Tamar Thesis EperimentalSetupChapt - Revision history

Didbtama: /* Notes */

2012-12-10T06:47:00Z

Notes

Foretony: /* Polarized Target Materials */

2012-09-14T17:53:23Z

Polarized Target Materials

Foretony: /* Introduction */

2012-05-11T19:27:24Z

Introduction

Foretony: /* Introduction */

2012-05-11T19:25:53Z

Introduction

Didbtama: /* Introduction */

2012-05-04T17:29:49Z

Introduction

Didbtama: /* Introduction */

2012-05-04T17:24:58Z

Introduction

Didbtama: /* Polarized Target Materials */

2012-05-04T17:18:12Z

Polarized Target Materials

Didbtama: /* The Target Chamber */

2012-05-02T22:41:04Z

The Target Chamber

Didbtama: /* Polarized Target Materials */

2012-05-02T22:40:45Z

Polarized Target Materials

Didbtama: /* Introduction */

2012-05-02T22:39:36Z

Introduction

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 ==Polarized Target Materials==
 A polarized solid target's limited resistance to radiation damage is one of the remaining challenges for using polarized targets in scattering experiments.  At present, solid ammonia and lithium deuteride are the target materials with the highest resistance to radiation damage<ref name="Baum1996"> Baum G, et al. A proposal for a Common Muon and Proton Apparatus for Structure and spectroscopy, CERN/SPSLC/96-14(1996).</ref>. . For EG1b experiment, ammonia targets were selected because of their ability to produce high polarization and be resistant to high radiation dose caused by the incident electron beam. Another advantage of ammonia target is a high ratio of free nucleons  (~3/18), approximately 16.7 % for <math>^{15}NH_3</math> and 28.6% for <math>^{15}ND_3</math>. One disadvantage of choosing ammonia is the polarization background caused by <math>^{15}N</math>(spin - 1/2), or <math>^{14}N</math>(spin - 1), which was accounted for by taking data using a solid <math>^{15}N</math> target <ref name="Keith2003"> Keith, C. D., et al. (2003). A Polarized target for the CLAS detector. ''NIM, A''(501), 327-339. 327-339.</ref> <ref name="Chen2006">Chen, S. (2006). ''First Measurement of Deeply Virtual Compton Scattering with a Polarized Proton Target''.  Doctoral dissertation. Florida State University, Tallahasee, FL. </ref>. The main target materials used for the EG1b experiment were frozen ammonia, <math>^{15}NH_3</math>, for the polarized protons and deuterated ammonia, <math>^{15}ND_3</math> for the polarized deuterons.  In addition to <math>^{15}ND_3</math> and <math>^{15}NH_3</math> targets, <math>C_{12}</math>, liquid <math>He^4</math> and solid <math>N_{15}</math> were used to estimate the dilution of the data by background noise which can be attributed to the interaction of the incident electron with the Nitrogen or Helium nucleons present in the target cell.  This estimate is referred to as a dilution factor <ref name="Keith2003"> Keith, C. D., et al. (2003). A Polarized target for the CLAS detector. ''NIM, A''(501), 327-339. 327-339.</ref> .<br>
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 ==Introduction==
-Polarized targets and polarized beams are recently acquired research tools being used to investigate the spin structure of the nucleon. The inclusive scattering experiments using the polarized targets and beams give availability to measure observables with utilizing spin degrees of freedom, like the spin structure of the nucleon, the electromagnetic structure of the nucleon in its ground state and etc. <ref name="Averett1999"> T.D. Averett et al. (1999). "A solid polarized target for high-luminosity experiments". ''Nucl. Instr. Meth'' '''A 427/3''', 440-454</ref> The technology producing targets containing polarized nucleons have been developed over the past 50 years. For the experiments using electrons as probes, due to the small cross section of the electromagnetic interactions, one of the requirements for polarized targets are a large thickness and resistance to the electron beam intensity without significant radiation damage. The solid targets for the EG1B experiment were polarized via the Dynamic Nuclear Polarization (DNP) method<ref name="CrabbMeyer1997"> Crabb, D.G., Meyer, W.(1997). "Solid Polarized Targets for Nuclear and Particle Physics Experiments". ''Annu. Rev. Nucl. Part. Sci'' '''47''', 67-109</ref>.<br>
+Polarized targets and polarized beams are recently acquired research tools being used to investigate the spin structure of the nucleon. Inclusive scattering experiments using polarized targets and beams facilitate measurements of observables exhibiting spin degrees of freedom, like the spin structure of the nucleon, the electromagnetic structure of the nucleon in its ground state, etc. <ref name="Averett1999"> T.D. Averett et al. (1999). "A solid polarized target for high-luminosity experiments". ''Nucl. Instr. Meth'' '''A 427/3''', 440-454</ref> The technology producing targets containing polarized nucleons have been developed over the past 50 years. For the experiments using electrons as probes, due to the small cross section of the electromagnetic interactions, one of the requirements for polarized targets are a large thickness and resistance to the electron beam intensity without significant radiation damage. The solid targets for the EG1B experiment were polarized via the Dynamic Nuclear Polarization (DNP) method<ref name="CrabbMeyer1997"> Crabb, D.G., Meyer, W.(1997). "Solid Polarized Targets for Nuclear and Particle Physics Experiments". ''Annu. Rev. Nucl. Part. Sci'' '''47''', 67-109</ref>.<br>
