Helen Edwards 1936–2016

Accelerator physicist Helen Edwards passed away on 21 June at her home in Illinois, US, aged 80. Her remarkable legacy includes the design and operation of high-energy accelerators around the world, to which her singular and indefatigable drive brought life to a variety of projects for five decades.

Helen completed her PhD in 1966 under the supervision of Boyce McDaniel at Cornell University, where she studied the associated photo-production of kaons. She then began her postdoctoral work with Robert Wilson, during which she managed the commissioning of Cornell’s 10 GeV electron synchrotron. Shortly thereafter, Wilson was appointed founding director of the National Accelerator Lab just outside of Chicago, which would be renamed Fermilab. Helen moved to the burgeoning Illinois lab in 1970, where her first responsibility was to bring the 8 GeV “Booster” proton synchrotron to full energy.

Helen then joined the design effort of the Fermilab “Energy Doubler”, which utilised high-field superconducting magnets to achieve proton energies of 1 TeV, and thus positioned the Tevatron as the world’s highest energy collider for the next 28 years. Helen also held the dubious honour of shutting down the Tevatron on 30 September 2011. Her contribution to the success of the Tevatron was acknowledged in 1989 by the US National Medal of Technology, the highest national honour for technological progress.

In 1989, Helen moved to the Superconducting Super Collider Laboratory in Texas and became the project’s technical director until late 1991. Soon afterwards, she was invited to DESY in Germany by Bjørn Wiik to assist him in the formation of the TESLA collaboration. Helen realised that, in addition to superconducting magnets, it was vital that superconducting technology be extended to radio-frequency cavities. Though conceived as an electron–positron linear collider based on superconducting accelerating structures, TESLA evolved into the FLASH facility, which is dedicated to the production of electron and photon beams for numerous studies such as biology and materials science. The DESY–Fermilab collaboration was a major factor in the success of FLASH.

In parallel to the development at DESY, Helen built a 15 MeV electron photoinjector laboratory at Fermilab. This machine provided an experimental platform for several advanced-accelerator concepts – including the first demonstrations of a round-to-flat beam transformer and transverse-to-longitudinal emittance exchange – and led to more than eight PhD theses in accelerator physics.

In every accelerator project that Helen led, she did so by example and in every aspect. She would perform calculations, turn wrenches, tune for beam and analyse data. Her insight was invaluable and deeply respected. She also made time to serve on advisory committees to CERN, Jefferson Laboratory, LNS at Cornell and the Facility for Rare Isotope Beams at Michigan State University. In addition to the Medal of Technology, her awards include a MacArthur Fellowship; election to the National Academy of Engineering; election to the American Academy of Arts and Sciences; and the Ernest Orlando Lawrence Award. Helen’s unparalleled genius, management skills, love for nature and adventure will be sorely missed.

• Timothy Koeth, University of Maryland.

Stephen Gasiorowicz 1928–2016

Stephen Gasiorowicz, best known for his contributions to the quark model of hadrons, the theory of glueballs and mechanisms of QCD confinement, and his role in co-founding the William I Fine Theoretical Physics Institute (FTPI) at the University of Minnesota, died on 3 June 3 aged 88.

Stephen was born on 10 May 1928 into a Jewish family in Danzig (currently Gdansk, Poland). With the rise of the Nazis in Germany in 1933, his family had to move to Warsaw. Then, when Germany invaded Poland on 1 September 1939, the Gasiorowiczes had to flee immediately. Stephen’s journey to freedom lasted for seven years and saw him pass through the USSR, Romania, Turkey, Iraq, Pakistan and India – where the family obtained residence permits that allowed Stephen to receive his education.

In 1946, the Gasiorowiczes were notified that their application for immigration to the US, which they had filed before the war, was finally approved. The same year, Stephen sailed from Calcutta to San Francisco with his mother and sister (his father had died in India). He was admitted to the University of California in Los Angeles as a physics major, where he later received his BA degree in 1948 and PhD in 1952. From 1952 to 1960, Stephen was employed by Lawrence Berkeley Laboratory at the University of California as a research staff member. In 1961, he moved to the physics department of the University of Minnesota, becoming a full professor in 1963, and he stayed there for the rest of his career.

