Difference between revisions of "09-08-2016"

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=Study forward detector gamma flash with Pb curtains=
+
=Study forward detector gamma flash =
 +
==with Pb curtains==
 +
 
 
{| border="1"
 
{| border="1"
 
| Run # ||D90 n Rate (Counts/pulse)|| Configuration
 
| Run # ||D90 n Rate (Counts/pulse)|| Configuration
 
|-
 
|-
−
|5302 || || 11.1 MeV , 2 ns pulse width , 450 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is '''DU'''  , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Installed 3rd collimator wall, D30 has one 1/16" thick lead curtain [[File:Rate2nC_5302.png|40px]]
+
|5302 || || 11.1 MeV , 2 ns pulse width , 450 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is '''DU'''  , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Installed 3rd collimator wall, D30 has one 1/16" thick lead curtain [[File:Rate2nC_5302.png|40px]][[File:Run5302_ToF_Histograms.png|40px]]
 
|-
 
|-
−
|5303 || || 11.1 MeV , 2 ns pulse width , 450 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is DU , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Installed 3rd collimator wall, D30 has '''NO'''  lead curtain [[File:Rate2nC_5303.png|40px]]
+
|5303 || || 11.1 MeV , 2 ns pulse width , 450 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is DU , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Installed 3rd collimator wall, D30 has '''NO'''  lead curtain [[File:Rate2nC_5303.png|40px]][[File:Run5303_ToF_Histograms.png|40px]]
 
|-
 
|-
 
|}
 
|}
  
−
=Thorium strip, collimator squeeze down.=
+
 
 +
 
 +
==Shielding & Beam dump impact on gamma flash==
 
{| border="1"
 
{| border="1"
 
| Run # ||D90 n Rate (Counts/pulse)|| Configuration
 
| Run # ||D90 n Rate (Counts/pulse)|| Configuration
 
|-
 
|-
−
|530 || || 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is '''EMPTY'''  , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Installed 3rd collimator wall, D30 has NO thick lead curtain, [[File:Rate2nC_5305.png|40px]]
+
|5300 || || 11.1 MeV , 2 ns pulse width , 450 mA , 200 Hz , Accelerator side collimator open to '''0.2563 cm''', Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is Empty  , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,[[File:Rate2nC_5300.png|40px]][[File:Run5300_ToF_Histograms.png|40px]]
 +
|-
 +
|5301 || || 11.1 MeV , 2 ns pulse width , 450 mA , 200 Hz , Accelerator side collimator open to '0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is Empty  , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand, '''Installed 3rd collimator wall''', removed line of site between D30 and cell wall collimator [[File:Rate2nC_5301.png|40px]][[File:Run5301_ToF_Histograms.png|40px]]
 +
|-
 +
|5305 || || 11.1 MeV , 2 ns pulse width , 300 mA , '''90 Hz''' , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is '''EMPTY'''  , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,'''Removed 3rd collimator wall''', D30 has NO thick lead curtain, [[File:Rate2nC_5305.png|40px]][[File:Run5305_ToF_Histograms.png|40px]]
 +
|-
 +
|5306 || || 11.1 MeV , 2 ns pulse width , 300 mA , '''200 Hz''' , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is EMPTY  , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, [[File:Rate2nC_5306.png|40px]][[File:Run5306_ToF_Histograms.png|40px]]
 +
|-
 +
|5307 || || 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is EMPTY  , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, [[File:Rate2nC_5307.png|40px]][[File:Run5307_ToF_Histograms.png|40px]]
 +
|-
 +
|5308 || || 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is '''~0.5 mm x 7 cm x 4 mm Thorium'''  , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, [[File:Rate2nC_5308.png|40px]][[File:Run5308_ToF_Histograms.png|40px]]
 +
|-
 +
|5312 || || 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is '''EMPTY'''  , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, Install 16" deep x24" wide x 14" high ALuminium photon''' beam dump'''.  Beam upstream side of dump is 37" from wall[[File:Rate2nC_5312.png|40px]][[File:Run5312_ToF_Histograms.png|40px]]
 +
|-
 +
|5313 || || 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is EMPTY  , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, replace aluminium dump with a half lead brick ''' centered on 2" wide beam''' left right[[File:Rate2nC_5313.png|40px]][[File:Run5313_ToF_Histograms.png|40px]]
 +
|-
 +
|5314 || || 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is EMPTY  , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, replace aluminium dump with a half lead brick '''centered 4" from beam''' center [[File:Rate2nC_5314.png|40px]][[File:Run5314_ToF_Histograms.png|40px]]
 
