図目次

1. Scatter electron angular dependence of the virtual photon yield for the $^{12}$C target
2. Angular distribution of kaon in the $^{12}$C(e,e'K$^+$) $^{12}_{\Lambda }$B reaction.
3. Hypernuclear yield of $^{12}_{\Lambda }$B$_{gr}$ as a function of the beam energy assuming scattered electrons are measured at E$_{e}$ = 0.285 GeV.
4. Plan view of the high-resolution kaon spectrometer (HKS) and Enge spectrometer for the E01-011 experiment.
5. Enge tilt angle dependence of the expected rates. The beam current of 30$\mu$A and carbon target 100 mg/cm$^2$ are assumed. Figure of merit (FoM) is defined as $S/N^{1/2}$, where $S$ is the virtual photon flux and $N$ the sum of bremsstrahlung electrons and M$\phi$ller scattering electrons. To see the plot easily, the virtual photon flux is multiplied by 0.01 and FoM by arbitrary factor.
6. Expected Hall C setup of the HKS and Enge spectrometer. The installation can be compatible with the G0 setup.
7. Momentum correlation between kaon arm and electron arm for hyperons and hypernuclei production reaction.
8. Beam profile at each detector.
9. Momentum dependence of the solid angle of HKS.
10. Beam profile at collimator, Q1 entrance and exit, Q2 entrance and exit, and dipole entrance.
11. Two dimensional plot for angular acceptance of HKS for each momentum. Each ring corresponds to 0$^\circ$, 1$^\circ$ and so on.
12. The wire chamber resolution dependence of the HKS momentum resolution obtained by the GEANT simulation. The cases with and without multiple scattering effect were estimated.
13. The wire chamber resolution dependence of the angular resolution obtained by the GEANT simulation. Vertical and horizontal angular resolutions were separately estimated.
14. The electron scattering angle at the target for 4.5 degrees tilt and 4.5 cm vertical offset configuration of the Enge. The blue dots and black dots show electron distribution associated with virtual photons and M$\phi$ller scattering, respectively. Using RAYTRACE Monte Carlo simulation, the events which passed through the Enge spectrometer without hitting the pole or collimators were selected. The cyan points are the electrons associated with virtual photon which passed through the spectrometer and the red points for M$\phi$ller electrons.
15. Relative electrons rate dependence on the Enge tilt angle and Enge vertical offset for bremsstrahlung, M$\phi$ller scattering and virtual photons. For the electrons associated with the virtual photon which contributes to hypernuclear production. The hypernuclear production cross section is assumed as 100 nb/sr.
16. The electron scattering angle at the target for 7.75 degrees tilt.
17. Beam profile for each process at sieve slit (entrance of the Enge spectrometer). Densities of points are arbitrarily changed to see distribution clearly. Blue points are bremsstrahlung electrons, magenta the electrons associated with virtual photon production, green M$\phi$ller scattered electrons and red the electrons passed through the Enge spectrometer which associated with the virtual photon.
18. Side and front views of the Q1 magnet. Unit of size is millimeter.
19. Front and side views of the Q2 magnet. Unit of size is millimeter.
20. Picture of the completed Q1 magnet.
21. Picture of the completed Q2 magnet.
22. Top and side view of the D magnet. Unit of size is millimeter.
23. The calculated vertical field in the HKS-D magnet with TOSCA.
24. Picture of the completed D magnet.
25. Cross section of the Q1, Q2 and D magnets. Vacuum chambers are connected from the splitter magnet through Q1, Q2 and D magnets to the extension vacuum box.
26. A bird's-eye view of the target chamber to be installed in the Splitter magnet. The target located in the vacuum chamber could be inserted or removed without breaking vacuum.
27. The common base for the HKS Q1, Q2 and D magnets. Beam height can be adjusted with four hydraulic jacks (stroke $\pm$15 mm).
28. The picture of the HKS Q-Q-D system taken on July 7th, 2003 at Kobe (Mitsubishi Electric Co.).
29. The legs designed by Jlab engineer group. They will be bolted on the Hall C floor and support the common base for the HKS magnets. The height of the common base can be adjusted with the hydraulic jacks mounted on the legs.
30. The measured excitation curve (current vs. field gradient) for the Q1 magnet.
31. The measured excitation curve (current vs. field gradient) for the Q2 magnet.
32. The measured By fields along beam axis (Z) are compared with the TOSCA calculation results. The field shape is well reproduced the TOSCA result, and thus the magnets seems to be fabricated as designed.
33. The responses of the Hall probes rotated in the uniform field. Two Hall probes' (Bx, By) responses are naturally described by trigonometric functions of rotation angle ($\phi$). The remain probe (Bz) expect to have no dependence on $\phi$, but a few percent effect of the $2\phi$ component is observed. This is planar Hall effect. The stability of the magnetic field was monitored by NMR probe.
34. The excitation (BI) curve of the HKS D magnet. Red cross points are measured during current increasing, and blue points are done for decreasing current. Green points are expected values calculated with TOSCA.
35. The field mapping regions for the HKS D magnet. Downstream half will be completely mapped , but only fringe field region of the upstream half will be measured.
