) The USRTRACK to find out the integral thermal neutron fluence =
*

(Phi) in

*> the volume of the cylinder. This output is used to calculate reaction =
*

rate

*> (N*sigma*Phi) by taking sigma =3D 0.33 barns. (of course we got =
*

N*sigma*Phi=3D

*> 0.08696)
*

*> 2) The RESNUCLEI to find out the production of 2D.
*

*> 3) The USRBDX to find the out the number of capture gammas =
*

(2.2MeV)

*> crossing the cylinder.
*

*> But none of these three values match with each other. We are attaching =
*

the

*> input and output files. Please suggest any correction in the input =
*

file.

*>=20
*

*>=20
*

--Apple-Mail=_3BC6C58D-F9CF-4ACA-A7D8-31C918823979

Content-Transfer-Encoding: quoted-printable

Content-Type: text/html;

charset=us-ascii

<html><head><meta http-equiv=3D"Content-Type" content=3D"text/html =

charset=3Dus-ascii"></head><body style=3D"word-wrap: break-word; =

-webkit-nbsp-mode: space; -webkit-line-break: after-white-space; =

"><div>Dear FLUKA-ites,</div><div><br></div>I'm glad I found this, I was =

having a similar issue with the 2.22 MeV gammas from neutron capture on =

hydrogen.<div><br></div><div>Does anyone know why the RESNUCLEI rate of =

2H production is ~150x higher with NEW-DEFA than with PRECISIO? =

When I run with PRECISIO, I find that the 2.2 MeV gamma production =

(found from USDRAW as suggested) nearly matches the RESNUCLEI rates for =

2H. What could cause such a large =

discrepancy?</div><div><br></div><div>I will certainly use PRECISIO from =

now on, but I'd like to know why.</div><div><br></div><div>I was also =

somewhat concerned about using MGDRAW for this, as documentation (<a =

href=3D"http://www.fluka.org/web_archive/earchive/prova/att-0814/UserRouti=

nes.pdf">http://www.fluka.org/web_archive/earchive/prova/att-0814/UserRout=

ines.pdf</a>) strongly recommends against using MGDRAW whenever low =

energy neutrons are involved. Should I be concerned about =

this?</div><div><br></div><div>Cheers!</div><div><br></div><div>Josh</div>=

<div><br><div><div>On Jan 24, 2013, at 2:17 AM, Anton Lechner <<a =

href=3D"mailto:Anton.Lechner_at_cern.ch">Anton.Lechner_at_cern.ch</a>> =

wrote:</div><br class=3D"Apple-interchange-newline"><blockquote =

type=3D"cite">2013 11:17:17 +0100 (CET)<br>X-Virus-Scanned: =

clamav-milter 0.97.6 at <a =

href=3D"http://smtp1.mi.infn.it">smtp1.mi.infn.it</a><br>X-Virus-Status: =

Clean<br>Sender: <a =

href=3D"mailto:owner-fluka-discuss_at_smtp2.mi.infn.it">owner-fluka-discuss_at_s=

