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From Desire to Data: How JLab’s Experimental Program Evolved Part 2: The Painstaking Transition to Concrete Plans, Mid-1980s to 1990

Abstract

This is the second in a three-part article describing the development of the Thomas Jefferson National Accelerator Facility’s experimental program, from the first dreams of incisive electromagnetic probes into the structure of the nucleus through the era in which equipment was designed and constructed and a program crafted so that the long-desired experiments could begin. These developments unfolded against the backdrop of the rise of the more bureaucratic New Big Science and the intellectual tumult that grew from increasing understanding and interest in quark-level physics. Part 2, presented here, focuses on the period from 1986 to 1990. During this period of revolutionary change, laboratory personnel, potential users, and DOE officials labored to proceed from the 1986 laboratory design report, which included detailed accelerator plans and very preliminary experimental equipment sketches, to an approved 1990 experimental equipment conceptual design report, which provided designs complete enough for the onset of experimental equipment construction.

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Fig. 1

Credit: Thomas Jefferson National Accelerator Facility

Fig. 2

Credit: Thomas Jefferson National Accelerator Facility

Fig. 3

Credit: Thomas Jefferson National Accelerator Facility

Notes

  1. At the time, the laboratory was called the Continuous Electron Beam Accelerator Facility (CEBAF). As of 2018, the accelerator facility is still known by that name, but the laboratory is the Thomas Jefferson National Accelerator Facility or JLab. For simplicity and clarity, the laboratory is called JLab throughout this article.

References

  1. Catherine Westfall, “From Desire to Data: How JLab’s Experimental Program Evolved,” pt. 1, “From Vision to Dream Equipment, the Mid-1980,” Physics in Perspective 18 (2016), 301–50.

  2. CEBAF, “CEBAF Design Report,” May 1986, Jefferson Laboratory Library Archives, Newport New, VA (hereafter JLL).

  3. For more on the rise of the New Big Science, see Robert P. Crease and Catherine Westfall, “The New Big Science,” Physics Today 69 (2016), 30–36.

  4. CEBAF, “Experimental Equipment Conceptual Design Report,” CEBAF R-90-001, JLL.

  5. During the fifteen years of operation of the accelerator, which operated first at 4 GeV and later at 6 GeV, nearly two hundred experiments were conducted. In 2008 a major upgrade of the facility was initiated, which was completed in September 2017. The upgrade doubled the beam energy, added a fourth experimental hall, and provided a new suite of major experimental equipment.

  6. Hermann A. Grunder, “New Performance-Based Contract,” SURA Review of CEBAF, November 29–December 1995, JLL. For more on the development and funding of the laboratory as a whole, see Catherine Westfall, “A Tale of Two More Laboratories: Readying for Research at Fermilab and Jefferson Laboratory,” Historical Studies in the Physical and Biological Sciences 32 (2002), 369–407.

  7. See Catherine Westfall, “Introduction to the Special Issue: Surviving the Squeeze: National Laboratories in the 1970s and 1980s,” Historical Studies in the Natural Sciences 38 (2008), 475–78.

  8. The estimate for the cost of experimental equipment provided in the May 1986 CEBAF design report (ref. 2) was $39 million, but this obviously underestimated amount is given as $40 million in subsequent informal documents.

  9. For more on the history of RHIC, see Robert Crease, “Recombinant Science: The Birth of the Relativistic Heavy Ion Collider,” in Historical Studies in the Natural Sciences 38 (2008), 535–68.

  10. Department of Energy, “DOE Review Committee Report, October 6–8, 1986,” JLL, 9.

  11. Westfall, “From Desire to Data” (ref. 1), 313.

  12. T. de Forest and J. D. Walecka, “Electron Scattering and Nuclear Structure,” Advanced in Physics 15 (1966), 1–109; T. W. Donnelly and J. D. Walecka, “Electron Scattering and Nuclear Structure,” Annual Review of Nuclear Science 25 (1975), 329–405.

  13. DOE, “Review Committee Report, 1986” (ref. 10), 14.

  14. J. Dirk Walecka, memo to the CEBAF users group, October 3, 1986, JLL.

  15. Quotes, respectively, from J. Dirk Walecka, interview with Catherine Westfall, September 25, 1990, JLL and John Schiffer, letter to J. Dirk Walecka, October 31, 1986, Schiffer files, Argonne National Laboratory, Argonne, Illinois, 60439 (hereafter ANL).

  16. The design was from a 1971 proposal by H.-J. Besch and U. Trinks to build a toroidal detector for the DORIS e + e ring at DESY. Larry Cardman, personal communication, July 11, 2016.

  17. For a discussion of the 1981 Blue Book and related planning, see Westfall, “From Desire to Data” (ref. 1), 311–13.

  18. J. Dirk Walecka, interview with Catherine Westfall, February 16, 1998, JLL.

  19. J. Dirk Walecka, letter to Hermann Grunder, December 15, 1986, JLL.

  20. Quotes, respectively, from Larry Cardman, personal communication, March 29, 1996, and Bernhard Mecking, interview with Catherine Westfall, September 10, 1997.

  21. John Domingo, interview with Catherine Westfall, November 9, 1998, JLL.

  22. Mecking, interview with Westfall (ref. 20).

  23. Luminosity describes the ratio between the number of events per second and the cross section for the reaction(s) of interest. It can be limited by the beam intensity available, by the target thickness, by the beam deliverable to the target without damage, or by the rate limitations of the detector, which are often imposed by its ability to separate and identify events of interest from backgrounds.

  24. The higher luminosity mentioned here is connected to the luminosity that could be achieved with CLAS; this luminosity is higher than for tagged photons (with CLAS) but lower than what can be achieved with the magnetic spectrometers. The key advantage of CLAS for these experiments is that it can look at the full range of angles for the reaction products and a large range of electron scattering angles simultaneously. Text quotes: Lawrence Cardman and J. Dirk Walecka, interview with Catherine Westfall, August 8, 2013, JLL.

  25. Quotes from Mecking, interview with Westfall (ref. 20); Larry Cardman, personal communication, April 8, 1999.

  26. Mecking, interview with Westfall (ref. 20).

  27. Quotes, respectively, from Program Advisory Committee, “Report of the Program Advisory Committee for CEBAF,” March, 1987, JLL, 3–4, and DOE, “Review Committee Report, 1986” (ref. 10), 9.

  28. J. Dirk Walecka, memo to members of the CEBAF users group, March 23, 1987, JLL, and J. Dirk Walecka, personal communication, February 21, 2017.