36. Schematic drawing of the counter test setup performed at KEK.
37. Picture of the aligned detectors at KEK-PS T1 beamline. From the upstream, the gas Cerenkov counter, Enge-hodoscopes, aerogel Cerenkov counters, water Cerenkov, HKS TOF counters can be seen.
38. The time of flight vs. number of photoelectrons measured with a water Cerenkov counter for for 1.2 GeV/$c$ protons, kaons and light particles ( $e^+,\mu ^+,\pi ^+$).
39. Layer configuration of the HKS drift chamber.
40. One layer board (u plane) of the HKS drift chamber. Anode wires are tilted with an angle of 30 degrees and their signals are amplified and discriminated with Nanometrics N277-L boards.
41. HKS drift chambers at the clean room. One completed chamber is now under conditioning. Other chambers are now under assembly.
42. Beam's eye view of HTF1X.
43. Beam's eye view and top view of HTF1Y.
44. The time difference spectrum between the HKS-TOF1X counter and the HKS-TOF2X counter after the pulse height (sluing) correction. The red line shows a fitted gaussian with a sigma of 77 ps.
45. Momentum dependence of the number of photoelectrons for Cerenkov counter for various refraction index (water: n = 1.33, Lucite: n = 1.48, PVT: n = 1.58). The number of photo electrons per path length in the radiator is calculated assuming the efficiency of the light correction and quantum efficiency of PMT are 90% and 27%, respectively.
46. A schematic drawing of the water Cerenkov counter.
47. Diffusion reflectance of various materials. ShikoLite-A is the acryl which we choose for the box material. The quantum efficiency of PMT is plotted in the same graph for reference.
48. The number of photoelectrons for 1.2 GeV/$c$ protons and kaons.
49. The kaon detection efficiency and contamination of protons in the kaon trigger for one layer of water Cerenkov counters. The numbers were calculated with the measured response to K$^+$ and proton, and beam distribution at the position of water Cerenkov estimated by the GEANT simulation.
50. Schematic of the aerogel Cerenkov counter's design.
51. Photoelectron yield of aerogel Cerenkov counter for pions at 1.2 GeV/$c$.
52. Measured pion veto inefficiency for one segment as a function of the threshold on each of the two PMTs.
53. Extrapolated pion veto inefficiency for three layers operated in one-out-of-three mode.
54. Picture of the aerogel Cerenkov counter's box.
55. Structure of the Enge honeycomb-cell structured drift chamber.
56. Picture of the Enge honeycomb-cell structured drift chamber located at Jlab EEL building. The chamber is placed to make the particle windows along gravity to use cosmic-ray for the test.
57. Efficiency curves for typical layers. Supplying HV $< -2100$V, the plane efficiency is nearly 100%.
58. Resolutions for various momentum.
59. A typical event display given by the tracking code developed for the Enge drift chamber. The tracks of $e^+ e^-$ pair from $\gamma$ conversion can be clearly seen in top view and side view.
60. Beam's eye view of Enge hodoscope.
61. Timing resolutions for Enge hodoscopes measured at KEK-PS. Gaussian fit gave $\sigma = 99$ ps, and thus time resolution of a single counter was obtained as 70 ps (rms).
62. The optical features for the tilted Enge spectrometer obtained by raytrace simulation. Top-left) scattering angle ($\theta _{e'}$ in degrees) distribution for the accepted events, top-right) scattering angle ($\theta _{e'}$) vs. the angle around the initial beam axis ($\phi _{e'}$ in degrees), bottom-left) correlation between the deviation from the central momentum ( $dp = p/p_0 - 1$, unit %) and $\theta _{e'}$, bottom-right) correlation between $dp$ and $\phi _{e'}$
63. The correlations between the deviation from the central momentum ($dp$) and observable quantities on the Enge focal plane. top-left) Momentum acceptance of Enge, top-right) $dp$ (%) vs. horizontal position (X$_f$, cm) , bottom-left) $dp$ vs. vertical position (Y$_f$, cm) bottom-right) $dp$ vs. horizontal angle (xpf, mrad).
64. The correlation between the horizontal position ($X_f$) and vertical position ($Y_f$) on the focal plane. Units are in centimeter.
65. Enge resolution for various position and angular resolution. The solid lines shows the resolution when $\sigma$X' and $\sigma$Y' are changed at the same time. Dashed line and dotted line shows the resolution when $\sigma$X' is fixed and only $\sigma$Y' varies.
66. The correlation between incident angle (in-plane $xpi$, off-plane $ypi$) and momentum for the electrons which passed through the Enge sieve slit.
67. The various plots for Enge sieve slit holes' images
68. The design of the HKS sieve slit. One hole is missing on purpose to identify easily up/down and left/right.
69. The various plots for HKS sieve slit holes' images. Left figures and right figures are identical, but different color patterns were assigned to columns and rows.
70. The flow chart for the HKS target angle calibration procedure.
71. The flow chart for the HKS sieve slit data fit.
72. The flow chart for the HKS momentum calibration.
73. HKS PID trigger.
74. BZ magnets. The deflected electrons by the Splitter magnet are bent back by the first BZ magnet (16.5 degrees) and the forward bremsstrahlung photons and the bent back electrons are merged by the second BZ magnet (8.35 degrees bent back) to be guided to the main dump.
75. Radiation budget.
76. Hall-C Beamline
77. E01-011 Schedule

