Helmut Braun in the ‘80s

Hugh MontgomeryJefferson Laboratory

Colloquium in Memory of Helmut Braun

CERN, June 24, 2011

2

Outline

CERN Experiment NA9

Fermilab Experiment E665

I was Spokesman of EMC, which, during the time I was there, involved:

NA-2 Characterized by its forward spectrometer

NA-28 The very small angle scattering introduced by Sven Kullander,

Per Grafstrom et al. NA-9

The “full” experiment with a vertex magnet in addition to the FS magnet

As I recall, perhaps a little scurrilously, Danielle Treille and Bjorn Wiik were the SPSC referees

There was considerable emphasis on particle identification and we could tell that we would only be approved if we incorporated Aerogel in the design

This we did and Helmut jointed EMC to play a major role in the particle ID

CERN NA9

NA9 Collaboration

NA 9 Spectrometer

NA 9 Vertex Magnet and Cerenkov Counters

Helmut had two excellent Wuppertal students Heiner Bruck: went on to DESY to work on

the magnets for HERA & is still there Manfred Potsch: now Senior Consultant at

MPS Consult GmbH near Mannheim Helmut, and this was a characteristic,

was deep into the technical issues of gas Cerenkovs and gas recirculation; purification systems were the key

He developed a relationship with a CERN staff member, Michel Bosteels who became Helmut’s point of reference for such systems.

Helmut in NA 9

Helmut was really a renaissance man, at least in the sense that he followed with great appetite the appearance of fractals and chaos in the conversations of physicists

He and I often ate lunch, out of phase with most, at Tortella’s. Helmut inevitably advanced some new thoughts on the subject and its extensions, Mandelbrot and his set (beard & moustache).

Renaissance Man

This openness to mathematical treatments led him to push for something more sophisticated than the traditional analysis of the binary on-off states from the different particle ID detectors

This meant introducing Bayesian statistics and of course convergence was slower

This frustrated me as spokesperson - the goal was to get results out, and quickly

Helmut was imbued with a bloody minded, almost self-destructive intellectual honesty which allowed him to ignore the raves & rants of people who merely wanted results

Renaissance Man

NA 9 Particle ID

 How the sensitive ranges of the different detectors interplayed

NA 9 Particle ID

 Resulting acceptance for different particles

NA 9 Fragmentation Functions

 Effort and innovation rewarded

.. And so to the New World ..

On to Fermilab, where Helmut became a family friend

The vertex detector, cerenkovs, etc were in from the beginning and again, Helmut went for the most sophisticated analysis of the particle ID detectors

He also became interested in personal computers; perhaps this had started earlier but he started playing with Atari devices

He got us into trouble by appearing in a magazine article (promoted at least by Atari) in which it seemed as though the whole of Fermilab relied on Atari personal computers to interact with the world…

Fermilab - E665

E665 Proposal When I asked Erwin

Gabathuler, who was our CERN boss at the time, whether we were really going to Fermilab, he replied:

“You must keep all your balls in the air …“

Perhaps you can guess at my reply....

E665 Spectrometer

Later the downstream Cerenkov became a RICH counter

The experiment used two ex-Cyclotrons, the Chicago Cyclotron as a magnet and the Rochester Cyclotron as

hadron absorber.

E665 NIM Paper Helmut’s student

Uwe Ecker, was the lead author of the first paper out of E665 on the z dependence of hadron production

Its fun to compare the two author lists…

There were feuds in both EMC and E665; Helmut was never in the eye of those storms, but he did push for intellectual excellence in our publication patterns

I believe he was very comfortable with the way that groups at Fermilab approached the physics. A bit more to his liking than, say, DELPHI…

Once, he approached me in my Fermilab

staff role to see whether there were opportunities for him to work at Fermilab. Nothing seemed to fit; or did I fail to find a fit??

Who knows?

Helmut Braun and Fermilab

I recall a man who enjoyed the social side of physics, who interacted well with people in general, who had enormous respect for competent technologists, and who looked to respect his colleagues and to seek reciprocation

I spoke to him last perhaps four or five years ago at CERN when I was there reviewing Atlas-UK. He had changed, but imperceptibly

Helmut’s Attribute(s)

I count myself privileged to be able to have called Helmut Braun a colleague    

Have fun when you talk about Helmut – I’m sorry I cant be there in person

Helmut was resilient in the face of adversity and would not support “wailing and gnashing of teeth”…

Helmut in retrospect