mtp2.mi.infn.it</a><br><br>Dear,<br><br>First of all, do not use =

NEW-DEFA as DEFAULTS setting but PRECISIO. <br><br>Note that photons =

(with energy ~0.002223 MeV) produced in 1-H(n,gamma)2-H interactions may =

still interact within your target, and therefore your USRBDX scoring of =

photons leaving the target is not the most suitable way to exactly count =

such neutron interactions. If you are interested to count individual =

photons produced in 1-H(n,gamma)2-H, I would rather use the MGDRAW =

routine, in particular the USDRAW entry. If activated via the USERDUMP =

card (see manual), USDRAW is called after physical interactions; =

secondaries like photons will then be available in the GENSTK common. =

The ICODE value for your neutron interaction is 300. One can then for =

example loop over stack entries to retrieve particle type, energy and =

weight, e.g.:<br> DO 10 INP =3D 1, =

NP<br> =

WRITE(50,*) =

'Particle=3D',KPART(INP),' Energy=3D',TKI(INP), <br> =

& =

&n=

bsp; ' Weight=3D',WEI(INP) <br> 10 =

CONTINUE<br>In other words, if a 1-H(n,gamma)2-H interaction =

occurs you will obtain a ~0.002223 MeV photon on the stack after such a =

neutron capture.<br>You may find more information about MGDRAW (and =

USDRAW in particular) in the "Programming User Routines" lecture of the =

last advanced FLUKA course (TRIUMF2012).<br><br>Concerning the scoring =

of residual nuclei, your approach is the correct one, i.e. you will get =

the number of 2-H directly in the RESNUCLE output (obviously per =

primary). One important point is the following (thanks to Francesco for =

reminding me this): the residuals from low-energy neutron interactions, =

such as the considered 1-H(n,gamma)2-H, are only created for scoring =

purposes if one issues the RESNUCLE card. This means, no information =

about the residuals is available in USDRAW.<br><br>Just as a general =

comment, I would like to remind you that many of your neutrons will just =

undergo elastic interactions in the target and eventually leave the =

target without being captured (at these neutron energies the capture =

cross section of 1-H being about two orders of magnitude smaller than =

the cross section for elastic scattering). You can account for neutrons =

leaving your target in the BXDRAW entry of MGDRAW.<br><br>Cheers, =

Anton<br><br><br><br>________________________________________<br>From: =

<a =

href=3D"mailto:owner-fluka-discuss_at_mi.infn.it">owner-fluka-discuss_at_mi.infn=

.it</a> [<a =

href=3D"mailto:owner-fluka-discuss_at_mi.infn.it">owner-fluka-discuss_at_mi.infn=

.it</a>] on behalf of <a =

href=3D"mailto:ssghodke_at_barc.gov.in">ssghodke_at_barc.gov.in</a> [<a =

href=3D"mailto:ssghodke_at_barc.gov.in">ssghodke_at_barc.gov.in</a>]<br>Sent: =

14 December 2012 13:24<br>To: <a =

href=3D"mailto:fluka-discuss_at_fluka.org">fluka-discuss_at_fluka.org</a><br>Sub=

ject: thermal neutron capture in Hydrogen<br><br>Dear fluka =

experts<br>We are trying to find out the reaction rate of the thermal =

neutron capture<br>reaction 1H(n,gamma)2D. We have taken a cylinder (rad =

=3D 1.784cm, H =3D 10cm)<br>filled with hydrogen at a density 1g/cm3. We =

have used the following<br>tallies (by taking all the integral values, =

surface=3D1, volume=3D1):<br>1) The =

USRTRACK to find out the integral thermal neutron fluence (Phi) =

in<br>the volume of the cylinder. This output is used to calculate =

reaction rate<br>(N*sigma*Phi) by taking sigma =3D 0.33 barns. (of =

course we got N*sigma*Phi=3D<br>0.08696)<br>2) =

The RESNUCLEI to find out the production =

of 2D.<br>3) The USRBDX to find the out =

the number of capture gammas (2.2MeV)<br>crossing the cylinder.<br>But =

none of these three values match with each other. We are attaching =

the<br>input and output files. Please suggest any correction in the =

input file.<br><br><br></blockquote></div><br></div></body></html>=

--Apple-Mail=_3BC6C58D-F9CF-4ACA-A7D8-31C918823979--

Received on Wed Apr 10 2013 - 09:45:52 CEST

Date: Tue, 9 Apr 2013 15:51:57 -0700

--Apple-Mail=_3BC6C58D-F9CF-4ACA-A7D8-31C918823979

Content-Transfer-Encoding: quoted-printable

Content-Type: text/plain;

charset=us-ascii

Dear FLUKA-ites,

I'm glad I found this, I was having a similar issue with the 2.22 MeV =

gammas from neutron capture on hydrogen.

Does anyone know why the RESNUCLEI rate of 2H production is ~150x higher =

with NEW-DEFA than with PRECISIO? When I run with PRECISIO, I find that =

the 2.2 MeV gamma production (found from USDRAW as suggested) nearly =

matches the RESNUCLEI rates for 2H. What could cause such a large =

discrepancy?

I will certainly use PRECISIO from now on, but I'd like to know why.

I was also somewhat concerned about using MGDRAW for this, as =

documentation =

(http://www.fluka.org/web_archive/earchive/prova/att-0814/UserRoutines.pdf=

) strongly recommends against using MGDRAW whenever low energy neutrons =

are involved. Should I be concerned about this?

Cheers!

