Difference between revisions of "D2O data"

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Two thicknesses of Al brem radiator were used (A) 10 um for 10% of the beam time, (B) 25 um for 90% of the beam time.
 
Two thicknesses of Al brem radiator were used (A) 10 um for 10% of the beam time, (B) 25 um for 90% of the beam time.
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==Relative photon flux monitoring. Beam UP==
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[[File:flux_2527_D2O_UP.png | 400 px]]
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[[File:flux_2535_D2O_UP.png | 400 px]]
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[[File:flux_2536_D2O_UP.png | 400 px]]
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[[File:flux_2539_D2O_UP.png | 400 px]]
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[[File:flux_2544_D2O_UP.png | 400 px]]
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[[File:flux_2552_D2O_UP.png | 400 px]]
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[[File:flux_2554_D2O_UP.png | 400 px]]
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The total beam time for the D2O target beam UP configuration was 13080 sec and total relative photon flux during that time expressed in the number of positrons was 76677 <math>e^+</math>
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==Relative photon flux monitoring. Beam DOWN==
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[[File:flux_2530_D2O_DOWN.png | 400 px]]
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[[File:flux_2537_D2O_DOWN.png | 400 px]]
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[[File:flux_2541_D2O_DOWN.png | 400 px]]
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[[File:flux_2542_D2O_DOWN.png | 400 px]]
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[[File:flux_2555_D2O_DOWN.png | 400 px]]
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[[File:flux_2556_D2O_DOWN.png | 400 px]]
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The total beam time for the D2O target beam DOWN configuration was 12540 sec and total relative photon flux during that time expressed in the number of positrons was 71557 <math>e^+</math>
  
 
==Beam UP configuration==
 
==Beam UP configuration==
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[[File:D2O_de_nene_cumul_UP.png | 800 px]]
 
[[File:D2O_de_nene_cumul_UP.png | 800 px]]
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==Beam DOWN configuration==
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Cumulative raw ToF spectra obteined for the case of D2O target and beam DOWN position are presented below:
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[[File:D2O_raw_cumul_DOWN.png | 800 px]]
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The width of the photon peak (sigma) shows the IAC linac pulse width at it was mentioned above it was around 2 ns.
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Neutron energy spectra reonstructed from the ToF spectra for the beam DOWN and D2O are shown below:
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[[File:D2O_nene_cumul_DOWN.png | 800 px]]
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The neutron detectors was placed azimuthally symmetric around the target so the distance was 135.5 cm from the center of the target to the face of each of the detector.
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The uncertainty on the neutron energy depends mostly on the knowledge of the photon peak center position. The width of the photon peak gives an uncertainty in the neutron energy.
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 +
The energy uncertainty for the beam DOWN and D2O target are shown below:
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[[File:D2O_de_nene_cumul_DOWN.png | 800 px]]
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==Polarization==
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The sum of the number of neutrons in three detectors placed at 0 deg left, 90 deg bottom and 0 deg right was used to do the narmalization for both beam UP and DOWN configurations, i.e. the procedure that takes into account possible photon flux change. For the justification of the normalization procedure see [https://wiki.iac.isu.edu/index.php/Photon_flux_proportionality]
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[[File:D2O_polarization_degree.png | 600 px]]

Latest revision as of 20:28, 11 June 2013

Beam parameters:

Current ~ 160 mA

Pulse width ~ 2 ns

Rep rate ~ 180 Hz

Electron energy ~ 25 MeV

Two thicknesses of Al brem radiator were used (A) 10 um for 10% of the beam time, (B) 25 um for 90% of the beam time.

Relative photon flux monitoring. Beam UP

Flux 2527 D2O UP.png

Flux 2535 D2O UP.png

Flux 2536 D2O UP.png

Flux 2539 D2O UP.png

Flux 2544 D2O UP.png

Flux 2552 D2O UP.png

Flux 2554 D2O UP.png

The total beam time for the D2O target beam UP configuration was 13080 sec and total relative photon flux during that time expressed in the number of positrons was 76677 [math]e^+[/math]

Relative photon flux monitoring. Beam DOWN

Flux 2530 D2O DOWN.png

Flux 2537 D2O DOWN.png

Flux 2541 D2O DOWN.png

Flux 2542 D2O DOWN.png

Flux 2555 D2O DOWN.png

Flux 2556 D2O DOWN.png

The total beam time for the D2O target beam DOWN configuration was 12540 sec and total relative photon flux during that time expressed in the number of positrons was 71557 [math]e^+[/math]

Beam UP configuration

Cumulative raw ToF spectra obteined for the case of D2O target and beam up position are presented below:

D2O raw cumul UP.png

The width of the photon peak (sigma) shows the IAC linac pulse width which we've been told was around 2 ns.

Neutron energy spectra reonstructed from the ToF spectra for the beam UP and D2O are shown below:

D2O nene cumul UP.png

The neutron detectors was placed azimuthally symmetric around the target so the distance was 135.5 cm from the center of the target to the face of each of the detector.

The uncertainty on the neutron energy depends mostly on the knowledge of the photon peak center position. The width of the photon peak gives an uncertainty in the neutron energy. .

The energy uncertainty for the beam UP and D2O target are shown below:

D2O de nene cumul UP.png


Beam DOWN configuration

Cumulative raw ToF spectra obteined for the case of D2O target and beam DOWN position are presented below:

D2O raw cumul DOWN.png

The width of the photon peak (sigma) shows the IAC linac pulse width at it was mentioned above it was around 2 ns.

Neutron energy spectra reonstructed from the ToF spectra for the beam DOWN and D2O are shown below:

D2O nene cumul DOWN.png

The neutron detectors was placed azimuthally symmetric around the target so the distance was 135.5 cm from the center of the target to the face of each of the detector.

The uncertainty on the neutron energy depends mostly on the knowledge of the photon peak center position. The width of the photon peak gives an uncertainty in the neutron energy.

The energy uncertainty for the beam DOWN and D2O target are shown below:

D2O de nene cumul DOWN.png

Polarization

The sum of the number of neutrons in three detectors placed at 0 deg left, 90 deg bottom and 0 deg right was used to do the narmalization for both beam UP and DOWN configurations, i.e. the procedure that takes into account possible photon flux change. For the justification of the normalization procedure see [1]

D2O polarization degree.png

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