  29. Quotes from Larry Cardman, personal communication, June 26, 2017; John Schiffer, personal communication to Larry Cardman, May 1, 2017.

  30. This is possible because, once one of the nucleons has been replaced with a hyperon, it is possible to avoid the exclusion principle since the hyperon is not identical to the nucleons in the nucleus under study in the experiment. Text reference: J. Dirk Walecka, memo to the CEBAF users group, March 23, 1987, JLL.

  31. Grunder completed the end station work with the help of a task force he chaired. The other members were P. Brindza, G. Doddy, O. Mattherny, B. Mecking. J. O’Meara, J. Mougey, G. Stapleton, R. Whitney, and R. York. J. Dirk Walecka, “Scientific Director,” Semi-Annual Review, May 5–6, 1987, JLL. Text reference: Dirk Walecka, memo to the CEBAF Users Group, March 23, 1987, JLL.

  32. J. Dirk Walecka, “Scientific Program and Equipment Plans,” Semi-Annual Review, November 17–19, 1987, JLL.

  33. This version of the detector is a lower field variation of the Octopus magnet proposed in 1971 by H.-J. Besch and U. Trinks for the e + e storage ring DORIS at DESY. See H.-J. Besch and U. Trinks, “A Proposal for a Magnetic Detector at the DESY Storage Ring,” Bonn University Internal Report PIB 1-150 (1971) (in German), and H.-J. Besch and U. Trinks, “Proposal to Build the Octopus Magnet for the DESY Storage Ring,” Bonn University Internal Report PIB 1-180 (1972) (in German). The author thanks Larry Cardman for these documents.

  34. Research Program at CEBAF (III), “Report of the 1987 Summer Study Group,” June 1–August 28, 1987, JLL.

  35. In addition to Peoples, the TAP included: Dr. D. A. Bryman from TRIUMF; Dr. John Cameron from the University of Alberta; David Cassel from Cornell University; Martin Cooper from Los Alamos National Laboratory; Paul Debevec, from the University of Illinois at Urbana-Champagne; Jay Marx from Lawrence Berkeley Laboratory, Clyde Taylor from Lawrence Berkeley Laboratory; Albert Ulbricht from Oak Ridge National Laboratory; Karl VanBibber from Lawrence Livermore National Laboratory.

  36. Quotes, respectively, from Bernhard Mecking, videotaped speech at the Domingo Day Symposium, January 9, 1997, and Mecking, interview with Westfall (ref. 20). The author thanks Bernhard Mecking for the videotaped speech.

  37. J. Dirk Walecka, email to John Schiffer, September 25, 1987, Schiffer Files, ANL; J. Dirk Walecka, memo to the CEBAF Users Group, November 10, 1987, JLL.

  38. John Peoples for the Technical Advisory Committee, letter to J. Dirk Walecka, October 8, 1987, JLL.

  39. Bernhard Mecking, interview with Catherine Westfall, March 29, 1996, JLL.

  40. Program Advisory Committee, “Report of the CEBAF Program Advisory Committee,” October 29, 1987, JLL.

  41. Quotes from Walecka, interview with Westfall (ref. 18); “Proceedings CEBAF/SURA 1988 Workshop,” June 20–24, 1988, JLL, 24.

  42. Program Advisory Committee, “CEFAB Report” (ref. 40), 1. “Out-of-plane” refers to the measurement of one of the reaction particles out of the scattering plane (the plane defined by the incident and scattered electron trajectories). Such measurements provide new information on the nucleus and the reaction being studied through their sensitivity to elements of the reaction that are not measurable in the scattering plane.

  43. Ibid., 2–3.

  44. Ibid., “CEFAB Report” (ref. 40), 2, 4.

  45. Ibid., “CEFAB Report” (ref. 40), 5–7.

  46. Ibid.

  47. “Report of the SURA Review Committee Meeting,” December 9, 1989, Schiffer files, ANL.

  48. Quotes from J. Dirk Walecka, memo to the CEBAF users group, November 10, 1987; Walecka, interview with Westfall (ref. 15).

  49. Hermann Grunder, “Director’s Overview,” DOE/CEBAF Monthly Progress Meeting, January 6, 1988, JLL.

  50. Quotes from L. Edward Temple, “Report of the DOE Review Committee on the Third Semi-Annual on the Continuous Electron Beam Accelerator Facility (CEBAF),” November 17–19, 1987; Hermann Grunder, interview with Catherine Westfall, February 12, 1997, JLL, and Domingo, interview with Westfall (ref. 21).

  51. Quotes, respectively, from L. Edward Temple, “Report of the DOE Review Committee on the Third Semi-Annual Review of the Continuous Electron Accelerator Facility,” November 17–19, 1987, JLL; “Report of the SURA Review Committee for CEBAF,” December 9, 1987, Schiffer files, ANL; and J. Dirk Walecka, memo to the CEBAF users group, November 10, 1987, JLL; John Schiffer, interview with Catherine Westfall, May 26, 1998, JLL.

  52. Domingo, interview with Westfall (ref. 21).

  53. CEBAF, “Experimental Equipment Conceptual Design Report,” CEBAF R-90-001, JLL, A4-3.

  54. Quotes from Walecka, interview with Westfall, (ref. 18); John Domingo, interview with Catherine Westfall, July 8, 1996, JLL.

  55. Walecka, interview with Westfall, (ref. 18).

  56. Quotes, respectively, from Domingo, interview with Westfall (ref. 54), and Walecka, interview with Westfall (ref. 18).

  57. “Report of the Technical Advisory Panel on the High Resolution Spectrometers,” April 28–29, 1988, JLL, 2, 11–12. In addition to Kowalski and Brown, the HRS2 TAP included: H. DeVries, from NIKHEF; P. Debenham, from NBS; H. Desportes, from CEN Saclay; R. A. Eisenstein, from the University of Illinois; J. Nolen, from Michigan State University; P. Reardon, from Brookhaven National Laboratory; R. Smith from Fermilab; T. Taylor from CERN; and A. Thiessen, from LAMPF.

  58. “Report of the Technical Advisory Panel on the High Resolution Spectrometers,” April 28–29, 1988, JLL, 10, 12.

  59. Quotes, respectively, from “Report of the Technical Advisory Panel on the High Resolution Spectrometers,” April 28–29, 1988, JLL, 10, 12.

  60. Quotes respectively, from Bernhard Mecking, personal communication, April 3, 2017, and Domingo, interview with Westfall (ref. 54).

  61. “Conceptual Design Report Civil Construction for End Stations CEBAF,” May 1988, JLL, 4-20, 4-21, 5.1.

