Physics of Hadron Showers in GEANT4 (progress report)
-
Upload
tatyana-diaz -
Category
Documents
-
view
14 -
download
0
description
Transcript of Physics of Hadron Showers in GEANT4 (progress report)
![Page 1: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/1.jpg)
PHYSICS OF HADRON SHOWERS IN GEANT4(PROGRESS REPORT)
Adam Para, Fermilab, March 23, 2010
1
![Page 2: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/2.jpg)
Methodology Use Hadr01 example In G4SteppingVerbose::StepInfo() select all the steps
with inelastic processes or captures. Write out all the step information and a list of created secondaries.
This is a PostStep method and the interacting particle no longer exists. The energy of the interacting particle is not easily accessible. A kludge: use the energy of the particle from the previous step, stored in a local variable.
Caveat 1: for some interactions the energy may not be available (if there was not previous, ‘elastic’ step)
Caveat 2: the energy is, in general overestimated by some variable amount, depending on the step length.
Will show 50 GeV protons in BGO, QGSP_BERT for now. Have implemented LCPhys, need to analyze the data
2
![Page 3: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/3.jpg)
Long List of Physics Processes Simulated
3
• inelastic collisions of protons (~10/50 GeV shower)
• inelastic collisions of neutrons ~1000
• neutron capture ~800
• inelastic interactions of mesons ~20
• Inelasti interaction of baryons ~0.1
• muon capture ~0.1
![Page 4: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/4.jpg)
Inelastic Nucleon Interactions
There are several categories of nucleons: Produced in high energy hadron-nucleus
QCD interaction Spallation nucleons Evaporation nucleons Nucleons produced in fission reactions
I have arbitrarily divided nucleon interactions into two groups: High energy ( E>1 GeV) Low energy (E<100 MeV)
4
![Page 5: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/5.jpg)
High Energy Neutron Interactions
5
![Page 6: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/6.jpg)
General Characteristics
6
• most of the interactions occur at very low energies
• prompt < 10 nsec• confined to a narrow
tube with ~5cm radius
![Page 7: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/7.jpg)
Multiplicity of Produced Particles
7
• Broad distribution, very long tail due to neutrons
• most of the time a single nucleus
• some elastic collisions, some events of nuclear breakup
![Page 8: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/8.jpg)
Spectra of Produced Particles
8
• leading particle effect• most of hadrons at low
energies• most of protons and
neutrons at very low (~nuclear energies)
![Page 9: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/9.jpg)
‘Nuclear Nucleons’
9
• very low energy neutrons, peaked at zero
• slightly higher energies when the nucleus breaks up
• protons definitely higher energy than neutrons
• <Ep> ~6-7 MeV
![Page 10: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/10.jpg)
Nuclear Reactions
10
• Kick out some number of nucleons from a nucleus
• Sometimes break Bi nucleus into two large pieces.
• The latter produces very large number of neutrons
![Page 11: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/11.jpg)
Energy Lost in a Collision
11
• very different modeling of hadron-nucleus interaction below and above 10 GeV
![Page 12: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/12.jpg)
Energy Lost vs Number of Neutrons
12
• Above 10 GeV: very large missing energy, not consistent with a small number of neutrons
• Below 10 GeV:• no nuclear fragments:
• missing energy increasing with number of neutrons
• bands (presumably) reflecting the number of mesons produced
• one nuclear fragment:• large number of neutrons• missing energy increasing
with number of neutrons• bands (presumably)
reflecting the number of mesons produced
• two nuclear fragments: • as above, but somewhat
less energy missing
•
![Page 13: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/13.jpg)
Neutrons, Low Energies (<100 MeV)
13
![Page 14: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/14.jpg)
General Characteristics
14
• most of the interactions occur at very low energies
• prompt < 10 nsec• rather broad tube
extending to ~20-30 cm radius
![Page 15: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/15.jpg)
Multiplicity of Produced Particles
15
• Mostly gammas• Narrow distribution, • most of the time a
single nucleus•
![Page 16: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/16.jpg)
Spectra of Produced Particles
16
• Mostly gammas• very soft nuclones
(evaporation)• one pion produced! (tail
of the Fermi motion?)
![Page 17: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/17.jpg)
‘Nuclear Nucleons’
17
• very low energy neutrons, peaked at zero
• slightly higher energies when the nucleus breaks up
• protons definitely higher energy than neutrons
• <Ep> ~6-7 MeV
![Page 18: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/18.jpg)
Nuclear Reactions
18
• Kick out small number of nucleons from a nucleus
• Sometimes break Bi nucleus into two large pieces.
• The latter produces larger number of neutrons
![Page 19: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/19.jpg)
Energy Lost in a Collision
19
• energy gain in fission events
• discrete lines of energy lost to evaporate nucleons
![Page 20: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/20.jpg)
Energy Lost vs Number of Neutrons
20
• small numbers of produced neutrons, small energy lost
![Page 21: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/21.jpg)
High Energy Proton Interactions (E>1 GeV)
21
![Page 22: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/22.jpg)
General Characteristics
22
• mix of high (50 GeV) and low (~1 GeV) interactions
• prompt < 10 nsec• confined to a narrow
tube with ~1 cm radius
![Page 23: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/23.jpg)
Multiplicity of Produced Particles
23
• Broad distribution, very long tail due to neutrons
• most of the time a single nucleus
• some elastic collisions, some events of nuclear breakup
![Page 24: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/24.jpg)
Spectra of Produced Particles
24
• leading particle effect• most of hadrons at low
energies• most of protons,
neutrons and gammas at very low (~nuclear energies)
![Page 25: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/25.jpg)
‘Nuclear Nucleons’
25
• very low energy neutrons, peaked at zero
• slightly higher energies when the nucleus breaks up
• protons definitely higher energy than neutrons
• <Ep> ~6-7 MeV
![Page 26: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/26.jpg)
Nuclear Reactions
26
• Kick out some number of nucleons from a nucleus
• Sometimes break Bi nucleus into two large pieces.
