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GSI Scientific Report 2005
GSI Report 2006-1

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The front cover shows an artist's view of the High Acceptance Dielectron Spectrometer HADES installed in the target hall served by the SIS18 accelerator. The spectrometer detects rare leptonic decays of neutral vector mesons which are produced in the central reaction volume of heavy-ion collisions. The detector is capable of digitizing and filtering all relevant signals produced by reaction products at collision rates of up to 20 kHz. The detectors, which are moved apart along the beam axis in the image, are packed closely around the target for experiments to achieve polar angle coverage between 18 and 85 degrees. Six superconducting coils provide a toroidal magnetic field with a maximum bending power of 0.3 Tm.
So far, the electron pair (i.e. e⁺ e^-) production has been investigated in C+C, Ar+KCl and p+p reactions. The pair emission rate was measured over almost six orders of magnitude in the pair invariant mass range between 50 and 1000 MeV/c² (spectrum shown in the foreground). The experimental data clearly evidences contributions to the pair yield from the early phase of the collision. Information about the properties of mesons imbedded in dense nuclear medium can be obtained by careful analysis of the spectral distribution of emitted electron pairs. Elementary reactions are exploited to scrutinize our knowledge about the various emission processes. The histogram in the background exemplarily shows the exclusive reconstruction of η-meson production in p+p reactions. HADES will continue its experimental program with p and π-induced reactions, and, after replacing the inner time-of-flight system by a novel RPC detector and upgrading the data acquisition system, with experiments addressing heavier collision systems. pdf

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Imprint
Foreword
Detailed Contents

The FAIR project

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FAIR-GENERAL FAIR-APPA-BIOMAT FAIR-APPA-FLAIR FAIR-APPA-HEDGEHOB FAIR-APPA-SPARC FAIR-NUSTAR-ELISE FAIR-NUSTAR-EXL FAIR-NUSTAR-DESPEC FAIR-NUSTAR-LASPEC FAIR-NUSTAR-HISPEC FAIR-NUSTAR-ILIMA FAIR-NUSTAR-LEB FAIR-NUSTAR-MATS FAIR-NUSTAR-R3B FAIR-NUSTAR-SuperFRS FAIR-QCD-CBM FAIR-QCD-PANDA FAIR-QCD-PAX FAIR-ACC FAIR-SAFETY

HANU

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ACC-STATUS ACC-R+D NUSTAR-SPECTROSCOPY NUSTAR-EXOTIC-BEAMS NUSTAR-THEORY NUSTAR-SHE-PHYS NUSTAR-SHE-CHEM NQMA NQMA-EXPERIMENTS NQMA-THEORY INSTRUMENTS-METHODS

PNI

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AP-EXP-SPECTROSCOPY AP-EXP-COLLISIONS AP-METHODS AP-THEORY PLPY PLPY-EXP PLPY-METHODS PLPH-THEORY MATERIALS PHELIX RAD-BIOPHYSICS EXTERNAL-HIT

Annex

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ANNEX-PUBL ANNEX-COLLABORATIONS ANNEX-EVENTS ANNEX-UNIV ANNEX-EXPERIMENTS ANNEX-ORGANIGRAM
List of authors