|-
 
|-
−
|530 || || 11.1 MeV , 2 ns pulse width , 450 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is '''~0.5 mm x 7 cm x 4 mm Th''' , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Installed 3rd collimator wall, D30 has NO thick lead curtain [[File:Rate2nC_5305.png|40px]]
+
|5315 || || 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is EMPTY  , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain,  replace aluminium dump with a half lead brick '''centered 2" from beam''' center [[File:Rate2nC_5315.png|40px]][[File:Run5315_ToF_Histograms.png|40px]]
 +
|-
 +
|5316 || || 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is EMPTY , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, replace  half lead brick with battle ship steel 17" high 24" deep and 4" beam left right [[File:Rate2nC_5316.png|40px]][[File:Run5316_ToF_Histograms.png|40px]]
 
|-
 
|-
 
|}
 
|}
 +
 +
== Tuning impact on gamma flash==
 +
 +
We set up a veto to create a signal that represented the second peak of the gamma flash in D270 & others.  A veto pulse was created for the LED to prevent it from outputing a logic high during the first 20 ns after the beam pulse.
 +
 +
 +
{| border="1"
 +
| Run # ||D90 n Rate (Counts/pulse)|| Configuration
 +
|-
 +
|5309 || || 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is '''EMPTY'''  , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, '''Veto OUT'''[[File:Rate2nC_5309.png|40px]][[File:Run5309_ToF_Histograms.png|40px]]
 +
|-
 +
|5310 || || 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is EMPTY  , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, '''Veto IN'''[[File:Rate2nC_5310.png|40px]][[File:Run5310_ToF_Histograms.png|40px]]
 +
|-
 +
|}
 +
 +
=Thorium plate rates.=
 +
 +
{| border="1"
 +
| Run # ||D90 n Rate (Counts/pulse)|| Configuration
 +
|-
 +
|5316 || || 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is '''EMPTY'''  , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, replace  half lead brick with battle ship steel 17" high 24" deep and 4" beam left right [[File:Rate2nC_5316.png|40px]][[File:Run5316_ToF_Histograms.png|40px]]
 +
|-
 +
|5317 || || 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is '''Thorium plate''' orthogonal to beam (90)  , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, replace  half lead brick with battle ship steel 17" high 24" deep and 4" beam left right [[File:Rate2nC_5317.png|40px]][[File:Run5317_ToF_Histograms.png|40px]]
 +
|-
 +
|5318 || || 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator wide open '''to 8 mm slit''', Cell side collimator '''OPEN to 7.5 cm''' , radiator 3/4" IN , Target is Thorium plate orthogonal to beam (90)  , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, replace  half lead brick with battle ship steel 17" high 24" deep and 4" beam left right [[File:Rate2nC_5318.png|40px]][[File:Run5318_ToF_Histograms.png|40px]]
 +
|-
 +
|5319 || || 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator wide open to 8 mm slit, Cell side collimator OPEN to 7.5 cm , radiator '''1.5" IN''' , Target is Thorium plate orthogonal to beam (90)  , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, replace  half lead brick with battle ship steel 17" high 24" deep and 4" beam left right [[File:Rate2nC_5319.png|40px]][[File:Run5319_ToF_Histograms.png|40px]]
 +
|-
 +
|5320 || || 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator wide open to 8 mm slit, Cell side collimator OPEN to 7.5 cm , radiator 1.5" IN , Target is '''EMPTY''' , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, replace  half lead brick with battle ship steel 17" high 24" deep and 4" beam left right [[File:Rate2nC_5320.png|40px]][[File:Run5320_ToF_Histograms.png|40px]]
 +
|-
 +
|5321 || || 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator wide open to 8 mm slit, Cell side collimator OPEN to 7.5 cm , radiator 1.5" IN , Target is '''Thorium plate''' orthogonal to beam (90)  , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, replace  half lead brick with battle ship steel 17" high 24" deep and 4" beam left right [[File:Rate2nC_5321.png|40px]][[File:Run5321_ToF_Histograms.png|40px]] Target in minus target out -> [[File:TargetInMinusOut(runs5321and5320).png|60px]]
 +
|-
 +
|5322 || || 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator wide open to 8 mm slit, Cell side collimator OPEN to 7.5 cm , radiator 1.5" IN , Target is '''Empty''' orthogonal to beam (90)  , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, replace  half lead brick with battle ship steel 17" high 24" deep and 4" beam left right [[File:Rate2nC_5322.png|40px]][[File:Run5322_ToF_Histograms.png|40px]]
 +
|-
 +
|5323 || || 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator wide open to 8 mm slit, Cell side collimator OPEN to 7.5 cm , radiator 1.5" IN , Target is '''Empty''' orthogonal to beam (90)  , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, replace  half lead brick with battle ship steel 17" high 24" deep and 4" beam left right, 1" Al brick on end to have 4" of Al at exit of tunnel of love [[File:Rate2nC_5323.png|40px]][[File:Run5323_ToF_Histograms.png|40px]]
 +
 +
|}
 +
 +
=End of Run summary=
 +
 +
#The back wall was a source of photons that can be reduced best with blinders
 +
#The ToF spectrum needs better separation between gamma flash and neutrons, Move detectors back?
 +
#The tunnel of love reduced the photon singles rate by about 10% for D120 & D150 (compare runs 5300 & 5301).
 +
#Opening the collimator slit fully caused gamma flash to appear close to the neutron ToF
 +
#Neutron singles rate in D225 was within the desired rate of 2e-3 n/pulse for a thorium plate target at 90 degrees to the beam
 +
#D30's rate decreases by a factor of three for every inch of lead shielding added to the front
 +
#pair spectrometer magnet has little impact on detector background
 +
#beam tuning may increase photon flash.
 +
#determine collimator size to produce photon cone that is contained within the photon dump (blinders)
 +
#cleanup collimator inside wall separating accelerator room and experimental cell
  
