Difference between revisions of "Absolute Beam Energy"

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(Created page with "==Summary Table== ====Table 1 <ref name="Dowell"/> ==== Properties of metal photocathodes. {| class="wikitable" |- ! Metal Cathodes ! Wavelength & Energy: ''λ<sub>opt</sub>''...")
 
 
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==Summary Table==
+
= '''Summary of Beam Properties in JLab Injector''' =
  
−
 
−
====Table 1 <ref name="Dowell"/> ====
 
−
Properties of metal photocathodes.
 
  
 
{| class="wikitable"
 
{| class="wikitable"
 
|-
 
|-
−
! Metal Cathodes
+
| '''Beam Kinetic Energy, T (MeV)'''
−
! Wavelength & Energy: ''λ<sub>opt</sub>'' (nm), ℏω (eV)
+
|  3.0 – '''9.0'''  
−
! Quantum Efficiency (electrons per photon)
 
−
! Vacuum for 1000h operation (Torr)
 
−
! Work Function, ''φw'' (eV)
 
−
! Thermal Emittance (microns / mm(rms)) Eq. (1)
 
−
! Thermal Emittance (microns / mm(rms)) Expt.
 
−
|-
 
−
| '''Bare Metal'''
 
−
|
 
−
|
 
−
|
 
−
|
 
−
|
 
−
|-
 
−
| Cu
 
−
| 250, 4.96
 
−
| 1.4 x 10<sup>-4</sup>
 
−
| 10<sup>-9</sup>
 
−
| 4.6 <ref name="Sommer1"/>
 
−
|0.5
 
−
|1.0 &plusmn; 0.1 <ref name="Graves"/>
 
−
|-
 
−
|
 
−
|
 
−
|
 
−
|
 
−
|
 
−
|
 
−
| 1.2 &plusmn; 0.2 <ref name="Schmerge"/>
 
 
|-
 
|-
−
|  
+
| '''Beam Current (µA)'''
−
|  
+
| 0.01 – 100
−
|
 
−
|
 
−
|
 
−
|
 
−
| 0.9 &plusmn; 0.05 <ref name="Ding"/>
 
 
|-
 
|-
−
| Mg
+
| '''Absolute Beam Energy'''
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| 266, 4.66
+
| '''0.36%'''
−
| 6.4 x 10<sup>-4</sup>
+
|-  
−
| 10<sup>-10</sup>
+
| '''Relative Beam Energy'''
−
| 3.6 <ref name="Michaelides"/>
+
| '''0.1%'''
−
| 0.8
 
−
| 0.4 &plusmn; 0.1 <ref name="Michaelides"/>
 
 
|-
 
|-
−
| Pb
+
| '''Energy Resolution (Spread), σ<sub>T</sub> /T'''
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| 250 , 4.96
+
| 0.2%
−
| 6.9 x 10<sup>-4</sup>
 
−
| 10<sup>-9</sup>
 
−
| 4.0 <ref name="Sommer1"/>
 
−
| 0.8
 
−
| ?
 
 
|-
 
|-
−
| Nb
+
| '''Beam Size, σ<sub>x,y</sub> (mm)'''
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| 250 , 4.96
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| 1 – 2  
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| ~2 x 10<sup>-5</sup>
 
−
| 10<sup>-10</sup>
 
−
| 4.38 <ref name="Sommer1"/>
 
−
| 0.6
 
−
| ?
 
−
|-
 
−
| '''Coated Metal'''
 
−
|
 
−
|
 
−
|
 
−
|
 
−
|
 
−
|-
 
−
| CsBr:Cu
 
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| 250 , 4.96
 
−
| 7 x 10<sup>-3</sup>
 
−
| 10<sup>-9</sup>
 
−
| ~2.5
 
−
| ?
 
−
| ?
 
−
|-
 
−
| CsBr:Nb
 
−
| 250 , 4.96
 
−
| 7 x 10<sup>-3</sup>
 
−
| 10<sup>-9</sup>
 
−
| ~2.5
 
−
| ?
 
−
| ?
 
 
|}
 
|}
  
−
The thermal emittances are computed using the listed photon and work function energies in Eq. (1) and express the thermal emittance as the normalized rms emittance in microns per laser size in mm. The known experimental emittances are given with references.
+
Goal:
 +
  - Reduce the uncertainty on the absolute beam energy to '''<0.1%''' and achieve a relative beam energy of '''<0.02%'''.
  
−
====Table 2 <ref name="Dowell"/>====
 
  
  
−
Properites of semiconductor cathodes.
+
= '''Mott Results''' =
 +
* J. Grames, "Mott Experiment Run I/II Beam Energies" JLAB-TN-17-001 (Jan 17, 2017) [[media:JLAB-TN-17-001.docx]] [[media:JLAB-TN-17-001.pdf]]
  
−
{| class="wikitable"
 
−
|-
 
−
! Cathode Type
 
−
! Cathode
 
−
! Typical Wavelength & Energy, &lambda;<sub>opt</sub> (nm), (eV)
 
−
! Quantum Efficiency (electrons per photon)
 
−
! Vacuum for 1000 h (Torr)
 
−
! Gap Energy + Electron Affinity, E<sub>G</sub>+E<sub>A</sub> (eV)
 
−
! Thermal Emittance (microns / mm(rms)) Eq. (2)
 
−
! Thermal Emittance (microns / mm(rms)) Expt.
 