Foreword

This year's Scientific Report shows a noticeable increase in the number of contributions, a trend already seen last year. The reason for this will be no surprise: with preparations for the Facility for Antiproton and Ion Research (FAIR) a broad range of additional research and development has started, both in the accelerator area as well as in the preparation of the experimental program. These are included in the present Report. In the future, once FAIR is formally formed, we expect that this will lead to a separate annual report. At present, however, during the so-called preparatory phase for FAIR, it seems that the most expedient way to distribute information is as a part of the annual GSI Scientific Report.
FAIR went through major developments over the last twelve months. 'Technical Reports' for all components related to accelerators, infrastructure, and civil construction, as well as 'Technical Proposals' for the experiments were prepared for the beginning of 2005. They were subsequently carefully reviewed and scrutinized by high-level expert committees, with members from leading laboratories around the world. Key aspects were feasibility, appropriateness for the specific task, forefront technology, scientific and technical soundness, and realistic estimates of effort and cost. This has resulted in the so-called Baseline Technical Report (BTR), with more than 3000 pages and about 2400 authors. The BTR is now complete and, after approval by the FAIR Steering Committee which represents all international partners of FAIR, will be distributed this summer. The present Report provides, in its traditional form of short summary pages, many of the R&D details but also in its totality an overview of the current scientific and technical status of FAIR.
While the FAIR activities have required a very substantial effort from everybody involved, the ongoing program at the existing GSI accelerators has continued at full level and with a large number of interesting results.
Developments at the accelerators, from ion sources, beam diagnostics, beam dynamics of high-intensity beams up to new modes of operation for the storage ring, have increased accelerator performance and operation. 2005 saw record target times with beams on target of 6132 h at the UNILAC, 6315 h at SIS-18, and 1374 h at the ESR.
In nuclear structure research a set of radioactive-beam experiments with the RISING detector provided new spectroscopic results via relativistic Coulomb excitation for a range of nuclei: from light mirror nuclei to heavy nuclei, both neutron and proton rich. A surprising result was obtained from the analysis of previous data from the on-line mass separator at the UNILAC: two-proton decay from a long-lived high-spin isomer was unambiguously observed and reveals unexpectedly strong proton-proton correlations. The experimental nuclear structure work is supported by a range of theoretical calculations. An important component of this work is related to nuclear astrophysics. The previously developed Fermionic Molecular Dynamics (FMD) model for nuclear structure is being extended for resonance and scattering reactions. A new, antineutrino induced nucleosynthesis process, the νp-process, has been recently suggested to occur in supernova explosions and to drive the production of medium mass nuclei.
In nuclear matter research, interesting results now emerge from the analysis of recent heavy-ion (C+C) and proton (p+p) collision experiments at GSI with the HADES di-electron spectrometer. In the 2 AGeV Ar+KCl run in August 2005 almost complete coverage with the outer multi-drift chambers and thus good momentum resolution was achieved. This is confirmed by narrow peaks observed in missing-mass distributions, which permit the exclusive reconstruction of η-production in pp reactions. The C+C measurements show an enhancement of di-electrons over conventional sources at intermediate masses. Analysis of previous SPS experiments at CERN with GSI participation show scale dependence of mean transverse momentum fluctuations, an observable considered important for the determination of the critical point on the hadron-to-quark gluon plasma phase boundary (CERES), and production yields for phi mesons (NA49) which indicate non-smooth behavior similar to what was observed earlier for negative kaons. An analysis of all existing data on hadron production in a thermal model provides an updated freeze-out curve which tentatively indicates intriguing structure in the region towards higher baryochemical potential. Also in the nuclear-matter area the experiments are paralleled by intensive theoretical work, ranging from various approaches to the QCD phase diagram, to the calculation of spectroscopic functions of hadrons in the nuclear medium, and to transport calculations of the collision processes.
In atomic physics, work has continued to focus on radiative processes and high-resolution spectroscopy in highly-stripped very heavy atoms. Dielectronic recombination has been successfully established as a novel, effective and precise tool to measure isotope shifts. The work on traps has continued with ISOLTRAP at ISOLDE. with precision measurements of medium-mass nuclei on the neutron-rich side. At GSI, SHIPTRAP started its routine operation. SHIPTRAP is pursuing atomic and nuclear properties of heavy elements, produced in heavy-ion fusion reactions and with charge numbers greater than 100. As a first step, the masses of more than 20 nuclei were determined near the proton dripline around mass 147 and around ¹⁰⁵Sn near the rp-process end point. The experimental work goes parallel with developments in instrumentation, including in particular significant advances in the development and construction of the HITRAP facility. Theoretical support is provided by calculations of both, atomic collision processes and related spectroscopy and of fundamental aspects of QED and general symmetries.
Progress in plasma physics has been made in experimental investigations of heavy-ion beam generated states of high energy density in matter (warm dense matter, WDM). Recent developments of diagnostics tools and methods have provided for new data on thermo-physical and hydrodynamic responses of high-energy density states near the boiling curve, the regions of two-phase liquid-gas and the critical point.
Major progress has been achieved in the physics and engineering design efforts and construction of the PHELIX petawatt laser project at GSI. Technical developments were concerned with the pulsed power and control system of the preamplifier, extensive operation tests of the main amplifiers, in-situ inspections of large-sized lenses (involving an illumination and an image processing system, both specifically designed or this purpose), the general PHELIX control system, the petawatt compressor, beam diagnostics and simulations of pulse propagation. In terms of physics performance, a grazing incidence pumped zirconium x-ray laser was experimentally demonstrated at the PHELIX lasers. Recently a first experiment for proton beam generation was performed. The theory effort in plasma physics is closely connected to the experimental studies in terms of extensive simulations and phase diagram studies.
The material science work at GSI on ion tracks continues with the characterization and improved understanding of irradiated materials such as, for example, the ionic conduction and rectification properties in conical nanopores. A new major focus is on the production and investigation of the basic physical properties of nano-structures. These include, among others: the demonstration of Rayleigh instabilities during isothermal heating of metallic nanowires (considered important for future nano-scale devices); infrared and electrical transport properties of single nanowires with a manifestation of quantum size effects; and the production of sharp metallic nanotips.
The bio-physical and bio-medical research program continues along two major thrusts: the basic studies of biological systems to ionizing radiation and the tumor therapy activities. DNA fragmentation, in particular double strand breaks (DSB), were investigated in atomic force and scanning tunneling microscope high-resolution studies, together with other experiments on characterization and repair of DSB. Cell behavior, chromosomal aberrations and genetic instabilities, low- and high-dose effects, bystander responses, tumor cell migration are other examples of a broad and unique research program in radiation biology.
Tumor therapy at the pilot facility at GSI continued in 2005. By now, well above 300 patients have been treated (which involves more than 5000 field settings, more than 3000 fractions and individual treatments). New indications, such as prostate tumor, have been approved for treatment. Technical developments have continued which are directed at various topics, such as multiple field optimization procedures, irradiation of moving organs, detector optimizations and reconstruction algorithms for PET scanners etc.
The Heidelberg ion beam cancer therapy centre HIT, for which GSI has technical project responsibility, has seen major progress. The accelerator section of the building was completed to the point that installation of accelerator components started in the last quarter of 2005. Many factory acceptance tests of accelerator components have been performed as well as numerous commissioning activities at GSI.
This brief survey of the present Report can only provide a small glimpse into the various areas of activities. There are many more excellent examples that could not be touched upon within the scope of this introduction. The reader is encouraged to explore the full Report. As previously, the enormous amount of high-quality research and innovative technical developments - with respect to the ongoing program as well as for FAIR - would definitely not have been possible were it not for the broad involvement and dedication of the research community, the GSI users and the GSI staff. This is an opportunity to express our heartfelt thanks to everybody involved!

