David Leith Symposium: Early Years From Scintillators to Bubble Chambers to Wire Chambers Michel Davier LAL, Université Paris-Sud, Orsay Michel Davier Dec.12 2014 David Leith Symposium, SLAC 1 Caveat: through his long and productive career David worked with a very large number of collaborators (as demonstrated by the impressive list of participants at this symposium). Through this short report I will be able to mention only a few. My apologies! Michel Davier Dec.12 2014 David Leith Symposium, SLAC 2 From Hutchesons Grammar School to Glasgow University (1959) The Glasgow University Cricket Team in the 50’s Michel Davier Dec.12 2014 David Leith Symposium, SLAC 3 Graduate in the Department of Natural Philosophy at Glasgow University 1962 Experiment on photoproduction on protons near threshold on the 330 MeV electron synchrotron with a scintillator telescope 4 papers published Thesis adviser: Gething Lewis Michel Davier Dec.12 2014 David Leith Symposium, SLAC 4 Postdoc at CERN (1962-1966) • • • • • Joined Max Ferro-Luzzi group: a good practice in scientific rigor First encounter with bubble chambers Studies of K±p interactions: start of a long-standing interest of David Productive period with 12 papers and many conference proceedings Remarkable results on hyperon spectroscopy (early demonstrations of SU(3) and the quark model) • First review paper with Bob Tripp, Adolf Minten, … 1964 Michel Davier Dec.12 2014 David Leith Symposium, SLAC 5 David joins SLAC: physics with bubble chambers • A young Associate Professor • Joins Joe Ballam’s group B • David gets involved in on-going activities… - analysis of data taken at BNL (16 GeV -p interactions) - shake-down of monochromatic photon beam at SLAC for further use with the 40” bubble chamber • but soon wants to have his own line of research • starts a collaboration with Alvarez’s group at LBL (Art Rosenfeld) • Exposures at Argonne with pions to improve situation of N phase shifts and baryon resonance spectroscopy (hot topic then) • Very elaborate analysis developed (K matrix) with Paul Söding and Roger Cashmore • First David’s student was on this work (Barbara Levi) • Very successful program with 8 papers published 1966 Michel Davier Dec.12 2014 David Leith Symposium, SLAC 6 A KL Experiment with the SLAC 40”HBC • David also pushed an original program with the 40” bubble chamber to study KL interactions, with Wes Smart, Bill Johnson,… • Innovative scintillator system for TOF • leading to 7 publications Michel Davier Dec.12 2014 David Leith Symposium, SLAC 7 From Bubble Chambers to Wire Chambers • Bubble chambers are detectors with full solid angle coverage and good spatial precision but slow • Event samples with high statistics, triggered in order to access specific processes with high sensitivity required fast electronic devices such as wire chambers • David got involved very early with such detectors, following experience gained at LBL in Perez-Mendez group • Spark chambers with magnetostrictive read-out were chosen (the famous wands, magic…) • Important contributors were Fatin Bulos, Harvey Lynch, and Steve Williams Michel Davier Dec.12 2014 David Leith Symposium, SLAC 8 Wire Chamber Spectrometer #1 • First experiment was on photoproduction on nuclei with Burt Richter and Victor Perez-Mendez with his student Steve Williams • A dependence determines the N total cross section • A good warmup with spark chambers Michel Davier Dec.12 2014 David Leith Symposium, SLAC 9 Wire Chamber Spectrometer #2 • This second experiment was on production by pions with Burt Richter • triggered by a sharp forward peak observed in photoproduction. • Blair Ratcliff and Brig Williams were students on this experiment • Same sharp forward peak is observed in the right helicity combination Michel Davier Dec.12 2014 David Leith Symposium, SLAC 10 Toward High Statistics Hadron Physics with Wire Chamber Spectrometers • The photoproduction and experiments were a good starting point to plan for future activities • It was also a good training ground for students and postdocs • David immediately realized the power of wire chambers spectrometers to pursue more effectively his interest in hadron spectroscopy and dynamics • Very low SLAC duty cycle was a priori not favorable compared to hadron machines • But David took up the challenge! • He initiated studies for a wide-aperture apparatus • While his vision of a very large spectrometer had still to