  62. Quotes, respectively, from “Highlights of 4/11/88 Discussion at O’Hare” and Proceedings CEBAF/SURA 1988 Summer Workshop,” June 20–24, 1988, JLL, I. The author thanks Larry Cardman for the former document. See also: “CEBAF Semi-Annual Review,” July 19–21, 1988, JLL; J. Dirk Walecka, memo to the CEBAF users group, April 11, 1988, JLL.

  63. Quotes from Roger Carlini, “End Station C Preconceptual Design Report Outline,” Semi-Annual DOE Review, July 19–21, 1988, JLL; Roger Carlini, interview with Catherine Westfall, September 10, 1997, JLL.

  64. For hypernuclear experiments it is essential that the path length in the spectrometer be as short as possible as the reaction particles decay, and in experiments such as deuteron photodisintegration, which probe the very short distance structure of this key nucleus, the reaction produces particles with momenta higher than the momentum of the beam. Text quote: Carlini, interview with Westfall (ref. 63).

  65. Quotes from Domingo, interview with Westfall (ref. 54).

  66. John Schiffer, email to PAC members, June 20, 1988, and appended email correspondence, Schiffer files, ANL.

  67. “Report of the DOE Review Committee on the Fourth Semi-Annual Review of the Continuous Electron Beam Accelerator Facility, CEBAF,” July 19–21, 1988, JLL, 6–7.

  68. Quotes from John Schiffer, email to PAC members, August 4, 1988, Schiffer files, ANL; J. Dirk Walecka, memo to CEBAF PAC Members, August 3, 1988, JLL.

  69. Harold Jackson, “CEBAF Users Group,” National Advisory Board, September 22–23, 1988, JLL.

  70. Roger Carlini, “CEBAF End Station C (User Implemented Spectrometers),” National Advisory Board, September 22–23, 1988, JLL.

  71. Larry Cardman, personal communication, March 29, 1996.

  72. Carlini, “CEBAF End Station C” (ref. 70).

  73. Carlini, “CEBAF End Station C” (ref. 70), and Don Geesaman, “Summary Argonne-Illinois Hall C Meeting,” email to John Schiffer and appended documents, Schiffer files, ANL.

  74. Mecking, interview with Westfall (ref. 39).

  75. Quotes, respectively, from Carlini, interview with Westfall (ref. 63), and Mecking, interview with Westfall (ref. 20); John Schiffer, memo to PAC3, November 22, 1988, and appended documents, Schiffer files, ANL.

  76. Quotes from J. Dirk Walecka, memo to CEBAF Staff, October 31, 1988, JLL; “Report of the SURA Review Committee for CEBAF,” December 9, 1987, JLL.

  77. J. Dirk Walecka, memo to CEBAF Staff, October 31, 1988, JLL.

  78. “The Experimental Equipment Preliminary Conceptual Design Report,” December 1988, E3, JLL.

  79. The Møller electrons come from elastic scattering of the incident electron beam from the electrons in the target (that is, electron-electron scattering). They are copious and can overwhelm the detectors trying to see the nucleon or nucleus reaction products, so keeping them out of the detectors by the addition of shielding in the forward direction greatly improves the luminosity capability of the detector system.

  80. In addition to Barnes, the TAP included Douglas Bryman from TRIUMF, John Cameron from Indiana University, David Cassel from Cornell, Martin Cooper from Los Alamos National Laboratory, Paul Debevec from the University of Illinois, Gail Hanson from SLAC, Daniel Marlow from Princeton University, Jay Marx from Lawrence Berkeley Laboratory, John Purcel, from Advanced Cryomagnetics in San Diego, and Clyde Taylor from Lawrence Berkeley Laboratory.

  81. “Report of the Technical Advisory Panel for the Large Acceptance Spectrometer,” January 20, 1989, JLL.

  82. Elastic scattering measurements are so called because the sum of the kinetic energy of the incident electron and the nucleus is conserved, as the electron’s direction of propagation is modified, the struck nucleus recoils, and the struck nucleus remains in its ground state. Inelastic scattering measurements are so called because the sum of the kinetic energy of the incident electron and the nucleus is not conserved in the reaction: some of the energy is transferred from the scattering electron to the nucleus itself, leaving it in an excited state.

  83. Quotes from Mecking, interview with Westfall (ref. 20). Also: Bernhard Mecking, “Large Acceptance Spectrometer Overview,” Second Meeting of the Technical Advisory Panel for the Large Acceptance Spectrometer, November 17–19, 1998, JLL.

  84. Mecking, interview with Westfall (ref. 20).

  85. Quotes, respectively, from “Report of the Technical Advisory Panel for the Large Acceptance Spectrometer,” January, 1989, JLL, 1, 2.

  86. Quotes, respectively, from “Report of the Technical Advisory Panel for the Large Acceptance Spectrometer,” January, 1989, JLL, 3, 4.

  87. Bernhard Mecking and Robert McKeown, email to “Everybody Interested in the LAS,” November 24, 1988, JLL.

  88. Robert Eisenstein, email to John Schiffer, November 29, 1988; Peter Barnes, email to John Schiffer and J. Dirk Walecka, December 2, 1988, and appended documents, Schiffer files, ANL.

  89. CEBAF, “Preconceptual Design Report,” Continuous Electron Beam Accelerator Facility, December 1985, JLL, 157.

  90. CEBAF, “Preconceptual Design Report,” Continuous Electron Beam Accelerator Facility, December 1985 JLL, 157.

  91. In addition to Schiffer, Eisenstein, Peoples, Richter, and Samios, the committee included D. Allan Bromley from Yale, John C. Browne from Los Alamos National Laboratory, Art Kerman from MIT, and David Shirley from Lawrence Berkeley Laboratory.

  92. Quotes from “1988 SURA Review Committee for CEBAF,” December 7, 1988, JLL, 3; J. Dirk Walecka, memo to the CEBAF users group, January 5, 1989, JLL.

  93. “1988 SURA Review Committee for CEBAF,” December 7, 1988, JLL, 2.

  94. Ibid., 6.

  95. Ibid., 4.

  96. Ibid.

  97. Ibid., 3.

  98. J. Dirk Walecka, memo to the CEBAF users group, January 5, 1989, JLL; CEBAF, “Experimental Equipment Preliminary Conceptual Design Report,” December 1988, JLL.

  99. J. Dirk Walecka, memo to the CEBAF users group, January 5, 1989, JLL.

  100. Ibid.

  101. Ibid.

  102. Ibid.

  103. L. Edward Temple, “Report of the DOE Review Committee on the Fifth Semiannual Review of the Continuous Electron Beam Accelerator Facility,” CEBAF, January 17–19, 1989, JLL.

