2-Neutron Correlation Setup Stuff - Revision history

Swanjase at 15:42, 11 July 2012

2012-07-11T15:42:36Z

Swanjase at 18:35, 8 June 2012

2012-06-08T18:35:44Z

Swanjase: Created page with '== Big Detector Solid Angle Calculations == ; MCNPX Simulation
* 14 MeV neutron source, emitted isotropically ( $4\pi$ )
* Detector placed 1m away from sou…'

2012-06-08T18:35:10Z

Created page with '== Big Detector Solid Angle Calculations == ; MCNPX Simulation * 14 MeV neutron source, emitted isotropically (<math>4\pi</math>) * Detector placed 1m away from sou…'

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== Big Detector Solid Angle Calculations ==

; MCNPX Simulation 
* 14 MeV neutron source, emitted isotropically (<math>4\pi</math>) 
* Detector placed 1m away from source 
[[File:mcnpxsetup.png | 500px]]

* face of the detector is 15.24cm x 76.2cm, and 3.6cm deep 
[[File:DetectorDimensions.png | 500px]]

The solid angle can be found from the number of particles hitting the detector as: 
<math>\Delta \Omega = 4\pi*\frac{hits}{hits + misses}</math>

; Results
* Out of 1E9 neutrons generated, 8618287 neutrons hit the detector
** <math>\Delta \Omega = 0.108 Sr</math>
*** if the detector is placed 70cm away from the source, <math>\Delta \Omega = 0.207 Sr</math>
*** if the detector is placed 65cm away from the source, <math>\Delta \Omega = 0.236 Sr</math>

* As a test to verify our results
** We change the detector size to 2cm by 2cm and used 1E9 neutrons again
** 32061 neutrons struck the detector
** <math>\Delta \Omega = 0.0004 Sr</math>

* And, as a second test to verify our results
** We change the detector size to 1cm by 1cm and used 1E9 neutrons again
** 7965 neutrons struck the detector
** <math>\Delta \Omega = 0.0001 Sr</math>

; Now, what neutron singles rate into the detector should correspond to 1 fission per pulse?
* If we have 1 fission per pulse and each fission emits on average 2.3 neutrons, we should expect 2.3 neutrons/pulse
* The number of neutrons hitting the detector per pulse is found as <math>2.3*\frac{\Delta \Omega}{4\pi}</math>
** @ 1 meter => 0.0198 neutrons hitting the detector per pulse
** @ 70 cm => 0.0379 neutrons hitting the detector per pulse
* Taking into account the efficiency of the detector <math>\epsilon_0</math>, the number detected per pulse can be found as <math>2.3*\frac{\Delta \Omega}{4\pi}*\epsilon_0</math>
** @ 1 meter from source => (<math>0.0198*\epsilon_0=0.0198*0.17=0.003</math>) neutrons detected per pulse
** @ 70 cm from source => (<math>0.0379*\epsilon_0=0.0379*0.17=0.006</math>) neutrons detected per pulse

==Neutron and Photon Flux Through Lead==

Using MCNPX, a simulation was done to determine how much of the neutrons and photons from the target will be blocked by various thickness of lead. With a monochromatic pencil beam of incident particles, the following results illustrate how much of the initial beam actually made it through the lead.

[[File:1MeV_Lead.jpg | 600px]]

[[File:5MeV_Lead.jpg | 600px]]

==Neutron and Photon Flux Through Concrete==

[[File:1MeV_Concrete.jpg | 600px]]

[Go Back]

← Older revision		Revision as of 15:42, 11 July 2012
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	[[File:1MeV_Concrete.jpg \| 600px]]		[[File:1MeV_Concrete.jpg \| 600px]]
		+
		+	== Detector Cross-Talk ==
		+
		+	Using MCNPX, I am trying to simulated the cross-talk we could expect between the big detectors. I used a fission neutron energy spectrum given in MCNPX, shown below.
		+
		+	[[File:FissionNeutronEnergySpectrum.jpg \| 800px]]
		+
		+	These neutrons are incident upon a plastic scintillator and I will look at the neutrons and photons coming out of the scintillator's sides perpendicular to the incident beam. The first case I will look at is where the detectors are placed with only polyethylene between them, as illustrated below.
		+
		+	[[File:OLead.png \| 400px]]
		+
		+	This results in a neutron and photon energy spectrum as follows.
		+
		+	[[File:NeutronEnergySpectrum.jpg \| 800px]]
		+
		+	[[File:PhotonEnergySpectrum.jpg \| 800px]]
		+
		+	The next case I will look at is where we put a layer of lead between the polyethylene between the detectors, as shown in the schematic below.
		+
		+	[[File:DetectorSetupwLead.png \| 400px]]
		+
		+	The results for this setup using 1 inch of lead between the detectors is as follows.
		+
		+	[[File:NeutronEnergySpectrumPb.jpg \| 800px]]
		+
		+	[[File:PhotonEnergySpectrum1inPb.jpg \| 800px]]
		+
		+	And, the results for this setup using 2 inches of lead between the detectors is as follows.
		+
		+	[[File:NeutronEnergySpectrum2Pb.jpg \| 800px]]
		+
		+	[[File:PhotonEnergySpectrum2Pb.jpg \| 800px]]
		+

	[https://wiki.iac.isu.edu/index.php/PhotoFission_with_Polarized_Photons_from_HRRL Go Back]		[https://wiki.iac.isu.edu/index.php/PhotoFission_with_Polarized_Photons_from_HRRL Go Back]

← Older revision		Revision as of 18:35, 8 June 2012
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	[[File:1MeV_Concrete.jpg \| 600px]]		[[File:1MeV_Concrete.jpg \| 600px]]

−	[Go Back]	+	[https://wiki.iac.isu.edu/index.php/PhotoFission_with_Polarized_Photons_from_HRRL Go Back]

2-Neutron Correlation Setup Stuff - Revision history

Swanjase at 15:42, 11 July 2012

Swanjase at 18:35, 8 June 2012

Swanjase: Created page with '== Big Detector Solid Angle Calculations == ; MCNPX Simulation * 14 MeV neutron source, emitted isotropically (4\pi) * Detector placed 1m away from sou…'

Swanjase: Created page with '== Big Detector Solid Angle Calculations == ; MCNPX Simulation
* 14 MeV neutron source, emitted isotropically ( $4\pi$ )
* Detector placed 1m away from sou…'