 EG1b polarized target system consists the following main components: the superconducting Helmholtz coils to reach 5 T magnetic field, the evaporation refrigerator for target cooling, the microwaves to induce spin flip in the target, NMR system measuring the target polarization and the housing for the solid target <ref name="Averett1999"> T.D. Averett et al. (1999). "A solid polarized target for high-luminosity experiments". ''Nucl. Instr. Meth'' '''A 427/3''', 440-454</ref>.  <br>
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 ==Introduction==
-Polarized targets and polarized beams are recently acquired research tools being used to investigate the spin structure in the nucleon. The inclusive scattering experiments using the polarized targets and beams give availability to measure observables with utilizing spin degrees of freedom, like the spin structure of the nucleon, the electromagnetic structure of the nucleon in its ground state and etc. <ref name="Averett1999"> T.D. Averett et al. (1999). "A solid polarized target for high-luminosity experiments". ''Nucl. Instr. Meth'' '''A 427/3''', 440-454</ref> The technology producing targets containing polarized nucleons have been developed over the past 50 years. For the experiments using electrons as probes, due to the small cross section of the electromagnetic interactions, one of the requirements for polarized targets are a large thickness and resistance to the electron beam intensity without significant radiation damage. The solid targets for the EG1B experiment were polarized via the Dynamic Nuclear Polarization (DNP) method<ref name="CrabbMeyer1997"> Crabb, D.G., Meyer, W.(1997). "Solid Polarized Targets for Nuclear and Particle Physics Experiments". ''Annu. Rev. Nucl. Part. Sci'' '''47''', 67-109</ref>.<br>
+Polarized targets and polarized beams are recently acquired research tools being used to investigate the spin structure of the nucleon. The inclusive scattering experiments using the polarized targets and beams give availability to measure observables with utilizing spin degrees of freedom, like the spin structure of the nucleon, the electromagnetic structure of the nucleon in its ground state and etc. <ref name="Averett1999"> T.D. Averett et al. (1999). "A solid polarized target for high-luminosity experiments". ''Nucl. Instr. Meth'' '''A 427/3''', 440-454</ref> The technology producing targets containing polarized nucleons have been developed over the past 50 years. For the experiments using electrons as probes, due to the small cross section of the electromagnetic interactions, one of the requirements for polarized targets are a large thickness and resistance to the electron beam intensity without significant radiation damage. The solid targets for the EG1B experiment were polarized via the Dynamic Nuclear Polarization (DNP) method<ref name="CrabbMeyer1997"> Crabb, D.G., Meyer, W.(1997). "Solid Polarized Targets for Nuclear and Particle Physics Experiments". ''Annu. Rev. Nucl. Part. Sci'' '''47''', 67-109</ref>.<br>
 EG1b polarized target system consists the following main components: the superconducting Helmholtz coils to reach 5 T magnetic field, the evaporation refrigerator for target cooling, the microwaves to induce spin flip in the target, NMR system measuring the target polarization and the housing for the solid target <ref name="Averett1999"> T.D. Averett et al. (1999). "A solid polarized target for high-luminosity experiments". ''Nucl. Instr. Meth'' '''A 427/3''', 440-454</ref>.  <br>
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 ==Introduction==
-Polarized targets and polarized beams are recently acquired research tools being used to investigate the spin structure in the nucleon.