  104. Ibid.

  105. John Schiffer, email to Hermann Grunder and J. Dirk Walecka, March 30, 1989, Schiffer files, ANL.

  106. “Report of the CEBAF Program Advisory Committee,” March 28, 1989, JLL.

  107. Quotes from J. Dirk Walecka, email to John Schiffer, March 28, 1989, Schiffer files, ANL; John Schiffer, email to Hermann Grunder and J. Dirk Walecka, March 30, 1989, Schiffer files, ANL; J. Dirk Walecka, “Scientific Overview,” Semi-Annual Review, September 19–21, 1989, JLL.

  108. John Domingo, “Domingo’s Thoughts on Hall Collaborations,” January 4, 1989, JLL.

  109. Ibid.

  110. DOE/NSF Nuclear Science Advisory Committee, “Report of the NSAC Ad Hoc Subcommittee on a 4 GeV, CW Electron Accelerator for Nuclear Physics,” September 27, 1984, JLL. See also: Westfall, “From Desire to Data” (ref. 1), 320–21, for more on the 1982 long-range plan.

  111. “Nuclei, Nucleons and Quarks, Nuclear Science in the 1990s: A Long Range Plan by the DOE/NSF Nuclear Science Advisory Committee,” December 1989, accessed April 16, 2017, https://science.energy.gov/~/media/np/nsac/pdf/docs/lrp_1989.pdf.

  112. “Conceptual Design Report Basic Experimental Equipment,” April 13, 1990, JLL, A1-2.

  113. Quotes, respectively, from Domingo, interview with Westfall (ref. 54), and Walecka, interview with Westfall (ref. 18).

  114. In addition to Kowalski, the TAP included K. Brown from SLAC, H. de Vries from NIKHEF, P. Debenham from NIST, B. Frois from SACLAY, J. Nolen from Michigan State University, J. Purcell from Advanced Cryomagnetics, P. Reardon from SAIC, H. A. Thiessen from Los Alamos National Laboratory, J. E. C. Williams from MIT, and A. Yamamoto from KEK.

  115. “Report of the Technical Advisory Panel on the High Resolution Spectrometers,” June 28–30, 1989, JLL, 3.

  116. Ibid., 5.

  117. Quotes, respectively, from ibid., 17, 5.

  118. Ibid., 17.

  119. “Nuclei, Nucleons, and Quarks” (ref. 111), 1.

  120. Walecka, interview with Westfall (ref. 18).

  121. In many experiments involving the coincident detection of one of the particles resulting from the interaction (for example, the proton in an (e,ep) reaction), the second spectrometer is restricted to detection of the particle in the scattering plane. If the second spectrometer can be moved out of the scattering plane access is provided to very interesting aspects of the reaction that are not available from measurements in the scattering plane, providing further tests of the theory and new insights into the reactions taking place. The CLAS detector in hall B has this capability, but with modest resolution. Having the capability with a magnetic spectrometer such as the SOS in hall C would open new experiment possibilities. Text: Carlini, interview with Westfall (ref. 63).

  122. Carlini, interview with Westfall (ref. 63); L. S. Cardman and R. Carlini, “Progress Report and Planning Memo,” October 10, 1989, JLL.

  123. Quotes, respectively, from Carlini, interview with Westfall (ref. 63) and Domingo, interview with Westfall (ref. 54). See also: Catherine Westfall, interview with Hermann Grunder, July 10, 1996, JLL.

  124. Robert Lourie, “Important Message to all Hall Users,” August 3, 1989, JLL; Bernhard Mecking and Robert McKeown, “Report on End Station B Collaboration Meeting,” June 25, 1989, JLL; Cardman and Carlini, “Progress Report” (ref. 122).

  125. “Nuclei, Nucleons, and Quarks” (ref. 111).

  126. Quotes, respectively, from Carlini, interview with Westfall (ref. 63), and Cardman and Carlini, “Progress Report” (ref. 122).

  127. “Conceptual Design Report Basic Experimental Equipment,” April 13, 1990 (revised), JLL.

  128. Quote from Domingo, interview with Westfall (ref. 54).

  129. Hermann Grunder, interview with Catherine Westfall, June 19, 1995, JLL.

  130. “Conceptual Design Report Basic Experimental Equipment,” April 13, 1990 (revised), JLL.

  131. Quotes from Domingo, interview with Westfall (ref. 54); Mecking, speech Domingo Day (ref. 36); John Domingo, “Experimental Program,” Semi-annual DOE review, September 19–21, 1989, JLL.

  132. Grunder, interview with Westfall (ref. 123).

  133. “Report of the DOE Review Committee on the Sixth Semiannual Review of the Continuous Electron Beam Accelerator Facility (CEBAF, September 19–21, 1989,” October 30, 1989, JLL, 10.

  134. Ibid., 7.

  135. Ibid., 8.

  136. Domingo, interview with Westfall (ref. 21); Walecka, interview with Westfall (ref. 18). For more information on Grunder’s struggles to obtain funding and build the accelerator, see Westfall, “Two More Laboratories” (ref. 6).

  137. J. Dirk Walecka to file, October 14, 1989. The author thanks J. Dirk Walecka for this document.

  138. Ibid.

  139. Quotes, respectively, from ibid and John Schiffer, email to PAC4 members, October 26, 1989, Schiffer files, ANL. See also, appended documents to John Schiffer email to PAC4 members, October 26, 1989, Schiffer files, ANL.

  140. Quotes, respectively, from Walecka, October 14, 1989 (ref. 137) and Robert Lourie, memo to hall A Colleagues, December 6, 1989, JLL.

  141. John Schiffer, email to PAC4 members, October 26, 1989, Schiffer files, ANL.

  142. Ibid. See also: John Schiffer, letter to Kathy Strozak for J. Dirk Walecka and Hermann Grunder, Schiffer files, ANL.

  143. Catherine Westfall, interview with Nathan Isgur, October 22, 1998; J. Dirk Walecka, “Scientific Overview,” Semi-annual review, September 19–21, 1989, JLL.

  144. Domingo, interview with Westfall (ref. 21).

  145. Ingo Sick, email to John Schiffer, November 9, 1989, Schiffer files, ANL.

  146. John Schiffer, email to Ingo Sick, November 20, 1989, Schiffer files, ANL.

  147. J. D. Walecka, letter to J. Domingo, R. Carlini, B. Mecking, J. Mougey, L. Cardman, and K. Strozak, November 16, 1989, Schiffer files, ANL; John Schiffer to “Don” and “Hal,” December 16, 1989, Schiffer files, ANL. Nathan Isgur, interview with Catherine Westfall, October 22, 1998, JLL.