図 1: Scatter electron angular dependence of the virtual photon yield for the $^{12}$C target

図 2: Angular distribution of kaon in the $^{12}$C(e,e'K$^+$) $^{12}_{\Lambda }$B reaction.

図 3: Hypernuclear yield of $^{12}_{\Lambda }$B$_{gr}$ as a function of the beam energy assuming scattered electrons are measured at E$_{e}$ = 0.285 GeV.

図 4: Plan view of the high-resolution kaon spectrometer (HKS) and Enge spectrometer for the E01-011 experiment.

図 5: Enge tilt angle dependence of the expected rates. The beam current of 30$\mu$A and carbon target 100 mg/cm$^2$ are assumed. Figure of merit (FoM) is defined as $S/N^{1/2}$, where $S$ is the virtual photon flux and $N$ the sum of bremsstrahlung electrons and M$\phi$ller scattering electrons. To see the plot easily, the virtual photon flux is multiplied by 0.01 and FoM by arbitrary factor.

図 6: Expected Hall C setup of the HKS and Enge spectrometer. The installation can be compatible with the G0 setup.

図 7: Momentum correlation between kaon arm and electron arm for hyperons and hypernuclei production reaction.

図 8: Beam profile at each detector.

図 9: Momentum dependence of the solid angle of HKS.

図 10: Beam profile at collimator, Q1 entrance and exit, Q2 entrance and exit, and dipole entrance.

図 11: Two dimensional plot for angular acceptance of HKS for each momentum. Each ring corresponds to 0$^\circ$, 1$^\circ$ and so on.

図 12: The wire chamber resolution dependence of the HKS momentum resolution obtained by the GEANT simulation. The cases with and without multiple scattering effect were estimated.

図 13: The wire chamber resolution dependence of the angular resolution obtained by the GEANT simulation. Vertical and horizontal angular resolutions were separately estimated.

図 14: The electron scattering angle at the target for 4.5 degrees tilt and 4.5 cm vertical offset configuration of the Enge. The blue dots and black dots show electron distribution associated with virtual photons and M$\phi$ller scattering, respectively. Using RAYTRACE Monte Carlo simulation, the events which passed through the Enge spectrometer without hitting the pole or collimators were selected. The cyan points are the electrons associated with virtual photon which passed through the spectrometer and the red points for M$\phi$ller electrons.

