Paris 8 juin 2013 1Geneva 17 December2014

ISOLDE at 50

HAPPY BIRTHDAY TO YOU

From pre- ISOLDE to ISOLDE : some background and personal recollections

Torleif Ericson

A not so likely event

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The origin of ISOLDE goes back to Niels Bohr in 1952

1952: Niels Bohr persuades Alexis Pappas from Oslo to do Cern-related radiochemistry at the 180 MeV SC at Uppsala

1957: the 600 MeV SC starts operations at CERNA world class high energy machine though not highest in energy

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Nuclear Chemistry at CERN

1957:The SC director Gentner asks Pappas to assemble a Nuclear Chemistry Group

1958: Gösta Rudstam becomes its first leader; Pappas becomes a CERN advisor on nuclear chemistry for a decade

Remember: nuclear physics and nuclear chemistry are then closely related fields

General mission of the radio chemistry group (Memorandum 1961): measurements of fission and spallation cross sections at 600 MeV and 25 GeV to understand the mechanism of complex processes and for various practical purposes of other experiments.

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1958: The SC puts CERN on particle physics map

The first important CERN contribution:the confirmation of π- to e- + neutrino suppression by a factor ten thousand

Maria and Giuseppe Fidecaro with Alec Merrison and Helmut Paul

The Fidecaros 1963

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SC’s golden years of particle physics 1958-65

Many leading physicist preferred SC to the PS which started 1960

The SC was the perfect low energy pion and muon machine

Key discoveries and tests of weak interactions were ripe fruits

Some names on publications

G. Charpak, L. Dick, M. Fidecaro, C. Rubbia (very young), V. Soergel, V. Telegdi, A. Zichichi,

K. Winter together with some young theorists like N. Cabibbo and A. de Rujula

Machine time was vigorously fought for and allocated in hours, not shift

BUT TIME WAS OBVIOUSLY RUNNING OUT !

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The decisive rôle of Viki Weisskopf

Director general 1961-5; shaped the CERN traditions for decades

One of Weisskopf’s visions

A peril for particle physics: brilliant success and isolation from other science

A remedy: reestablished links to nuclear physics

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An initiative: The 1963 Conference on High Energy Physics and Nuclear Structure

A watershed and the birth of intermediate Energy Physics

Topics relevant for the SC 

Interactions of pions with complex nuclei T. E. O. Ericson

Fragmentation induced by high energy particles N. A. Perfilov

Muons and nuclear structure J. C Sens

Complex nuclei as a tool in elementary particle physics V. Telegdi

 

Viki Weisskopf closed the meeting with a call for proposals in nuclear physics at CERN.

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In parallel to ISOLDE a lively program using mainly low energy and stopped muons and pions in nuclear physics developed rapidly at the SC as a consequence of Weisskopf’s invitation .

In particular, the mesonic X-ray programs developed by Gerhard Backenstoss and Hans Sens skillfully exploited their non-commercial access to big GeLi detectors, gaining 2 orders of magnitude in resolution . They mostly were ahead of the US competition mainly from Mme Wu and James Rainwater at Columbia, but also from the Chicago group.

This however, is not real part of the background to ISOLDE.

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First trace of the on-line separator project:

Internal memorandum by G. Andersson and G. Rudstam November 19th 1963

After the Conference and Weisskopf’s call for proposals

A meeting of Weisskopf, Pappas, Rudstam and TE February 1964about possibilities mentions radio-isotopes at the SC by special techniquesfor short half-lives, Q-values and spectroscopy without any details.

A huge difference with experimental proposals:it concerns a facility and resources well beyond those of the Nuclear Chemistry Group

October 26th 1964 I recommend as an ‘expert’ the proposal to the Nuclear Physics Experiments Committee which encourages a final version

A polished version is approved on December 17th 1964

A meeting on April 10th organized by the Nuclear Chemistry discusses enthusiasticallyScientific aims and organization.

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Peter Preiswerk Nuclear Physics Division Leader 1964

Who were the crucial people who made it possible besides the initiators?

Most likely Wolfgang Gentner, Peter Preiswerk and Alexis Pappas

They had all important nuclear physics links in their career via the Joliot-Curie group in Paris

Viki Weisskopf played an important role as a major support strongly positive to the field.

Wolfgang Gentner Chairman of the CERN Scientific Policy Committee

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The ISOLDE program is no longer fragile and exposed to timely coincidences.

It is an integral part of CERN and will presumably last as long as CERN exists. 

GOOD LUCK ISOLDE FOR MANY FRUITFUL YEARS TO COME! 

Who would have guessed my wish to-day in 1964!