  148. Isgur, interview with Westfall (ref. 147).

  149. Domingo, interview with Westfall (ref. 21).

  150. Walecka, interview with Westfall (ref. 18).

  151. Quotes, respectively, from “Report of the CEBAF Program Advisory Committee 4,” April 1990, JLL, 1, 95.

  152. Quotes, respectively, from ibid., 95, 98.

  153. Ibid., 100–101.

  154. Domingo, interview with Westfall (ref. 54); John Domingo, letter to Hermann Grunder, March 15, 1990, Washington Correspondence, JLL and Hermann Grunder, letter to David Hendrie, February 17, 1990, JLL.

  155. Quotes from “Re: Hendrie’s Remarks to PAC, December 11, 1989,” Washington Correspondence, JLL; Grunder, letter Hendrie (ref. 154).

  156. “Re: Hendrie’s” (ref. 155).

  157. Mecking, interview with Westfall (ref. 39).

  158. Grunder, letter Hendrie (ref. 154); Grunder, interview with Westfall (ref. 50).

  159. Hermann Grunder, letter to James Decker, March 6, 1990, Washington Correspondence, JLL.

  160. James Decker, letter to William Wallenmeyer, March 13, 1990, Washington Correspondence, JLL.

  161. CEBAF, “Experimental Equipment Conceptual Design Report,” CEBAF R-90-001, JLL.

  162. The additional equipment designs in hall C for the hyper-nuclear spectrometer system, the Symmetric Toroidal Array Spectrometer (STAR), and a Parity Violation Experiment (PAVEx) were not included in the initial complement of equipment; however, large-scale apparatus was eventually constructed for each of these physics programs. Text references: CEBAF, “CEBAF Design Report,” May 1986, JLL; CEBAF, “Experimental Equipment Conceptual Design Report,” CEBAF R-90-001, JLL.

  163. CEBAF, “Experimental Equipment Conceptual Design Report,” CEBAF R-90-001, JLL.

  164. J. Dirk Walecka, memo to the CEBAF user’s group,” June 12, 1990, JLL.

  165. Domingo, interview with Westfall (ref. 21).

  166. “Report of the DOE Review Committee on the Seventh Semiannual Review of the Continuous Electron Beam Accelerator Facility,” April 24–26, 1990, JLL, 6–7.

  167. Ibid., 14.

  168. J. Dirk Walecka, memo to the CEBAF user’s group,” June 12, 1990, JLL.

  169. Wilmot Hess, letter to Peter Paul, May 25, 1990. The author thanks Lawrence Cardman and Brenda May for this document.

  170. Quote from Peter Paul, letter to Wilmot Hess, July 10, 1990, JLL. See also: “Evaluation of CEBAF Equipment Plan by the Nuclear Science Advisory Committee, July 7, 1990.” The author thanks Lawrence Cardman and Brenda May for these documents.

  171. Sherman Fivozinsky, interview with Catherine Westfall, November 18, 1996, JLL; Mecking, interview with Westfall (ref. 39); Grunder, interview with Westfall (ref. 50).

  172. All the tables in the appendices are taken from a series of tables presented in Lawrence Cardman, “Background Information for History Articles on the Evolution of the Science Program at Jefferson Lab and the Planning for the Experimental Equipment,” JLab Technical Note, JLL. As the technical note explains, the tables are based on a rigorous examination and comparison of the physics goals mentioned in various planning documents, noted in the tables. This document explains the process for establishing common language for physics goals so that a comparison could be made.

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Acknowledgments

This article was written for Jefferson Science Associates, LLC, under US DOE Contract No. DE-AC05-06OR23177. The author received support for the interviews conducted in 2012 and thereafter from a grant-in-aid from the Friends for the Center for the History of Physics, American Institute of Physics. Earlier interviews were supported by Jefferson Science Associates. The US Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for US Government purposes. The author wishes to thank Bernhard Mecking, John Schiffer, J. Dirk Walecka, and in particular, Lawrence Cardman, for much technical information and assistance. She also wants to thank Peter Pesic, Robert Crease, and Joe Martin for their patient and astute editing.

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Correspondence to Catherine Westfall.

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Catherine Westfall, a professor at Michigan State University, has written numerous publications on the history of national laboratories including co-authored books on the development of the first atomic bombs at Los Alamos and the history of Fermilab.

Appendices

Appendix 1: The Evolution of the Science Motivations from the 1975 NRC Panel to the 1982 SURA Proposal

This table shows wish lists of experiments from the 1982 proposal by the Southeastern Universities Research Association (SURA) that led to the formation of the laboratory, as well as the experiments promoted by the 1975 National Research Council, the 1977 study group chaired by Robert Livingston, the 1981 Blue Book report that emerged from the 1979 meeting of the Bates accelerator users group, and the 1982 NSAC panel chaired by Peter Barnes.172

Physics Topic

Experiment Type

Physics Description

1975 NRC *

1977 Livingston

1979 LRP

1981 Blue Book

1982 Barnes

1982 SURA Proposal

I. Nucleon Structure

       

 A. Elastic scattering (e,e) from free nucleons

To measure the charge and current distributions of the nucleon (both polarization transfer technique and Rosenbluth) as a key ingredient for nuclear theory and, in particular, comparison of nuclear models with precise electron scattering data

II. The QCD Structure of the Hadrons

       

 A. Elastic scattering (e,e) from hadrons

To measure the charge and current distributions (both polarization transfer technique and Rosenbluth) as fundamental tests of QCD calculations of their structure

  

Mentioned, but no detailed expt.