wait for a while, a new version with a reduced scope was an important step capable of providing unique results • Thus a new two-prong experimental program started led by two newly appointed assistant professors in David’s group E-75: spectroscopy with K± beams (Bob Carnegie) E-85: K± p elastic scattering (MD) Michel Davier Dec.12 2014 David Leith Symposium, SLAC 11 The E-75/85 spectrometer #3 • • • • • Michel Davier Dec.12 2014 13 GeV RF-separated K beam and beam instrumentation Large aperture magnet 1.8 T 13 magnetostrictive chambers Proportional chambers Large segmented Cerenkov counter David Leith Symposium, SLAC 12 E-75 : K± interactions at 13 GeV • A rich program of strange meson spectroscopy • Discovery of two 1+ states: K1(1270)K, K2(1400)K* through PWA • Evidence for a 0- state at 1400 MeV (?) • Dynamics of 2-body processes Deck K2 K1 Michel Davier Dec.12 2014 Deck K2 K1 David Leith Symposium, SLAC 13 E-85 : K±/±/p± p elastic scattering • Obtain the C=-1 scattering amplitude by interference with the dominant C=+1 diffractive amplitude measure particle and antiparticle cross sections on protons with large statistics and small systematics • Dual absorptive model : cross over moves to smaller t at higher energies • 1mm spacing MWPC Michel Davier Dec.12 2014 David Leith Symposium, SLAC 14 New ideas and detector construction • During this period David was constantly thinking of new ideas for developing the best detectors and equipment to achieve the physics goals • The list of the projects he has initiated, pushed through and published is impressive: - wedge scintillator with high spatial precision - online Vidicon scanning system for bubble chambers - large aperture Cerenkov hodoscope - new digitizing and memory system for wire spark chambers - versatile high resolution beam position monitor - TOF trigger system for the 40” HBC - adaptable geometry low mass hodoscopes using cathode readout PC • A good technical team to realize the projects: Al Kilert, Bob Friday, Don McShirley, Ken Mauro, Bill Walsh… Michel Davier Dec.12 2014 David Leith Symposium, SLAC 15 Moving on to LASS (some personal memories) • LASS concept and physics studies started even before 1970 (with George Luste) • The story of the LASS adventure will be told by Bill Dunwoodie • I had the chance to participate in lively meetings in David’s office (with tables somewhat crowded by preprints) in the technical design phase • I was impressed by David’s strong leadership, yet in a friendly atmosphere, and his concerns over many detailed aspects (ex. discussion with John Alcorn about safety issues in case of a quench of the large solenoid: Boeing 747) • Another occasion I still vividly remember is a (AEC, ERDA?) review in Fall 1974 where David presented the status of the project and I was given the task to justify our interest in hadron spectroscopy. I used the quark model as an obvious framework, but was challenged by the reviewers on the basis that the SPEAR results had already disproved the model. Then came November 1974… Michel Davier Dec.12 2014 David Leith Symposium, SLAC 16 Friendships • • • • David created a unique friendly atmosphere in group B So many activities going on in parallel A multinational group David’s efficient leadership, yet leaving freedom to his collaborators, thus fostering their creativity • Frequent occasions to meet outside the lab - Tuesday night seminars at David’s home - Friday night beer at the Dutch Goose • David and Doreen legendary hospitality (also unique) • Ah, Doreen’s unforgettable Xmas Scottish shortbread…. • The famous New Year party in their house…. Michel Davier Dec.12 2014 David Leith Symposium, SLAC 17 Personal Friendship • Our two families have enjoyed a good friendship for 45 years • Shared memories: citing David on another occasion One of Doreen’s fondest memories, before her own grand-children arrived, was daily brushing the beautiful long hair of Eve and Diane, when their Mum and Dad had gone back to France on the death of Francoise’s father. • My daughters Diane and Eve still remember as well • We value very much the Leith friendship ~ 1969 Michel Davier Dec.12 2014 David Leith Symposium, SLAC 1974 18 1984 Thank you David for sharing this very productive part of your scientific life 2010 Thanks to Ewan and Mandi Patterson (and Doreen!), Harvey Lynch, and Jean Deken for some nice pictures! Michel Davier Dec.12 2014 David Leith Symposium, SLAC 19