 
=No target run=
 
=No target run=
Line 27: Line 99:
 
= Long run on Thorium=
 
= Long run on Thorium=
 
= Long run on 1 mg HEU=
 
= Long run on 1 mg HEU=
 +
 +
=Pictures=
 +
[[Pictures(09-09-2016)]]
  
 
[[2nCor_44#Run_Plan]]
 
[[2nCor_44#Run_Plan]]

Latest revision as of 20:58, 27 September 2016

Study forward detector gamma flash

with Pb curtains

Run # D90 n Rate (Counts/pulse) Configuration
5302 11.1 MeV , 2 ns pulse width , 450 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is DU , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Installed 3rd collimator wall, D30 has one 1/16" thick lead curtain Rate2nC 5302.png40px
5303 11.1 MeV , 2 ns pulse width , 450 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is DU , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Installed 3rd collimator wall, D30 has NO lead curtain Rate2nC 5303.png40px


Shielding & Beam dump impact on gamma flash

Run # D90 n Rate (Counts/pulse) Configuration
5300 11.1 MeV , 2 ns pulse width , 450 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is Empty , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Rate2nC 5300.png40px
5301 11.1 MeV , 2 ns pulse width , 450 mA , 200 Hz , Accelerator side collimator open to '0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is Empty , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand, Installed 3rd collimator wall, removed line of site between D30 and cell wall collimator Rate2nC 5301.png40px
5305 11.1 MeV , 2 ns pulse width , 300 mA , 90 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is EMPTY , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, Rate2nC 5305.pngRun5305 ToF Histograms.png
5306 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is EMPTY , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, Rate2nC 5306.pngRun5306 ToF Histograms.png
5307 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is EMPTY , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, Rate2nC 5307.pngRun5307 ToF Histograms.png
5308 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is ~0.5 mm x 7 cm x 4 mm Thorium , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, Rate2nC 5308.pngRun5308 ToF Histograms.png
5312 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is EMPTY , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, Install 16" deep x24" wide x 14" high ALuminium photon beam dump. Beam upstream side of dump is 37" from wallRate2nC 5312.pngRun5312 ToF Histograms.png
5313 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is EMPTY , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, replace aluminium dump with a half lead brick centered on 2" wide beam left rightRate2nC 5313.pngRun5313 ToF Histograms.png
5314 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is EMPTY , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, replace aluminium dump with a half lead brick centered 4" from beam center Rate2nC 5314.pngRun5314 ToF Histograms.png
5315 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is EMPTY , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, replace aluminium dump with a half lead brick centered 2" from beam center Rate2nC 5315.pngRun5315 ToF Histograms.png
5316 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is EMPTY , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, replace half lead brick with battle ship steel 17" high 24" deep and 4" beam left right Rate2nC 5316.pngRun5316 ToF Histograms.png

Tuning impact on gamma flash

We set up a veto to create a signal that represented the second peak of the gamma flash in D270 & others. A veto pulse was created for the LED to prevent it from outputing a logic high during the first 20 ns after the beam pulse.