Josh

On Jan 24, 2013, at 2:17 AM, Anton Lechner <Anton.Lechner_at_cern.ch> =

wrote:

1-H(n,gamma)2-H interactions may still interact within your target, and =

therefore your USRBDX scoring of photons leaving the target is not the =

most suitable way to exactly count such neutron interactions. If you are =

interested to count individual photons produced in 1-H(n,gamma)2-H, I =

would rather use the MGDRAW routine, in particular the USDRAW entry. If =

activated via the USERDUMP card (see manual), USDRAW is called after =

physical interactions; secondaries like photons will then be available =

in the GENSTK common. The ICODE value for your neutron interaction is =

300. One can then for example loop over stack entries to retrieve =

particle type, energy and weight, e.g.:

obtain a ~0.002223 MeV photon on the stack after such a neutron capture.

in the "Programming User Routines" lecture of the last advanced FLUKA =

course (TRIUMF2012).

correct one, i.e. you will get the number of 2-H directly in the =

RESNUCLE output (obviously per primary). One important point is the =

following (thanks to Francesco for reminding me this): the residuals =

from low-energy neutron interactions, such as the considered =

1-H(n,gamma)2-H, are only created for scoring purposes if one issues the =

RESNUCLE card. This means, no information about the residuals is =

available in USDRAW.

your neutrons will just undergo elastic interactions in the target and =

eventually leave the target without being captured (at these neutron =

energies the capture cross section of 1-H being about two orders of =

magnitude smaller than the cross section for elastic scattering). You =

can account for neutrons leaving your target in the BXDRAW entry of =

MGDRAW.

on behalf of ssghodke_at_barc.gov.in [ssghodke_at_barc.gov.in]

capture

10cm)

(Phi) in

rate

N*sigma*Phi=3D

(2.2MeV)

the

file.

--Apple-Mail=_3BC6C58D-F9CF-4ACA-A7D8-31C918823979

Content-Transfer-Encoding: quoted-printable

Content-Type: text/html;

charset=us-ascii

<html><head><meta http-equiv=3D"Content-Type" content=3D"text/html =

charset=3Dus-ascii"></head><body style=3D"word-wrap: break-word; =

-webkit-nbsp-mode: space; -webkit-line-break: after-white-space; =

"><div>Dear FLUKA-ites,</div><div><br></div>I'm glad I found this, I was =

having a similar issue with the 2.22 MeV gammas from neutron capture on =

hydrogen.<div><br></div><div>Does anyone know why the RESNUCLEI rate of =

2H production is ~150x higher with NEW-DEFA than with PRECISIO? =

When I run with PRECISIO, I find that the 2.2 MeV gamma production =

(found from USDRAW as suggested) nearly matches the RESNUCLEI rates for =

2H. What could cause such a large =

discrepancy?</div><div><br></div><div>I will certainly use PRECISIO from =

now on, but I'd like to know why.</div><div><br></div><div>I was also =

somewhat concerned about using MGDRAW for this, as documentation (<a =

href=3D"http://www.fluka.org/web_archive/earchive/prova/att-0814/UserRouti=

nes.pdf">http://www.fluka.org/web_archive/earchive/prova/att-0814/UserRout=

ines.pdf</a>) strongly recommends against using MGDRAW whenever low =

energy neutrons are involved. Should I be concerned about =

this?</div><div><br></div><div>Cheers!</div><div><br></div><div>Josh</div>=

<div><br><div><div>On Jan 24, 2013, at 2:17 AM, Anton Lechner <<a =

href=3D"mailto:Anton.Lechner_at_cern.ch">Anton.Lechner_at_cern.ch</a>> =

wrote:</div><br class=3D"Apple-interchange-newline"><blockquote =

type=3D"cite">2013 11:17:17 +0100 (CET)<br>X-Virus-Scanned: =

clamav-milter 0.97.6 at <a =

href=3D"http://smtp1.mi.infn.it">smtp1.mi.infn.it</a><br>X-Virus-Status: =

Clean<br>Sender: <a =

href=3D"mailto:owner-fluka-discuss_at_smtp2.mi.infn.it">owner-fluka-discuss_at_s=