図 15: Relative electrons rate dependence on the Enge tilt angle and Enge vertical offset for bremsstrahlung, M$\phi$ller scattering and virtual photons. For the electrons associated with the virtual photon which contributes to hypernuclear production. The hypernuclear production cross section is assumed as 100 nb/sr.

図 16: The electron scattering angle at the target for 7.75 degrees tilt.

図 17: Beam profile for each process at sieve slit (entrance of the Enge spectrometer). Densities of points are arbitrarily changed to see distribution clearly. Blue points are bremsstrahlung electrons, magenta the electrons associated with virtual photon production, green M$\phi$ller scattered electrons and red the electrons passed through the Enge spectrometer which associated with the virtual photon.

図 18: Side and front views of the Q1 magnet. Unit of size is millimeter.

図 19: Front and side views of the Q2 magnet. Unit of size is millimeter.

図 20: Picture of the completed Q1 magnet.

図 21: Picture of the completed Q2 magnet.

図 22: Top and side view of the D magnet. Unit of size is millimeter.

図 23: The calculated vertical field in the HKS-D magnet with TOSCA.

図 24: Picture of the completed D magnet.

図 25: Cross section of the Q1, Q2 and D magnets. Vacuum chambers are connected from the splitter magnet through Q1, Q2 and D magnets to the extension vacuum box.

図 26: A bird's-eye view of the target chamber to be installed in the Splitter magnet. The target located in the vacuum chamber could be inserted or removed without breaking vacuum.

図 27: The common base for the HKS Q1, Q2 and D magnets. Beam height can be adjusted with four hydraulic jacks (stroke $\pm$15 mm).

図 28: The picture of the HKS Q-Q-D system taken on July 7th, 2003 at Kobe (Mitsubishi Electric Co.).

図 29: The legs designed by Jlab engineer group. They will be bolted on the Hall C floor and support the common base for the HKS magnets. The height of the common base can be adjusted with the hydraulic jacks mounted on the legs.

図 30: The measured excitation curve (current vs. field gradient) for the Q1 magnet.

図 31: The measured excitation curve (current vs. field gradient) for the Q2 magnet.

図 32: The measured By fields along beam axis (Z) are compared with the TOSCA calculation results. The field shape is well reproduced the TOSCA result, and thus the magnets seems to be fabricated as designed.

図 33: The responses of the Hall probes rotated in the uniform field. Two Hall probes' (Bx, By) responses are naturally described by trigonometric functions of rotation angle ($\phi$). The remain probe (Bz) expect to have no dependence on $\phi$, but a few percent effect of the $2\phi$ component is observed. This is planar Hall effect. The stability of the magnetic field was monitored by NMR probe.

図 34: The excitation (BI) curve of the HKS D magnet. Red cross points are measured during current increasing, and blue points are done for decreasing current. Green points are expected values calculated with TOSCA.

図 35: The field mapping regions for the HKS D magnet. Downstream half will be completely mapped , but only fringe field region of the upstream half will be measured.

図 36: Schematic drawing of the counter test setup performed at KEK.

図 37: Picture of the aligned detectors at KEK-PS T1 beamline. From the upstream, the gas Cerenkov counter, Enge-hodoscopes, aerogel Cerenkov counters, water Cerenkov, HKS TOF counters can be seen.

図 38: The time of flight vs. number of photoelectrons measured with a water Cerenkov counter for for 1.2 GeV/$c$ protons, kaons and light particles ( $e^+,\mu ^+,\pi ^+$).

図 39: Layer configuration of the HKS drift chamber.

図 40: One layer board (u plane) of the HKS drift chamber. Anode wires are tilted with an angle of 30 degrees and their signals are amplified and discriminated with Nanometrics N277-L boards.

図 41: HKS drift chambers at the clean room. One completed chamber is now under conditioning. Other chambers are now under assembly.

図 42: Beam's eye view of HTF1X.

図 43: Beam's eye view and top view of HTF1Y.

図 44: The time difference spectrum between the HKS-TOF1X counter and the HKS-TOF2X counter after the pulse height (sluing) correction. The red line shows a fitted gaussian with a sigma of 77 ps.