• The latter produces very large number of neutrons
![Page 27: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/27.jpg)
Energy Lost in a Collision
27
• very different modeling of hadron-nucleus interaction below and above 10 GeV
![Page 28: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/28.jpg)
Energy Lost vs Number of Neutrons
28
• Above 10 GeV: very large missing energy, not consistent with a small number of neutrons
• Below 10 GeV:• no nuclear fragments:
• missing energy increasing with number of neutrons
• bands (presumably) reflecting the number of mesons produced
• one nuclear fragment:• large number of neutrons• missing energy increasing
with number of neutrons• bands (presumably)
reflecting the number of mesons produced
• two nuclear fragments: • as above, but somewhat
less energy missing
•
![Page 29: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/29.jpg)
Proton Interactions, Low Energies (<100 MeV)
29
![Page 30: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/30.jpg)
General Characteristics
30
• most of the interactions occur at very low energies
• Coulomb barrier• promt < 10 nsec• confined to a narrow
tube with ~10 cm cm radius
![Page 31: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/31.jpg)
Multiplicity of Produced Particles
31
• neutrons and gamms produced only
• most of the time a single nucleus
•
![Page 32: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/32.jpg)
Spectra of Produced Particles
32
• soft protons• very soft neutrons• nuclear gammas
![Page 33: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/33.jpg)
‘Nuclear Nucleons’
33
• very low energy neutrons, peaked at zero
• slightly higher energies when the nucleus breaks up
• protons definitely higher energy than neutrons
• <Ep> ~6-7 MeV
![Page 34: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/34.jpg)
Nuclear Reactions
34
• Kick out a small number of nucleons from a nucleus
• Very seldom break Bi nucleus into two large pieces.
• The latter produces very large number of neutrons
![Page 35: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/35.jpg)
Energy Lost vs Number of Neutrons
35
• •
![Page 36: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/36.jpg)
Meson Interactions
36
![Page 37: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/37.jpg)
General Characteristics
37
• most of the interactions occur at very low energies
• promt < 10 nsec• confined to a narrow
tube with ~10 cm cm radius
![Page 38: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/38.jpg)
Multiplicity of Produced Particles
38
• Broad distribution, very long tail due to neutrons
• most of the time a single nucleus
• some elastic collisions, some events of nuclear breakup
![Page 39: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/39.jpg)
Spectra of Produced Particles
39
• leading particle effect• most of hadrons at low
energies• most of protons and
neutrons at very low (~nuclear energies)
![Page 40: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/40.jpg)
‘Nuclear Nucleons’
40
• very low energy neutrons, peaked at zero
• slightly higher energies when the nucleus breaks up
• protons definitely higher energy than neutrons
• <Ep> ~6-7 MeV
![Page 41: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/41.jpg)
Nuclear Reactions
41
• Kick out some number of nucleons from a nucleus
• Sometimes break Bi nucleus into two large pieces.
• The latter produces very large number of neutrons
![Page 42: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/42.jpg)
Energy Lost in a Collision
42
• very different modeling of hadron-nucleus interaction below and above 10 GeV
![Page 43: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/43.jpg)
Energy Lost vs Number of Neutrons
43
• Above 10 GeV: very large missing energy, not consistent with a small number of neutrons
• Below 10 GeV:• no nuclear fragments:
• missing energy increasing with number of neutrons
• bands (presumably) reflecting the number of mesons produced
• one nuclear fragment:• large number of neutrons• missing energy increasing with
number of neutrons• bands (presumably) reflecting
the number of mesons produced
• two nuclear fragments: • as above, but somewhat less
energy missing
•
![Page 44: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/44.jpg)
Baryon Interactions
44
![Page 45: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/45.jpg)
General Characteristics
45
• most of the interactions occur at very low energies
• prompt < 10 nsec• confined to a narrow
tube with few cm radius
![Page 46: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/46.jpg)
Multiplicity of Produced Particles
46
• Broad distribution, very long tail due to neutrons
•
![Page 47: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/47.jpg)
Spectra of Produced Particles
47
• very few and very soft particles produced (as a result of very low energy of the interacting baryons)
![Page 48: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/48.jpg)
Neutron Capture
48
![Page 49: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/49.jpg)
General Characteristics
49
• most of captures occur at low energies< 1 MeV
• ~ 1.5 msec time constant
• extends to largi radii ~30-40 cm
![Page 50: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/50.jpg)
Multiplicity of Produced Particles
50
• one or two gammas produced
![Page 51: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/51.jpg)
Spectra of Produced Particles
51
• ~8 MeV single gamma, or two gammas sharing 8 MeV
![Page 52: Physics of Hadron Showers in GEANT4 (progress report)](https://reader036.fdocuments.us/reader036/viewer/2022062719/56813120550346895d978ce9/html5/thumbnails/52.jpg)
Energy Lost
52
• binding energy released as gammas. Effective gain (back) of energy