Difference between revisions of "Bubble Chamber Beam Test May 2018"

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(Created page with "= '''Bubble Chamber Turn On''' = * '''Fill with natural N<sub>2</sub>O – test bubble chamber systems operation''' * '''With beam on bubble chamber radiator:''' # How doe...")
 
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= '''Bubble Chamber Turn On''' =
 
= '''Bubble Chamber Turn On''' =
  
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* '''Fill with natural N<sub>2</sub>O – test bubble chamber systems operation'''
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* '''Fill with natural C<sub>3</sub>F<sub>8</sub>– test bubble chamber systems operation'''
  
  
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# Measure beam on background by looking outside fiducial volume
 
# Measure beam on background by looking outside fiducial volume
 
# Measure background with beam to Faraday Cup in CEBAF beamline (about two meters from chamber)
 
# Measure background with beam to Faraday Cup in CEBAF beamline (about two meters from chamber)
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# Measure neutron events in chamber. Neutron radiation detectors in injector region will indicate if any neutrons are generated (especially at beam kinetic energies higher than 8.5 MeV).
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# Measure neutron events in chamber. Neutron radiation detectors in injector region will indicate if any neutrons are generated (especially at beam kinetic energies higher than 5.5 MeV).
  
  
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= '''Bubble Chamber Beam Test''' =
 
= '''Bubble Chamber Beam Test''' =
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* '''Chamber is filled with natural N<sub>2</sub>O'''
 
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* '''Cross sections:'''
 
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The cross sections are shown in the following figure:
 
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[[file:CrossSections.gif||500px|]]
 
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* '''Expected rates:'''
 
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The expected rates are calculated with 3 cm cell thickness and Bremsstrahlung beam from copper radiator.
 
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* The expected rates are shown in the following figure:
 
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[[file:gNaturalN2O.gif||500px|]]
 
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* The expected rates with the latest data are shown in the following figure:
 
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[[file:gNaturalN2OData.gif||500px|]]
 
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* The expected rates from oxygen isotopes are shown in the following figure:
 
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[[file:gNaturalO.gif||500px|]]
 
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* The expected rate from <sup>14</sup>N(γ,p)<sup>13</sup>C with ThrCut = 50 keV is shown in the following figure:
 
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[[file:g14Np_rate_ThrCut.gif||500px|]]
 
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* Root macros to calculate <sup>14</sup>N(γ,p)<sup>13</sup>C with different threshold cuts (change .txt to .tar): [[media:Rate_14Ngp_ThrCut.txt]]
 
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* <sup>17</sup>O(γ,n)<sup>16</sup>O cross section:
 
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[[file:cs17Ogn_new.gif||500px|]]
 
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* The expected rate from <sup>17</sup>O(γ,n)<sup>16</sup>O is shown in the following figure:
 
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[[file:g17On_rate.gif||500px|]]
 
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* The expected rate from <sup>17</sup>O(γ,n)<sup>16</sup>O with ThrCut = 130 keV is shown in the following figure:
 
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[[file:g17On_rate_ThrCut.gif||500px|]]
 
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* Root macros to calculate <sup>17</sup>O(γ,n)<sup>16</sup>O with different threshold cuts (change .txt to .tar): [[media:Rate_17Ogn_ThrCut.txt]]
 
  
  
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* ''Check if Bubble Chamber is working properly:''
 
* ''Check if Bubble Chamber is working properly:''
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# Start with K.E. of 7.7 MeV
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# Start with K.E. of 5.2 MeV
 
# Determine the initial operational pressure and temperature
 
# Determine the initial operational pressure and temperature
 
# Measure bubble rate. The expected rate is 1 bubble per sec at 10 µA
 
# Measure bubble rate. The expected rate is 1 bubble per sec at 10 µA
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# Measure the number of bubbles for 30 minutes per beam current
 
# Measure the number of bubbles for 30 minutes per beam current
  
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* ''Suppression of <sup>14</sup>N(γ,p)<sup>13</sup>C events:''
 
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# Start with beam at K.E. 7.0 MeV
 
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# Increase beam K.E. by 0.2 MeV steps all the way to 8.6 MeV
 
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# Adjust beam current to maintain a bubble rate of few per minute
 
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# Measure the number of bubbles for 30 minutes per energy
 
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# Reproduce the overall rate shown above
 
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# At K.E. of 8.6 MeV, increase the chamber threshold by increasing the pressure. Suppress the <sup>14</sup>N(γ,p)<sup>13</sup>C events.
 
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# Once <sup>14</sup>N(γ,p)<sup>13</sup>C is suppressed, the rate should drop by three orders of magnitude
 
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* ''Measuring rates from <sup>18</sup>O(γ,α)<sup>14</sup>C:''
 
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# Now the chamber is at the new pressure
 
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# Start with beam at K.E. 7.2 MeV
 
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# Increase beam K.E. by 0.2 MeV steps all the way to 9.2 MeV
 
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# Adjust beam current to maintain a bubble rate of few per minute
 
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# Measure the number of bubbles for 30 minutes per energy
 
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# Reproduce the overall rate from oxygen isotopes shown above
 
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# Note the change in slope of rates vs. beam K.E. and the sharp kink around 7.6 MeV
 
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* ''Measuring <sup>18</sup>O(γ,α)<sup>14</sup>C cross section:''
 
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# Start with beam at K.E. 7.4 MeV
 
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# Increase beam K.E. by 0.1 MeV steps all the way to 8.4 MeV
 
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# Adjust beam current to maintain a bubble rate of few per minute
 
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# Perform Penfold-Leiss unfolding
 
  
  
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The expected yield (counts) is shown in the following figure:
 
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[[file:csO18_Yield_Brem_bg.gif||500px|]]
 