 B. Tagged photon-excitation (γ t ,x) of the hadrons

Excited state structure of the hadrons as a testing ground for QCD descriptions of their structure

    

Mentioned; but not encouraged

 C. Electro-excitation (e,ex) of the hadrons

Excited state structure of the hadrons as a testing ground for QCD descriptions of their structure, with additional information from transition densities and differing multipole sensitivities

      

 D. DIS from quarks in free hadrons

i. Measure PDFs (spin independent and spin dependent and their integrals) to test QCD calculations of hadron structure

      
 

ii. Exclusive [e.g. (e,eγ)] and semi-inclusive [e.g. meson production] reactions in the DIS regime to enable 3D imaging of the hadrons’ quark structure in coordinate and momentum space through determination of generalized parton distributions (GPDs) and Transverse Momentum Dependent parton Distributions (TMDs)

      
 

iii. To explore the duality of the partonic and hadronic descriptions of strong interaction physics

      

 E. Parity violating elastic scattering from hadrons

To measure the weak neutral currents (WNC) of the hadrons, and then to study their strangeness content

   

WNC only

WNC only

 

III. Nuclear Structure

       

 A. Elastic scattering (e,e)

       

  1. From few-body nuclei

Tests of ab initio nuclear theory based on hadronic degrees of freedom (including meson and relativistic effects) searching for the limits of the applicability of that theory and the onset of quark degrees of freedom

  2. From complex nuclei

Measurements of the nuclear charge and current densities as tests of other approaches to nuclear structure calculations (beyond ab initio, which is applicable only to light nuclei). More generally, the goal is to explore the limits of a hadronic description of nuclei.

 

 B. Inelastic scattering (e,e′) and electro-production (e,x) or photo-production (γ,x)

       

  1. From few-body nuclei

Searching for exchange currents and for the limits of applicability of traditional nuclear theory and the onset of quark degrees of freedom in nuclei

  2. From discrete and continuum states in nuclei

Nuclear Structure (discrete states)—as tests of other approaches to nuclear structure calculations (beyond ab initio, which is applicable only to light nuclei)

 

 C. Inelastic scattering (e,ex)

       

  1. From continuum states in nuclei

Nuclear Structure (Giant resonances)

  

  2. (e,ep) from nuclei

“Classical” (e,ep) to study nuclei “shell by shell”

  3. (e,e′2N) from nuclei

To study NN correlations more directly

 D. DIS from quarks in nucleons in nuclei

To measure NN correlations without FSI

      

 E. Parity Violating Electron Scattering

Determination of the weak neutral current structure of nuclei and study of the neutron distribution

 

hints

hints

 

hints

 F. Photo- (or electro-) production of hypernuclei

Nuclear structure with strangeness providing both access to deep hole states and complementary information (from comparing ΛN to NN) on the origins and character of the NN force. (complementary to traditional pion production)

 

IV. The QCD Structure of Nuclei

       

 A. Elastic Scattering from few-body nuclei

Searching explicitly for the limits of ab initio nuclear theory (including relativistic and meson effects) and the onset of quark degrees of freedom

   

 B. Inelastic Scattering from and photo-disintegration of few-body nuclei

Searching for the onset of quark degrees of freedom in nuclei

   

 C. DIS from quarks in nucleons in nuclei

A window on the quark substructure of complex nuclei from the observation of deviations from single nucleon additivity (EMC effect, etc.).

    

 

 D. Elastic scattering (e,ep) from nucleons in nuclei

To examine differences between free nucleons and nucleons in the nuclear medium

      

 E. Photo- and electro-production of vector mesons and baryons off nuclei

Electro- and photoproduction of ρ, ω, and ϕ mesons with polarized electron beams can extend our knowledge of the spin properties of vector meson couplings to nucleons and to understand shadowing, exchange currents, and the short-range NN force.

   

 F. Photo- and electro-production of Δ and N* off nuclei (more generally, of mesons and baryon resonances)

Focused on the nucleon excitations as components of the nuclear wave function important at high Q, for nuclear forces, and for an eventual quark-gluon description of nuclear structure.

✔(but not QCD)

 

V. Standard Model Tests

       

 A. Parity violating (e,e)

Searches for parity violating amplitudes in high q elastic electron scattering on nuclei test modem theories of the weak interaction.

  

  1. Notes:
  2. * The Friedlander panel was charged in 1975 and held meetings in 1975, 1976, and 1977. Its final report was issued in 1977. We denote it here as NRC75 because its influence on the community was already evident by the end of 1975.
  3. 1. EMC effect discovered in 1983
  4. 2. Prescott parity violating (e,e) published in 1978

Appendix 2: The Science Motivation from the Original SURA 1982 Proposal and That of the First Program Advisory Committee

This table shows the wish list of the 1982 proposal for the Southeaster Universities Research Association that led to the formation of JLab as well as the wish list for JLab’s first Program Advisory Committee.

Physics Topic

Experiment Type

Physics Description

1982 SURA Proposal

1987 PAC1

I. Nucleon Structure

   

 A. Elastic scattering (e,e) from free nucleons

To measure the charge and current distributions of the nucleon (both polarization transfer technique and Rosenbluth) as a key ingredient for nuclear theory and, in particular, comparison of nuclear models with precise electron scattering data

II. The QCD Structure of the Hadrons

   

 A. Elastic scattering (e,e) from free hadrons

To measure the charge and current distributions (both polarization transfer technique and Rosenbluth) as fundamental tests of QCD calculations of their structure

 B. Tagged photon-excitation (γ t ,x) of the hadrons

Excited state structure of the hadrons as a testing ground for QCD descriptions of the them

 C. Electro-excitation (e,ex) of the hadrons

Excited state structure of the hadrons as a testing ground for QCD descriptions of their structure, with additional information from transition densities and differing multipole sensitivities

 

 D. DIS from quarks in free hadrons

i. Measure PDFs (spin independent and spin dependent and their integrals) to test QCD calculations of hadron structure

  
 

ii. Exclusive [e.g. (e,eγ)] and semi-inclusive [e.g. meson production] reactions in the DIS regime to enable 3D imaging of the hadrons’ quark structure in coordinate and momentum space through determination of generalized parton distributions (GPDs) and Transverse Momentum Dependent parton Distributions (TMDs)

  
 

iii. To explore the duality of the partonic and hadronic descriptions of strong interaction physics

  

 E. Parity violating elastic scattering from hadrons

To measure the weak neutral currents (WNC) of the hadrons, and then to study their strangeness content

 

III. Nuclear Structure

   

 A. Elastic scattering (e,e)

   

  1. From few-body nuclei

Tests of ab initio nuclear theory based on hadronic degrees of freedom (including meson and relativistic effects) searching for the limits of the applicability of that theory and the onset of quark degrees of freedom

  2. From complex nuclei

Measurements of the nuclear charge and current densities as tests of other approaches to nuclear structure calculations (beyond ab initio, which is applicable only to light nuclei). More generally, the goal is to explore the limits of a hadronic description of nuclei

  

 B. Inelastic scattering (e,e′) and electro-production (e,x) or photo-production (γ,x)

   

 1. From few-body nuclei

Searching for the limits of applicability of traditional nuclear theory and the onset of quark degrees of freedom in nuclei