Stephen acquired a reputation of an excellent lecturer and was sought after as a visiting professor by major research centres worldwide. Generations of physics students studied using the excellent textbooks he wrote, which include Elementary Particle Physics, Quantum Physics, and Physics for Scientists and Engineers. He was a PhD adviser to such prominent theoretical physicists as Stanley Brodsky at SLAC and William Bardeen at Fermilab.

Stephen was an intellectual and humanist with a broad knowledge of literature and arts, and his sense of humour was remarkable. He was also an absolutely great friend who was always available to help. Stephen will be missed tremendously.

• Mikhail Shifman and Arkady Vainshtein, University of Minnesota.

Victor Alexandrovich Karnaukhov 1930–2016

Prominent Russian scientist Victor Alexandrovich Karnaukhov passed away on 16 April after a long disease. Karnaukhov was a highly skilled physicist, applying ever-modern experimental methods and possessing fundamental theoretical knowledge in nuclear physics. A characteristic feature of his research was his choice of outstanding physical problems that could lead him to obtain qualitatively new results.

In 1954, after graduating from Moscow State University, Karnaukhov began working at the National Scientific Center in Moscow – the so-called Kurchatov Institute. The department was headed by G N Flerov, who created a team of future founders of the Laboratory of Nuclear Reactions (LNR) at JINR, where Karnaukhov moved in 1960 and was head of department until 1976.

While investigating the decay of 20Ne in 1962, Karnaukhov made the first observation of an essentially new type of radioactive decay: β-delayed proton radioactivity. His research group went on to find a number of proton emitters, and today there are around 100 known sources. The emission of delayed protons is a powerful tool to study nuclear structure, and the discovery earned Karnaukhov the USSR State Prize in 1975. Previously, he and his collaborators had also observed the polonium isomer 212Po, which is remarkable for its anomalous suppressed α-decay, and he also actively participated (together with S Polikanov) in the discovery and identification of spontaneous fission isomers of heavy nuclei. On the experimental side, Karnaukhov proposed and realised a new type of very fast, gas-filled mass separator at the LNR cyclotron, which ultimately enabled the discovery of more than 30 new short-lived isotopes – most of them delayed proton emitters.

In 1977, Karnaukhov became head of a department at the Laboratory of Nuclear Problems, where he initiated a large project concerning super-dense nuclei. Since the start of the 1990s, his main research interests were the detailed study of phase transitions in nuclear systems. Even today, a new project proposed by Karnaukhov is under way at the Laboratory of High Energy Physics, JINR, to study the fission of hypernuclei produced in collisions of relativistic deuterons with heavy targets. His scientific achievements are presented in more than 150 publications, and his studies of proton radioactivity are referred to in many textbooks, monographs and encyclopedias.

He had remarkable courtesy and helpfulness, and the ability to propose exciting scientific ideas and demonstrate firm principles when discussing challenging problems. Victor Karnaukhov will forever live in our memory.

• His friends, colleagues and the DLNP staff.

Pablo Rodríguez Pérez 1976–2016

Pablo Rodríguez Pérez, a physicist on the LHCb experiment, died suddenly on 1 July in Manchester, UK.

Pablo obtained his degree in physics at the Universidade de Santiago de Compostela (USC) in 2003, specialising in electronics, and then worked in industry. He joined the LHCb experiment in 2007, undertaking a MSc at USC during which he optimised the read-out electronics for the LHCb inner tracker. He then continued to his PhD studies, becoming the principal author of the experiment-control system of the silicon tracker. After the commissioning of the LHCb experiment, he moved his attention to the LHCb upgrade, performing the first investigation of prototypes for the upgrade of the vertex locator (VELO).

Following his PhD from USC, from which he graduated cum laude, Pablo joined the University of Manchester in 2013 to work further on the VELO upgrade. He took the lead role in the group’s FPGA firmware development and was key to the module construction for the VELO upgrade.

Pablo is survived by his wife, Sonia, and their three young children, his parents, and his brothers Iván and Carlos. He is predeceased by his brother Víctor. His warmth, kindness, dedication and competence will be deeply missed by his many friends in the LHCb collaboration.

• LHCb Collaboration.