−
|-
 
−
| '''PEA: mono-alkali'''
 
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| Cs<sub>2</sub>Te
 
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| 211, 5.88
 
−
| 0.1
 
−
| 10<sup>-9</sup>
 
−
| 3.5 <ref name="Sommer2"/>
 
−
| 1.2
 
−
| 0.5 &plusmn; 0.1 <ref name="Sertore"/>
 
−
|-
 
−
|
 
−
|
 
−
| 262, 4.70
 
−
| -
 
−
| -
 
−
| "
 
−
| 0.9
 
−
| 0.7 &plusmn; 0.1 <ref name="Sertore"/>
 
−
|-
 
−
|
 
−
|
 
−
| 262, 4.73
 
−
| -
 
−
| -
 
−
| "
 
−
| 0.9
 
−
| 1.2 &plusmn; 0.1 <ref name="Miltchev"/>
 
−
|-
 
−
|
 
−
| Cs<sub>3</sub>Sb
 
−
| 432, 2.87
 
−
| 0.15
 
−
| ?
 
−
| 1.6 + 0.45 <ref name="Sommer2"/>
 
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| 0.7
 
−
| ?
 
−
|-
 
−
|
 
−
| K<sub>3</sub>Sb
 
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| 400, 3.10
 
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| 0.07
 
−
| ?
 
−
| 1.1 + 1.6 <ref name="Sommer2"/>
 
−
| 0.5
 
−
| ?
 
−
|-
 
−
|
 
−
| Na<sub>3</sub>
 
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| 330, 3.76
 
−
| 0.02
 
−
| ?
 
−
| 1.1 + 1.6 <ref name="Sommer2"/>
 
−
| 0.4
 
−
| ?
 
−
|-
 
−
|
 
−
| Li<sub>3</sub>Sb
 
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| 295, 4.20
 
−
| 0.0001
 
−
| ?
 
−
| ?
 
−
| ?
 
−
| ?
 
−
|-
 
−
| '''PEA: multi-alkali'''
 
−
| Na<sub>2</sub>KSb
 
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| 330, 3.76
 
−
| 0.1
 
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| 10<sup>-10</sup>
 
−
| 1 + 1 <ref name="Sommer2"/>
 
−
| 1.1
 
−
| ?
 
−
|-
 
−
|
 
−
| (Cs)Na<sub>3</sub>KSb
 
−
| 390, 3.18
 
−
| 0.2
 
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| 10<sup>-10</sup>
 
−
| 1 + 0.55 <ref name="Sommer2"/>
 
−
| 1.5
 
−
| ?
 
−
|-
 
−
|
 
−
| K<sub>2</sub>CsSb
 
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| 543, 2.28
 
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| 0.1
 
−
| 10<sup>-10</sup>
 
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| 1+1.1 <ref name="Sommer2"/>
 
−
| 0.4
 
−
| ?
 
−
|-
 
−
|
 
−
|
 
−
| 532
 
−
|
 
−
|
 
−
|
 
−
|
 
−
| 0.56 &plusmn; 0.03 <ref name="Bazarov3"/>
 
−
|-
 
−
|
 
−
| K<sub>2</sub>CsSb(O)
 
−
| 543, 2.28
 
−
| 0.1
 
−
| 10<sup>-10</sup>
 
−
| 1 + <1.1 <ref name="Sommer2"/>
 
−
| ~0.4
 
−
| ?
 
−
|-
 
−
| '''NEA'''
 
−
| GaAs(Cs,F)
 
−
| 532, 2.33
 
−
| 0.1
 
−
| ?
 
−
| 1.4 &plusmn; 0.1 <ref name="Sommer2"/>
 
−
| 0.8
 
−
| 0.44 &plusmn; 0.01 <ref name="Bazarov1"/>
 
−
|-
 
−
|
 
−
|
 
−
| 860, 1.44
 
−
| 0.1
 
−
| ?
 
−
|
 
−
| 0.2
 
−
| 0.22 &plusmn; 0.01 <ref name="Bazarov1"/>
 
−
|-
 
−
|
 
−
| GaN(Cs)
 
−
| 260, 4.77
 
−
| 0.1
 
−
| ?
 
−
| 1.96 + ? <ref name="Bazarov1"/>
 
−
| 1.35
 
−
| 1.35 &plusmn; 0.1 <ref name="Bazarov2"/>
 
−
|-
 
−
|
 
−
| GaAs(1-x)Px ''x''~0.45 (Cs,F)
 
−
| 532, 2.33
 
−
| 0.1
 
−
| ?
 