図 45: Momentum dependence of the number of photoelectrons for Cerenkov counter for various refraction index (water: n = 1.33, Lucite: n = 1.48, PVT: n = 1.58). The number of photo electrons per path length in the radiator is calculated assuming the efficiency of the light correction and quantum efficiency of PMT are 90% and 27%, respectively.

図 46: A schematic drawing of the water Cerenkov counter.

図 47: Diffusion reflectance of various materials. ShikoLite-A is the acryl which we choose for the box material. The quantum efficiency of PMT is plotted in the same graph for reference.

図 48: The number of photoelectrons for 1.2 GeV/$c$ protons and kaons.

図 49: The kaon detection efficiency and contamination of protons in the kaon trigger for one layer of water Cerenkov counters. The numbers were calculated with the measured response to K$^+$ and proton, and beam distribution at the position of water Cerenkov estimated by the GEANT simulation.

図 50: Schematic of the aerogel Cerenkov counter's design.

図 51: Photoelectron yield of aerogel Cerenkov counter for pions at 1.2 GeV/$c$.

図 52: Measured pion veto inefficiency for one segment as a function of the threshold on each of the two PMTs.

図 53: Extrapolated pion veto inefficiency for three layers operated in one-out-of-three mode.

図 54: Picture of the aerogel Cerenkov counter's box.

図 55: Structure of the Enge honeycomb-cell structured drift chamber.

図 56: Picture of the Enge honeycomb-cell structured drift chamber located at Jlab EEL building. The chamber is placed to make the particle windows along gravity to use cosmic-ray for the test.

図 57: Efficiency curves for typical layers. Supplying HV $< -2100$V, the plane efficiency is nearly 100%.

図 58: Resolutions for various momentum.

図 59: A typical event display given by the tracking code developed for the Enge drift chamber. The tracks of $e^+ e^-$ pair from $\gamma$ conversion can be clearly seen in top view and side view.

図 60: Beam's eye view of Enge hodoscope.

図 61: Timing resolutions for Enge hodoscopes measured at KEK-PS. Gaussian fit gave $\sigma = 99$ ps, and thus time resolution of a single counter was obtained as 70 ps (rms).

図 62: The optical features for the tilted Enge spectrometer obtained by raytrace simulation. Top-left) scattering angle ($\theta _{e'}$ in degrees) distribution for the accepted events, top-right) scattering angle ($\theta _{e'}$) vs. the angle around the initial beam axis ($\phi _{e'}$ in degrees), bottom-left) correlation between the deviation from the central momentum ( $dp = p/p_0 - 1$, unit %) and $\theta _{e'}$, bottom-right) correlation between $dp$ and $\phi _{e'}$

図 63: The correlations between the deviation from the central momentum ($dp$) and observable quantities on the Enge focal plane. top-left) Momentum acceptance of Enge, top-right) $dp$ (%) vs. horizontal position (X$_f$, cm) , bottom-left) $dp$ vs. vertical position (Y$_f$, cm) bottom-right) $dp$ vs. horizontal angle (xpf, mrad).

図 64: The correlation between the horizontal position ($X_f$) and vertical position ($Y_f$) on the focal plane. Units are in centimeter.

図 65: Enge resolution for various position and angular resolution. The solid lines shows the resolution when $\sigma$X' and $\sigma$Y' are changed at the same time. Dashed line and dotted line shows the resolution when $\sigma$X' is fixed and only $\sigma$Y' varies.

図 66: The correlation between incident angle (in-plane $xpi$, off-plane $ypi$) and momentum for the electrons which passed through the Enge sieve slit.

図 67: The various plots for Enge sieve slit holes' images

図 68: The design of the HKS sieve slit. One hole is missing on purpose to identify easily up/down and left/right.

図 69: The various plots for HKS sieve slit holes' images. Left figures and right figures are identical, but different color patterns were assigned to columns and rows.

図 70: The flow chart for the HKS target angle calibration procedure.

図 71: The flow chart for the HKS sieve slit data fit.

図 72: The flow chart for the HKS momentum calibration.

図 73: HKS PID trigger.

図 74: BZ magnets. The deflected electrons by the Splitter magnet are bent back by the first BZ magnet (16.5 degrees) and the forward bremsstrahlung photons and the bent back electrons are merged by the second BZ magnet (8.35 degrees bent back) to be guided to the main dump.

図 75: Radiation budget.

図 76: Hall-C Beamline

図 77: E01-011 Schedule