W. Henning
Scientific Director

GSI Scientific Report 2005GSI Report 2006-1

Cover illustration:

Contents

Foreword

FAIR-GENERAL

FAIR-APPA-BIOMAT

FAIR-APPA-FLAIR

FAIR-APPA-HEDGEHOB

FAIR-APPA-SPARC

FAIR-NUSTAR-ELISE

FAIR-NUSTAR-EXL

FAIR-NUSTAR-DESPEC

FAIR-NUSTAR-LASPEC

FAIR-NUSTAR-HISPEC

FAIR-NUSTAR-ILIMA

FAIR-NUSTAR-LEB

FAIR-NUSTAR-MATS

FAIR-NUSTAR-R3B

FAIR-NUSTAR-SuperFRS

FAIR-QCD-CBM

FAIR-QCD-PANDA

FAIR-QCD-PAX

FAIR-ACC

FAIR-SAFETY

ACC-STATUS

ACC-R+D

NUSTAR-SPECTROSCOPY

NUSTAR-EXOTIC-BEAMS

NUSTAR-THEORY

NUSTAR-SHE-PHYS

NUSTAR-SHE-CHEM

NQMA

NQMA-EXPERIMENTS

NQMA-THEORY

INSTRUMENTS-METHODS

AP-EXP-SPECTROSCOPY

AP-EXP-COLLISIONS

AP-METHODS

AP-THEORY

PLPY

PLPY-EXP

PLPY-METHODS

PLPH-THEORY

MATERIALS

PHELIX

BIOPHYSICS

EXTERNAL-HIT

ANNEX-PUBL

ANNEX-COLLABORATIONS

ANNEX-EVENTS

ANNEX-UNIV

ANNEX-EXPERIMENTS

ANNEX-ORGANIGRAM

GSI Scientific Report 2005
GSI Report 2006-1