mtp2.mi.infn.it</a><br><br>Dear,<br><br>First of all, do not use =

NEW-DEFA as DEFAULTS setting but PRECISIO. <br><br>Note that photons =

(with energy ~0.002223 MeV) produced in 1-H(n,gamma)2-H interactions may =

still interact within your target, and therefore your USRBDX scoring of =

photons leaving the target is not the most suitable way to exactly count =

such neutron interactions. If you are interested to count individual =

photons produced in 1-H(n,gamma)2-H, I would rather use the MGDRAW =

routine, in particular the USDRAW entry. If activated via the USERDUMP =

card (see manual), USDRAW is called after physical interactions; =

secondaries like photons will then be available in the GENSTK common. =

The ICODE value for your neutron interaction is 300. One can then for =

example loop over stack entries to retrieve particle type, energy and =

weight, e.g.:<br> DO 10 INP =3D 1, =

NP<br> =

WRITE(50,*) =

'Particle=3D',KPART(INP),' Energy=3D',TKI(INP), <br> =

& =

&n=

bsp; ' Weight=3D',WEI(INP) <br> 10 =

CONTINUE<br>In other words, if a 1-H(n,gamma)2-H interaction =

occurs you will obtain a ~0.002223 MeV photon on the stack after such a =

neutron capture.<br>You may find more information about MGDRAW (and =

USDRAW in particular) in the "Programming User Routines" lecture of the =

last advanced FLUKA course (TRIUMF2012).<br><br>Concerning the scoring =

of residual nuclei, your approach is the correct one, i.e. you will get =

the number of 2-H directly in the RESNUCLE output (obviously per =

primary). One important point is the following (thanks to Francesco for =

reminding me this): the residuals from low-energy neutron interactions, =

such as the considered 1-H(n,gamma)2-H, are only created for scoring =

purposes if one issues the RESNUCLE card. This means, no information =

about the residuals is available in USDRAW.<br><br>Just as a general =

comment, I would like to remind you that many of your neutrons will just =

undergo elastic interactions in the target and eventually leave the =

target without being captured (at these neutron energies the capture =

cross section of 1-H being about two orders of magnitude smaller than =

the cross section for elastic scattering). You can account for neutrons =

leaving your target in the BXDRAW entry of MGDRAW.<br><br>Cheers, =

Anton<br><br><br><br>________________________________________<br>From: =

<a =

href=3D"mailto:owner-fluka-discuss_at_mi.infn.it">owner-fluka-discuss_at_mi.infn=

.it</a> [<a =

href=3D"mailto:owner-fluka-discuss_at_mi.infn.it">owner-fluka-discuss_at_mi.infn=

.it</a>] on behalf of <a =

href=3D"mailto:ssghodke_at_barc.gov.in">ssghodke_at_barc.gov.in</a> [<a =

href=3D"mailto:ssghodke_at_barc.gov.in">ssghodke_at_barc.gov.in</a>]<br>Sent: =

14 December 2012 13:24<br>To: <a =

href=3D"mailto:fluka-discuss_at_fluka.org">fluka-discuss_at_fluka.org</a><br>Sub=

ject: thermal neutron capture in Hydrogen<br><br>Dear fluka =

experts<br>We are trying to find out the reaction rate of the thermal =

neutron capture<br>reaction 1H(n,gamma)2D. We have taken a cylinder (rad =

=3D 1.784cm, H =3D 10cm)<br>filled with hydrogen at a density 1g/cm3. We =

have used the following<br>tallies (by taking all the integral values, =

surface=3D1, volume=3D1):<br>1) The =

USRTRACK to find out the integral thermal neutron fluence (Phi) =

in<br>the volume of the cylinder. This output is used to calculate =

reaction rate<br>(N*sigma*Phi) by taking sigma =3D 0.33 barns. (of =

course we got N*sigma*Phi=3D<br>0.08696)<br>2) =

The RESNUCLEI to find out the production =

of 2D.<br>3) The USRBDX to find the out =

the number of capture gammas (2.2MeV)<br>crossing the cylinder.<br>But =

none of these three values match with each other. We are attaching =

the<br>input and output files. Please suggest any correction in the =

input file.<br><br><br></blockquote></div><br></div></body></html>=

--Apple-Mail=_3BC6C58D-F9CF-4ACA-A7D8-31C918823979--

Received on Wed Apr 10 2013 - 09:45:52 CEST

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