 2. From discrete and continuum states in nuclei

Nuclear Structure (discrete states)—as tests of other approaches to nuclear structure calculations (beyond ab initio, which is applicable only to light nuclei)

  

 C. Inelastic scattering (e,ex)

   

  1. From continuum states in nuclei

Nuclear Structure (giant resonances)

 

  2. (e,ep) from nuclei

“Classical” (e,ep) to study nuclei “shell by shell”

  3. (e,e′2N) from nuclei

To study NN correlations more directly

 D. DIS from quarks in nucleons in nuclei

To measure NN correlations without FSI

 

 E. Parity Violating Electron Scattering

Determination of the weak neutral current structure of nuclei and study of the neutron distribution

 

 F. Photo- (or electro-) production of hypernuclei

Nuclear structure with strangeness providing both access to deep hole states and complementary information (from comparing ΛN to NN) on the origins and character of the NN force. (complementary to traditional pion production)

IV. The QCD Structure of Nuclei

   

 A. Elastic Scattering from few-body nuclei

Searching explicitly for the limits of ab initio nuclear theory (including relativistic and meson effects) and the onset of quark degrees of freedom

 B. Inelastic Scattering from and photo-disintegration of few-body nuclei

Searching for the onset of quark degrees of freedom in nuclei

 C. DIS from quarks in nucleons in nuclei

A window on the quark substructure of complex nuclei from the observation of deviations from single nucleon additivity (EMC effect, etc.).

 

 D. Elastic scattering (e,ep) from nucleons in nuclei

To examine differences between free nucleons and nucleons in the nuclear medium

 

 E. Photo- and electro-production of vector mesons and baryons off nuclei

Electro- and photoproduction of ρ, ω, and ϕ mesons with polarized electron beams can extend our knowledge of the spin properties of vector meson couplings to nucleons and to understand shadowing, exchange currents, and the short-range NN force.

 F. Photo- and electro-production of Δ and N* off nuclei (more generally, of mesons and baryon resonances)

Focused on the nucleon excitations as components of the nuclear wave function important at high Q, for nuclear forces, and for an eventual quark-gluon description of nuclear structure.

 

V. Standard Model Tests

   

 A. Parity violating (e,e)

Searches for parity violating amplitudes in high q elastic electron scattering on nuclei test modem theories of the weak interaction.

✔ (but 2nd Generation Expts.)

  1. Notes:
  2. * MIT Proposal references Blue Book, and does not provide other details, so I have used the Blue Book entries for the MIT proposal in this table
  3. 1. EMC effect discovered in 1983
  4. 2. Prescott parity violating (e,e) published in 1978

Appendix 3: Evolution of the Science Motivation from the Early NRC Report Through the 1986 CEBAF Design Report and the First (1987) Program Advisory Committee Meeting

This table shows the wish lists from: the early advisory committees; the 1982 Southeastern Universities Research Association proposal that led to JLab; JLab’s first Program Advisory Committee; and the 1990 DOE-approved experimental equipment conceptual design report that was used as a guide to develop the laboratory’s initial complement of experimental equipment.

Physics Topic

Experiment Type

Physics Description

1975 NRC *

1977 Livingston

1979 LRP

1981 Blue Book

1982 Barnes

1982 SURA Proposal

1987 PAC1

1990 Expt. Equip CDR

I. Nucleon Structure

         

 A. Elastic scattering (e,e) from free nucleons

To measure the charge and current distributions of the nucleon (both polarization transfer technique and Rosenbluth) as a key ingredient for nuclear theory and, in particular, comparison of nuclear models with precise electron scattering data

A, C

II. The QCD Structure of the Hadrons

         

 A. Elastic scattering (e,e) from hadrons

To measure the charge and current distributions (both polarization transfer technique and Rosenbluth) as fundamental tests of QCD calculations of their structure

  

Mentioned, but no detailed expt.

A, B, C

 B. Tagged photon-excitation (γ t ,x) of the hadrons

Excited state structure of the hadrons as a testing ground for QCD descriptions of their structure

    

Mentioned; but not encouraged

B

 C. Electro-excitation (e,ex) of the hadrons

Excited state structure of the hadrons as a testing ground for QCD descriptions of their structure, with additional information from transition densities and differing multipole sensitivities

      

B

 D. DIS from quarks in free hadrons

i. Measure PDFs (spin independent and spin dependent and their integrals) to test QCD calculations of hadron structure

        
 

ii. Exclusive [e.g. (e,eγ)] and semi-inclusive [e.g. meson production] reactions in the DIS regime to enable 3D imaging of the hadrons’ quark structure in coordinate and momentum space through determination of generalized parton distributions (GPDs) and Transverse Momentum Dependent parton Distributions (TMDs)

        
 

iii. To explore the duality of the partonic and hadronic descriptions of strong interaction physics

        

 E. Parity violating elastic scattering from hadrons

To measure the weak neutral currents (WNC) of the hadrons, and then to study their strangeness content

   

WNC only

WNC only

 

C

III. Nuclear Structure

         

 A. Elastic scattering (e,e)

         

  1. From few-body nuclei

Tests of ab initio nuclear theory based on hadronic degrees of freedom (including meson and relativistic effects) searching for the limits of the applicability of that theory and the onset of quark degrees of freedom

A, C

  2. From complex nuclei

Measurements of the nuclear charge and current densities as tests of other approaches to nuclear structure calculations (beyond ab initio, which is applicable only to light nuclei). More generally, the goal is to explore the limits of a hadronic description of nuclei

   

 B. Inelastic scattering (e,e′) and electro-production (e,x) or photo-production (γ,x)

         

  1. From few-body nuclei

Searching for exchange currents and for the limits of applicability of traditional nuclear theory and the onset of quark degrees of freedom in nuclei

A, B, C

  2. From discrete and continuum states in nuclei

Nuclear Structure (discrete states)—as tests of other approaches to nuclear structure calculations (beyond ab initio, which is applicable only to light nuclei)

   

 C. Inelastic scattering (e,ex)

         

  1. From continuum states in nuclei

Nuclear Structure (Giant resonances)

  

  

  2. (e,e′p) from nuclei

“Classical” (e,ep) to study nuclei “shell by shell”

A, B

  3. (e,e2N) from nuclei

To study NN correlations more directly

B

 D. DIS from quarks in nucleons in nuclei

To measure NN correlations without FSI

      

 

 E. Parity Violating Electron Scattering

Determination of the weak neutral current structure of nuclei and study of the neutron distribution

 

hints

hints

 

hints

 

C: Hints of future studies w/ STAR (not built)

 F. Photo- (or electro-) production of hypernuclei

Nuclear structure with strangeness providing both access to deep hole states and complementary information (from comparing ΛN to NN) on the origins and character of the NN force. (complementary to traditional pion production)

 

C

IV. The QCD Structure of Nuclei

         

 A. Elastic Scattering from few-body nuclei

Searching explicitly for the limits of ab initio nuclear theory (including relativistic and meson effects) and the onset of quark degrees of freedom

   

A

 B. Inelastic Scattering from and photo-disintegration of few-body nuclei

Searching for the onset of quark degrees of freedom in nuclei

   

A, C

 C. DIS from quarks in nucleons in nuclei

A window on the quark substructure of complex nuclei from the observation of deviations from single nucleon additivity (EMC effect, etc.).