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The Penfold-Leiss unfolded cross section is shown in the following figure:
 
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[[file:csO18_Brem_Unfold_bg.gif||500px|]]
 
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*  Root macro files used to generate the figures above (change .txt to .tar): [[media:BubbleTest_Sept.txt]]
 
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= '''Analysis Files''' =
 
  
 
* '''Presentations'''
 
* '''Presentations'''
  
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* MCC 8 am presentation: [[media:FirstTests.pdf]] [[media:FirstTests.pptx]]
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* MCC 8 am presentation
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* Filling Chamber with nitrous oxide: Movie [https://drive.google.com/file/d/0B9ShTslvnOaCeFplbDU5NjZTSWs/view?usp=sharing]
 
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* MCC 8 am movie first event: [[media:FirstBubble.gif]]
 
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* September 12, 2015 Morning work: [[media:sept12morning.png]]
 
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* September 12, 2015 Morning work: [[media:corrected.png]]
 
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* Events in fiducial volume: [[media:comp.png]]
 
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* '''Beam Current:'''
 
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The following command dumps the archived current readback (-A) from Keithley Picoammeter K6485 to a file:
 
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mySampler -b "2015-09-10 18:00:00" -s 1s -n 14400 IFY5D04K6485dataRead > BubbleCur_Sept10.txt
 
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* Data file of beam current on Bubble Chamber Faraday Cup or Radiator/Dump (September 10, 18:00 - 22:00): [[media:BubbleCur_Sept10.txt]]
 
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* Data file of beam current on Bubble Chamber Radiator/Dump (September 11, 17:00 - 24:00): [[media:BubbleCur_Sept11.txt]]
 
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* Data file of beam current on Bubble Chamber Radiator/Dump (September 12, 9:00 - 24:00): [[media:BubbleCur_Sept12.txt]]
 
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* Data file of beam current on Bubble Chamber Radiator/Dump (September 13, 9:00 - 19:00): [[media:BubbleCur_Sept13.txt]]
 
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* Data file of beam current on Bubble Chamber Radiator/Dump (September 14, 13:00 - 24:00): [[media:BubbleCur_Sept14.txt]]
 
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The following command dumps the archived current readback from BCM0L02 Gigatronics (µA) to a file:
 
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mySampler -b "2015-09-15 15:00:00" -s 1s -n 18000 IBC0L02Current > BubbleCur_Sept15.txt
 
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* Data file of beam current on Bubble Chamber Radiator/Dump (September 15, 15:00 - 20:00): [[media:BubbleCur_Sept15.txt]]
 
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* Data file of beam current on Bubble Chamber Radiator/Dump (September 16, 15:00 - 22:00): [[media:BubbleCur_Sept16.txt]]
 
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* Data file of beam current on Bubble Chamber Radiator/Dump (September 17, 15:00 - 19:00): [[media:BubbleCur_Sept17.txt]]
 
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* '''Beam Energy:'''
 
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The following command dumps the archived data relevant to measuring beam energy to a file:
 
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mySampler -b "2015-09-10 18:00:00" -s 100s -n 6912 R027GSET R027GMES R027PSET R027PMES R028GSET R028GMES R028PSET R028PMES MDL0L02.BDL MDL0L02M > BubbleEne_Sept2015.txt
 
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* Data file for beam energy measurements (September 10, 18:00 - September 18, 18:00): [[media:BubbleEne_Sept2015.txt]]
 
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= '''Logbook: List of Runs''' =
 
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A copy of the paper logbook: [[media:Bubble_Chamber_Sept_2015_Runs_List.pdf]]
 
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='''Things To Do Next'''=
 
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'''No Beam Checklist'''
 
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* Survey and align 5D line
 
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'''Beam Checklist'''
 
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* Calibrate 0L02 BCM
 
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* Quad-center 0L02, 0L02A, 5D00, 5D01 and set BPM SOFs accordingly
 
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* Measure beam position directly after radiator
 

Revision as of 09:44, 2 May 2018

Bubble Chamber Turn On

  • Fill with natural C3F8– test bubble chamber systems operation


  • With beam on bubble chamber radiator:
  1. How does CCD camera perform under beam-on conditions?
  2. Count rates on bubble chamber. Do we get single or multiple bubbles from Bremsstrahlung beam exposure?
  3. Measure gamma ray beam spatial profile as reflected by bubble distribution. Is collimator effective in defining the gamma-ray beam?
  4. Test the bubble chamber laser shutter (gumby shutter)


  • Background measurements:
  1. Measure beam off environmental background in chamber-injector area
  2. Measure beam on background by looking outside fiducial volume
  3. Measure background with beam to Faraday Cup in CEBAF beamline (about two meters from chamber)
  4. Measure neutron events in chamber. Neutron radiation detectors in injector region will indicate if any neutrons are generated (especially at beam kinetic energies higher than 5.5 MeV).



Bubble Chamber Beam Test


Run Plan:


  • Check if Bubble Chamber is working properly:
  1. Start with K.E. of 5.2 MeV
  2. Determine the initial operational pressure and temperature
  3. Measure bubble rate. The expected rate is 1 bubble per sec at 10 µA
  4. Measure rate vs beam current (0.01, 0.1 and 1.0 µA)
  5. Measure the number of bubbles for 30 minutes per beam current


Beam Kinetic Energy (MeV) Beam Current (µA) Time (hour)
7.4 10 10
7.5 10 10
7.6 10 5
7.7 2 5
7.8 2 5
7.9 1 5
8.0 1 5
8.1 0.8 5
8.2 0.4 5
8.3 0.2 5
8.4 0.2 5


  • Presentations
  • MCC 8 am presentation
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