Re: [fluka-discuss]: About the age of the particle in MGDRAW

From: Luigi Salvatore Esposito <>
Date: Fri, 8 Mar 2019 17:33:21 +0000

Dear Qi,
first of all, please keep the mail exchange on the list.

Your first question is not clear to me.

T0 is the time when the last (gamma, n) reaction occurred, i.e. the time when the neutrons are generated.

ATRACK stores the time at the end of each step, and therefore, (ATRACK - T0) is the time elapsed since the neutron was generated and transported to the end of the step.

Best regards, luigi

On 8 Mar 2019, at 17:25,<> wrote:

Dear luigi,

Thanks for your reply. The way you suggest is much more easy and convinient than that I used.
But I still have two questions. First, If I can conbine all the step for a neutron, I can use the total energy and the coordinate at the two point of the first step to calculate the time interval (dt) between them, and then to calculate the birth time of the neutron(Tb) by Tb=T1-dt, where T1 is the age of the first step which is given by ATRACK. Am I right? It worth mention that, in my simulation there is only one targe that can produce photo-neutron and no background material(except the vaccum and blackhole) exist. Second, in your code of the attached,
      IF ( JTRACK .EQ. 8 ) THEN
         WRITE (70,*) NCASE, ICODE, LTRACK, T0, SNGL (ATRACK) - T0,
where, SNGL (ATRACK) - T0 means the time at the end point of each step relative to the birth time of neutron?

Best Regards


发件人:"Luigi Salvatore Esposito" <<>>
发送时间:2019-03-08 19:40:47 (星期五)
收件人: "<>" <<>>
抄送: Fluka <<>>, "Francesco Cerutti" <<>>
主题: Re: [fluka-discuss]: About the age of the particle in MGDRAW

Dear Qi,

ATRACK gives the time at the end of each step and it is computed from the start of the event.

If you want the time when a photo-neutron as been produced, you need to use USDRAW, activated by WHAT(4) in USERDUMP,
filter on a photo-nuclear interaction (ICODE=101 and JTRACK=7) and check that at least a neutron is among the secondaries.

Attached you can find the mgdraw modified for the scope.

Hope this could help.

Cheers luigi

On 7 Mar 2019, at 16:40,<> wrote:

Dear Fluka experts,
I want to simulate the transport process of electrons being injected into a Ta target and record the data of photoneutrons. With MGDRAW user routine, I can get the age of the neutron by variable ATRACK. But when I modified the MGDRAW.f file as follow: SUBROUTINE MGDRAW ( ICODE, MREG )
      IF ( JTRACK .EQ. 8 ) THEN
     & SNGL (WTRACK)
         WRITE (92,*) ( SNGL (XTRACK (I)), SNGL (YTRACK (I)),
     & SNGL (ZTRACK (I)), I = 0, NTRACK ),
     & ( SNGL (DTRACK (I)), I = 1, MTRACK ),
     & SNGL (CTRACK)
I will get the data as follow(here I only show the data of one neutron for example):
           1 0 8 0.939982057 9.70298983E-03
  0.322248042 6.06961399E-02 5.58620729E-02 -5.55111512E-17 9.48838666E-02 -0.100359999 0.359747052
 -0.895762861 9.50326771E-02 -0.434255302 4.14305951E-10 4
           1 0 8 0.939982057 9.70298983E-03
  -5.55111512E-17 9.48838666E-02 -0.100359999 -79.0000000 8.47609901 -38.3986320 88.1929855
 -0.895762861 9.50326771E-02 -0.434255302 9.92574911E-08 4

These data means that there are two step of this neutron, so 3 point of the path exist. However, there are only two data of the age of the neutron. Why? If I want to get the birth time of neutron, which age is what I need? Is it the first one? If it is ture, what is the age of neutron at the end point of the last step?
Best Regards


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Received on Fri Mar 08 2019 - 20:06:55 CET

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