Nikolai Maksimovich Shumeiko 1942–2016

On 15 June, Nikolai Maksimovich Shumeiko passed away at the age of 73, having been an outstanding scientist who was a member of the JINR Scientific Council and head of the Centre of Particle Physics and High Energy Physics of the Institute of Nuclear Problems.

Shumeiko was born on 22 September 1942 in Dubrovno, Belarus, and in 1966 he graduated in physics from Moscow State University. From 1970, he worked at Belarusian State University (BSU) at the physics department, at the Institute of Nuclear Problems BSU, and from 1993 he worked at the National Scientific and Educational Centre of Particle Physics and High Energy Physics, BSU, which was founded on his initiative.

He made a fundamental contribution to the universal covariant approach (the “Bardin–Shumeiko” method) to account for radiative corrections in observed values of particle interactions. Other research interests included spin physics. He was deeply involved in the design and production of important calorimetric, muon and magnetic subsystems for the CMS and ATLAS detectors at the LHC. Shumeiko was the founder of a scientific school in particle physics in Belarus and author of more than 600 papers, with an impressive Hirsch index of 54. For many years, he was responsible for the co-operation of scientific institutes and industrial enterprises in the Republic of Belarus with leading scientific centres such as JINR and CERN, and he was an official representative of the Republic of Belarus in many large experimental collaborations, including CMS, ILC and CLIC.

Shumeiko won several awards for his research and organisational activities, among them the Francysk Skaryna Medal, the Order of Friendship of the Russian Federation, Honorary Certificate of the Council of Ministers of the Republic of Belarus, and the Academician F Fedorov Prize of NAS Belarus.

Nikolai Shumeiko was a wonderful man whose unique talent, profound knowledge and exceptional diligence for many years served the basis for the national development of elementary particle physics. He led dozens of young people to science, and his competence, honesty and self-discipline were always a bright example for us.

• The JINR directorate, scientific community of the Institute of Nuclear Problems BSU, pupils and friends.

Guido Vegni 1931–2016

Guido Vegni, a renowned Italian particle physicist at the University of Milan, passed away on 2 June. With his death we have lost a friend, an excellent physicist and a strong supporter of the CERN programme.

Guido’s long and fruitful involvement in particle physics started in 1956 when he joined the Milan Nuclear Emulsion Group led by Giuseppe Occhialini. His thesis aimed to measure the spin-parity assignment of the K+ meson from its decay into three pions, contributing to the study of the famous “tau-theta puzzle”, which was eventually solved by the discovery of the non-conservation of parity in weak interactions. In 1960, Guido was appointed as assistant to Occhialini, which led to him eventually becoming the chair of elementary particle physics at Milan – a position he held until his retirement in 2006.

From 1963 to 1966, working as a CERN fellow, Guido joined the Saclay 81 cm bubble-chamber experiment, where he participated in the discovery of the ρ3(1690) meson.

At the end of the 1960s, a “live” target composed of silicon detectors was built by the Milan group and used for the first time in an experiment to study the diffractive dissociation of mesonic states on different kinds of nuclei. In the 1970s, Guido took part in several experiments at the Serpukhov accelerator in Russia, using a large magnetic spectrometer. The live target in this experiment allowed the detailed study of several states produced diffractively in the interactions between pions and nuclear targets, leading to the observations of two states – π(1300) and π(1800) – that were interpreted as radial excitations of the pion.

During the 1980s, Guido and his group moved to the DELPHI experiment at CERN’s Large Electron–Positron (LEP) collider, where they played a pioneering role in the silicon micro-vertex detector. After LEP, his interest turned to the LHC, and Guido became an enthusiastic supporter of the ATLAS experiment. He led the Milan group engaged in the design and construction of the ATLAS silicon pixel detector and made significant contributions to this effort.

Alongside his research, Guido was a passionate teacher and educator who motivated many students to follow research careers. He was convinced of the need to improve the quality of science teaching from primary school onwards, and promoted a successful training course for physics educators, which relied on tools that anticipated the internet and the IT revolution.

Our warmest sympathy goes to his wife Anita, his daughters Isabella and Giulia, and his son Ferdinando, together with their families. We will all miss Guido sorely.

• His friends and colleagues.