−
| 1.96 + ? <ref name="Bazarov1"/>
 
−
| 0.49
 
−
| 0.44 &plusmn; 0.1 <ref name="Bazarov1"/>
 
−
|-
 
−
| '''S-1'''
 
−
| Ag-O-Cs
 
−
| 900, 1.38
 
−
| 0.01
 
−
| ?
 
−
| 0.7 <ref name="Sommer2"/>
 
−
| 0.7
 
−
| ?
 
−
|}
 
  
−
The thermal emittances are computed using the listed photon, gap and electron affinity energies in Eq. (2) and express the thermal emittance as the normalized rms emittance in microns per rms laser size in mm.
+
 
 +
= '''Dipole Field'''=
 +
* ''MDL0L02 Dipole and Environmental Fields'', August 16, 2016: [[media:MDL_Environmental_Fields.pdf]] [[media:MDL_Environmental_Fields.pptx]]
 +
* ''MDL0L02 Dipole Hysteresis Loop Study'', September 20, 2016: [[media:MDL_HysLoopMap.pdf]] [[media:MDL_HysLoopMap.pptx]]
 +
* New Field Map: [[media:FinalNewMDL0L02_fm.txt]]
 +
 
 +
 
 +
 
 +
= '''New Dipole Magnet''' =
 +
# Magnet Design: [[media:new_5MeV_dipole.pdf]] [[media:new_5MeV_dipole.doc]]
 +
# Magnet Drawings (change txt to tar): [[media:05-06-14_ISSUED_DL_MAG_DRAWINGS.txt]]
 +
# ''A detailed examination of the MDL field map and the TOSCA model of this "5 MeV" dipole''
 +
Jay Benesch (JLab Tech note 15-017, September 9, 2015): [[media:TN-15-017_MDL_FieldMap.pdf]] [[media:Graphs_MDL.pdf]] [[media:Graphs_MDL.docx]]
 +
 
 +
 
 +
 
 +
= '''New Hall Probe''' =
 +
# GMW DTM-151-PS Digital Teslameter, 20 Bit Resolution, RS-232 Interface, Panel Mtg [[media:G3_MAN_DTM-151-S.pdf]]
 +
# GMW MPT-231-8s Miniature Hall Probe with thermal sensor, High Sensitivity 0.03T, 0.06T, 0.12T, & 0.3T, 8m shielded cable. 0.01% accuracy, resolution to 2 ppm, and a temperature stability of 10 ppm/°C.
 +
 
 +
 
 +
 
 +
= '''PEPPo Results''' =
 +
 
 +
==Momentum Measurement:==
 +
 
 +
* Joe's summary of beam momentum: [[Media:130724_Bubble_Grames.pdf]]
 +
* Joe's presentation at PEPPo Collaboration Meeting: [[Media:Collab_Momentum_Grames.pdf]]
 +
* Joe's followup: [[Media:130718_FollowUp_Momentum_Grames.pdf]]
 +
* Joe's followup: BPM quad centering [[Media:130726_MomentumFollowUp2_Grames.pdf]]
 +
 
 +
==Cryounit Gradient:==
 +
 
 +
* ''Upper limit of the electron beam energy at the CEBAF 2D injector spectrometer and its functionality''
 +
Jonathan Dumas, Joe Grames, and Eric Voutier [[Media:JLAB-TN-08-086.pdf]]

Latest revision as of 08:52, 13 April 2018

Summary of Beam Properties in JLab Injector

Beam Kinetic Energy, T (MeV) 3.0 – 9.0
Beam Current (µA) 0.01 – 100
Absolute Beam Energy 0.36%
Relative Beam Energy 0.1%
Energy Resolution (Spread), σT /T 0.2%
Beam Size, σx,y (mm) 1 – 2 
Goal:
 - Reduce the uncertainty on the absolute beam energy to <0.1% and achieve a relative beam energy of <0.02%.


Mott Results


Dipole Field


New Dipole Magnet

  1. Magnet Design: media:new_5MeV_dipole.pdf media:new_5MeV_dipole.doc
  2. Magnet Drawings (change txt to tar): media:05-06-14_ISSUED_DL_MAG_DRAWINGS.txt
  3. A detailed examination of the MDL field map and the TOSCA model of this "5 MeV" dipole

Jay Benesch (JLab Tech note 15-017, September 9, 2015): media:TN-15-017_MDL_FieldMap.pdf media:Graphs_MDL.pdf media:Graphs_MDL.docx


New Hall Probe

  1. GMW DTM-151-PS Digital Teslameter, 20 Bit Resolution, RS-232 Interface, Panel Mtg media:G3_MAN_DTM-151-S.pdf
  2. GMW MPT-231-8s Miniature Hall Probe with thermal sensor, High Sensitivity 0.03T, 0.06T, 0.12T, & 0.3T, 8m shielded cable. 0.01% accuracy, resolution to 2 ppm, and a temperature stability of 10 ppm/°C.


PEPPo Results

Momentum Measurement:

Cryounit Gradient:

  • Upper limit of the electron beam energy at the CEBAF 2D injector spectrometer and its functionality

Jonathan Dumas, Joe Grames, and Eric Voutier Media:JLAB-TN-08-086.pdf

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