+Polarized targets and polarized beams are recently acquired research tools being used to investigate the spin structure in the nucleon. The inclusive scattering experiments using the polarized targets and beams give availability to measure observables with utilizing spin degrees of freedom, like the spin structure of the nucleon, the electromagnetic structure of the nucleon in its ground state and etc. <ref name="Averett1999"> T.D. Averett et al. (1999). "A solid polarized target for high-luminosity experiments". ''Nucl. Instr. Meth'' '''A 427/3''', 440-454</ref> The technology producing targets containing polarized nucleons have been developed over the past 50 years. For the experiments using electrons as probes, due to the small cross section of the electromagnetic interactions, one of the requirements for polarized targets are a large thickness and resistance to the electron beam intensity without significant radiation damage. The solid targets for the EG1B experiment were polarized via the Dynamic Nuclear Polarization (DNP) method<ref name="CrabbMeyer1997"> Crabb, D.G., Meyer, W.(1997). "Solid Polarized Targets for Nuclear and Particle Physics Experiments". ''Annu. Rev. Nucl. Part. Sci'' '''47''', 67-109</ref>.<br>
 EG1b polarized target system consists the following main components: the superconducting Helmholtz coils to reach 5 T magnetic field, the evaporation refrigerator for target cooling, the microwaves to induce spin flip in the target, NMR system measuring the target polarization and the housing for the solid target <ref name="Averett1999"> T.D. Averett et al. (1999). "A solid polarized target for high-luminosity experiments". ''Nucl. Instr. Meth'' '''A 427/3''', 440-454</ref>.  <br>
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   Rework this paragraph
-inclusive scattering experiments using the polarized targets and beams give availability to measure observables with utilizing spin degrees of freedom, like the spin structure of the nucleon, the electromagnetic structure of the nucleon in its ground state and etc. <ref name="Averett1999"> T.D. Averett et al. (1999). "A solid polarized target for high-luminosity experiments". ''Nucl. Instr. Meth'' '''A 427/3''', 440-454</ref> The technology producing targets containing polarized nucleons have been developed over the past 50 years. For the experiments using electrons as probes, due to the small cross section of the electromagnetic interactions, one of the requirements for polarized targets are a large thickness and resistance to the electron beam intensity without significant radiation damage. The solid targets for the EG1B experiment were polarized via the Dynamic Nuclear Polarization (DNP) method.<br>
+inclusive scattering experiments using the polarized targets and beams give availability to measure observables with utilizing spin degrees of freedom, like the spin structure of the nucleon, the electromagnetic structure of the nucleon in its ground state and etc. <ref name="Averett1999"> T.D. Averett et al. (1999). "A solid polarized target for high-luminosity experiments". ''Nucl. Instr. Meth'' '''A 427/3''', 440-454</ref> The technology producing targets containing polarized nucleons have been developed over the past 50 years. For the experiments using electrons as probes, due to the small cross section of the electromagnetic interactions, one of the requirements for polarized targets are a large thickness and resistance to the electron beam intensity without significant radiation damage. The solid targets for the EG1B experiment were polarized via the Dynamic Nuclear Polarization (DNP) method<ref name="CrabbMeyer1997"> Crabb, D.G., Meyer, W.(1997). "Solid Polarized Targets for Nuclear and Particle Physics Experiments". ''Annu. Rev. Nucl. Part. Sci'' '''47''', 67-109</ref>.<br>
 EG1b polarized target system consists the following main components: the superconducting Helmholtz coils to reach 5 T magnetic field, the evaporation refrigerator for target cooling, the microwaves to induce spin flip in the target, NMR system measuring the target polarization and the housing for the solid target <ref name="Averett1999"> T.D. Averett et al. (1999). "A solid polarized target for high-luminosity experiments". ''Nucl. Instr. Meth'' '''A 427/3''', 440-454</ref>.  <br>
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 |}<br>
 During the experiment, two of the target cells were filled with <math>NH3</math> and <math>ND3</math>, a third cell with a <math>2.3 mm</math> thick graphite disk, and the last cell was left empty. The <math>NH3</math> and <math>ND3</math> targets were used for physics measurements, while the carbon and the empty cells for background measurements. The desired target cell can be placed along the beam axis using a stepping motor. The NMR coils were wrapped around the outside surface of the cells. The coils, a <math>0.15 mm</math> in diameter <math>CuNi</math> tubing, were shaped rectangularly. Only one loop of NMR coils was used for the <math>NH3</math> target, while the <math>ND3</math> target required four loops to measure the polarization. Temperature sensors were located at several places of the target chamber and heater coils were attached below each target cell for annealing.
 ==Polarized Target Materials==

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 [[File:EG1PolarizedTarget.png|400px|thumb|EG1b Polarized Target System.]]
 |}<br>
 ===Target Magnet===