Run # D90 n Rate (Counts/pulse) Configuration
5309 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is EMPTY , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, Veto OUT40px40px
5310 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is EMPTY , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, Veto IN40px40px

Thorium plate rates.

Run # D90 n Rate (Counts/pulse) Configuration
5316 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is EMPTY , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, replace half lead brick with battle ship steel 17" high 24" deep and 4" beam left right Rate2nC 5316.pngRun5316 ToF Histograms.png
5317 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator open to 0.2563 cm, Cell side collimator OPEN to 2 cm , radiator 3/4" IN , Target is Thorium plate orthogonal to beam (90) , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, replace half lead brick with battle ship steel 17" high 24" deep and 4" beam left right Rate2nC 5317.pngRun5317 ToF Histograms.png
5318 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator wide open to 8 mm slit, Cell side collimator OPEN to 7.5 cm , radiator 3/4" IN , Target is Thorium plate orthogonal to beam (90) , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, replace half lead brick with battle ship steel 17" high 24" deep and 4" beam left right Rate2nC 5318.pngRun5318 ToF Histograms.png
5319 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator wide open to 8 mm slit, Cell side collimator OPEN to 7.5 cm , radiator 1.5" IN , Target is Thorium plate orthogonal to beam (90) , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, replace half lead brick with battle ship steel 17" high 24" deep and 4" beam left right Rate2nC 5319.pngRun5319 ToF Histograms.png
5320 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator wide open to 8 mm slit, Cell side collimator OPEN to 7.5 cm , radiator 1.5" IN , Target is EMPTY , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, replace half lead brick with battle ship steel 17" high 24" deep and 4" beam left right Rate2nC 5320.pngRun5320 ToF Histograms.png
5321 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator wide open to 8 mm slit, Cell side collimator OPEN to 7.5 cm , radiator 1.5" IN , Target is Thorium plate orthogonal to beam (90) , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, replace half lead brick with battle ship steel 17" high 24" deep and 4" beam left right Rate2nC 5321.pngRun5321 ToF Histograms.png Target in minus target out -> TargetInMinusOut(runs5321and5320).png
5322 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator wide open to 8 mm slit, Cell side collimator OPEN to 7.5 cm , radiator 1.5" IN , Target is Empty orthogonal to beam (90) , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, replace half lead brick with battle ship steel 17" high 24" deep and 4" beam left right Rate2nC 5322.pngRun5322 ToF Histograms.png
5323 11.1 MeV , 2 ns pulse width , 300 mA , 200 Hz , Accelerator side collimator wide open to 8 mm slit, Cell side collimator OPEN to 7.5 cm , radiator 1.5" IN , Target is Empty orthogonal to beam (90) , D30 HV changed -1550V, All other detectors at -1700 V, removed pair spectrometer magnet, poly, and stand,Removed 3rd collimator wall, D30 has NO thick lead curtain, replace half lead brick with battle ship steel 17" high 24" deep and 4" beam left right, 1" Al brick on end to have 4" of Al at exit of tunnel of love Rate2nC 5323.pngRun5323 ToF Histograms.png

End of Run summary

  1. The back wall was a source of photons that can be reduced best with blinders
  2. The ToF spectrum needs better separation between gamma flash and neutrons, Move detectors back?
  3. The tunnel of love reduced the photon singles rate by about 10% for D120 & D150 (compare runs 5300 & 5301).
  4. Opening the collimator slit fully caused gamma flash to appear close to the neutron ToF
  5. Neutron singles rate in D225 was within the desired rate of 2e-3 n/pulse for a thorium plate target at 90 degrees to the beam
  6. D30's rate decreases by a factor of three for every inch of lead shielding added to the front
  7. pair spectrometer magnet has little impact on detector background
  8. beam tuning may increase photon flash.
  9. determine collimator size to produce photon cone that is contained within the photon dump (blinders)
  10. cleanup collimator inside wall separating accelerator room and experimental cell

No target run

Determine how many fissions per pulse.

run 1 mg HEU to see (probably miserable) rates

Exploratory measurements with 47% HEU.

CFD studies

P.S. sweep magnet in/out

Long run on Thorium

Long run on 1 mg HEU

Pictures

Pictures(09-09-2016)

2nCor_44#Run_Plan

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