    

 

 

 D. lastic scattering (e,ep) from nucleons in nuclei

To examine differences between free nucleons and nucleons in the nuclear medium

      

B, C

 E. Photo- and electro-production of vector mesons and baryons off nuclei

Electro- and photoproduction of ρ, ω, and ϕ mesons with polarized electron beams can extend our knowledge of the spin properties of vector meson couplings to nucleons and to understand shadowing, exchange currents, and the short-range NN force.

   

B, C

 F. Photo- and electro-production of Δ and N* off nuclei (more generally, of mesons and baryon resonances)

Focused on the nucleon excitations as components of the nuclear wave function important at high Q, for nuclear forces, and for an eventual quark-gluon description of nuclear structure.

✔ (but not QCD)

 

 

B, C

V. Standard Model Tests

         

 A. Parity violating (e,e)

Searches for parity violating amplitudes in high q elastic electron scattering on nuclei test modem theories of the weak interaction.

  

✔ (but 2nd Generation Expts.)

C (but not built)

Appendix 4: The Experimental Equipment Included in the May 1986 CEBAF Design Report

Equipment Designs

Detector Characteristics

Comments

Included in Planning

Maximum Momentum P max (GeV/c)

Momentum Acceptance

p (%)

Resolution p/p δ p/p

Solid Angle (msr)

for Hall A

for Hall B

for Hall C

4 GeV/c reimaging spectrometer

4

10

≤ 10−4

10.8

    

4 GeV/c thin target spectrometer

4

10

≤ 10−4

10.8

 

Yes

  

4 GeV/c moderate resolution spectrometer

4

10

≤ 10−3

10.8

   

Yes

2.5 GeV/c thin target spectrometer

2.5

10

≤ 10−4

20

    

2.5 GeV/c moderate resolution spectrometer

2.5

15

≤ 10−3

20

   

Replaced with VAS as second spectrometer for hall C

1.2 GeV/c

1.22

20

≤ 2 × 10−5

35

 

Yes (in a pit so it can move in a full circle)

  

Large Acceptance Scintillator Hodoscope (LASH)

  

~ 5 × 10−3

 

Moderate resolution (~ 5 × 10−3) 0.2 m × 0.2 m hodoscope for hadron detection

Not stated explicitly: could use in A or C for triple coincidence experiments

 

Not stated explicitly: could use in A or C for triple coincidence experiments

Large Acceptance Detector (LAD)

    

Early design concept, w/ rectangular coils, covering of order 2π, for 107 γ/sec tagged photon beams (possibly electron beams as well)

 

Yes

 

Variable Acceptance Spectrometer

~ 3 GeV

Depends on details of experiment setup

Depends on details of experiment setup

~ 50 msr (0.75–2.0 GeV/c) reduced to 25 msr by 3 GeV/c

Large solid angle, and capable of moving out of plane (and much higher luminosity than LASH because it has a magnetic field between the target and detector package)

  

Yes

Polarized Targets

    

Dynamic Nuclear Polarization targets discussed, NH3 and ND3

   

Beamline Equipment

     

Beam Position Monitoring (BPM) System and Beam polarimeter

  

Appendix 5: Experimental Equipment Included in the April 1990 Experimental Equipment CDR

Equipment Designs

Detector Characteristics

Comments

Included in Planning

Maximum Momentum P max (GeV/c)

Momentum Acceptance Δ p (%) Δ p (%)

Resolution δ p/p

Solid Angle (msr)

for Hall A

for Hall B

for Hall C

4 GeV/c high resolution spectrometers (HRS)

4.0

9.9

5 × 10−5

9.9

Superconducting QQDQ spectrometer, somewhat simplified design (relative to the earlier approach) and both spectrometers to be identical (to reduce costs and technical risk)

Two, one with a detector package optimized for electrons and the second for hadrons (including a polarimeter)

  

CLAS (CEBAF Large Acceptance Spectrometer)

  

Ranges from 0.4% at 1 GeV/c, 20° to 0.8% at 1 GeV/c, 90°

Covers θ from 8° to 140°, with φ acceptance from 30% of 2π at 15° to 85% of 2π at 90°

A substantial evolution from the LAS design of the CDR. The Toroidal detector clearly capable of electron- AND photon-induced reaction studies. It now has shaped coils optimizing resolution and providing a 1m diameter field-free region for polarized targets

 

Yes (details in comments)

 

Photon Tagging system

4

Tags photons from 20% to 95% if the beam energy

10−3

   

Yes (essential for photon-induced reaction studies with CLAS)

 

High Momentum Spectrometer (HMS)

6.0

20

10−3

10

Capability of measuring particles above the beam momentum needed for reactions in which a final-state hadron is detected (e.g. deuteron photodisintegration)

  

Yes

Short Orbit Spectrometer (SOS)

1.5

40%

~ 8 × 10−4

9

Can be raised out-of-plane

   

Hyper-Nuclear Spectrometer System (HNSS)

    

An Enge split-pole for virtual photon tagging and a Kaon Spectrometer for (e,eK) measurements

  

Not part of what became the base equipment

Symmetric Toroidal Array Spectrometer (STAR)

        

Parity Violation Experiments at CEBAF (PAVEX)

        

Targets

     

High power cryotarget

 

Dynamic Nuclear

 Polarization targets discussed, NH3 and ND3

        

Beamline Equipment

     

Beam Position Monitoring (BPM) System and Beam polarimeter

  

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Westfall, C. From Desire to Data: How JLab’s Experimental Program Evolved Part 2: The Painstaking Transition to Concrete Plans, Mid-1980s to 1990. Phys. Perspect. 20, 43–123 (2018). https://doi.org/10.1007/s00016-018-0214-2

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Keywords

  • Conceptual Design Report
  • Approved Experiments
  • Walecka
  • Equipment Planning
  • Letter Of Intent (LOI)