The nuclear equation of state (EOS) is probed from statistical parameters, determined in an excitation function experiment on p+Xenat reactions at 200–1400 MeV. Total charge (Z) distributions follow ...a cascade–multifragmentation–evaporation (CFEM) model well. The caloric curve in regions supposedly dominated by fast processes is compatible with a pure statistical multifragmentation (SMM) process, where the temperature (T)–excitation energy (ϵ*) relation starts in the Fermi liquid phase and progresses into a liquid/gas coexistence region, where it remains up to 1400 MeV. A local peak in T at ϵ*=2.1 MeV agrees with the idea of sudden fragmentation.
We describe the detectors for identification of charged particles and fragments in CHICSi, a large solid angle multi-telescope system mounted inside an ultra-high vacuum (UHV), cluster-jet target ...chamber. CHICSi performs nuclear reaction experiments at storage rings. The telescopes consist of a first very thin, 10–
14
μm
Si detector, a second
300
μm
(or possibly
500
μm
) ion implanted Si detector supplemented by a
6
mm
GSO(Ce) scintillator read out by a photodiode (PD) or by a third
300
μm
Si detector. The telescopes provide full charge separation up to
Z=17 and mass resolution up to
A=9 in the energy range 0.7–
60A
MeV
. The thin p-i-n diode detector, etched out from a
280
μm
Si wafer, and the GSO/PD detector, both exclusively developed for CHICSi, provide an energy resolution ⩽8%, while the standard
300
μm
detectors have ⩽2% energy resolution. Radiation stability of the Si detectors is confirmed up to an integrated flux of 10
10 alpha particles. The GSO detector has 70% light collection efficiency with the optical coupling to the PD a simple open,
0.2
mm
, gap. A new method, developed to perform absolute energy calibration for the GSO/PD detector is presented.
CELSIUS Heavy-Ion Collision Silicon detector system (CHICSi) is a large solid angle, barrel-shaped detector system, housing up to 600 detector telescopes arranged in rotational symmetry around the ...beam axis. CHICSi measures charged particles and fragments from nuclear reactions. It operates at internal targets of storage rings. In order to optimize space and momentum-space coverage and minimize the low-energy detection limits, CHICSi is designed for use in ultra-high vacuum (UHV, ∼10
−8
Pa) inside a cluster-jet target chamber. This calls for materials in mechanical support, detectors, Very Large Scale Integrated (VLSI) electronics, connectors, cables and other signal transport devices with very low outgassing. Two auxiliary detector systems, which will operate in coincidence with CHICSi, a heavy-recoil, time-of-flight system (HR-TOF) also placed inside the target chamber and a projectile fragmentation wall (PF-WALL) located outside the chamber, have also been constructed. In total, this combined system registers more than 80% of all charged particles and fragments from typical heavy-ion reactions at energies of a few hundreds of MeV per nucleon.
(CHICSi) Celsius Heavy Ion Collaboration Si detector system is a high granularity, modular detector telescope array for operation around the cluster-jet target/circulating beam intersection of the ...CELSIUS storage ring at the The. Svedberg Laboratory in Uppsala, Sweden. It is able to provide identity and momentum vector of up to 100 charged particles and fragments from proton–nucleus and nucleus–nucleus collisions at intermediate energies, 50–
1000
A
MeV
. All detector telescopes as well as the major part of electronic readout system are placed inside the target chamber in ultra-high vacuum (UHV, 10
−9–
10
−7
Pa
). This requires Very Large Scale Integrated (VLSI) microchip for the spectroscopic signal processing and the generation and transport of digital control signals. Eighteen telescopes, read out with chip-on-board technique by ceramics Mother Boards (MB) and corresponding 18 microchips are mounted on a
450×45
mm
2
Grand Mother Board (GMB), processed on FR4 glass-fibre material. Each of these
28
GMB
units contains a daisy-chain organisation of the VLSI chips and associated protection circuits. Analogue-to-digital conversion of the spectroscopic signals is performed on a board outside the chamber which is connected on one side to a power distribution board, directly attached to a UHV mounting flange, and on the other side to the VME-based data acquisition system (CHICSiDAQ). This in its turn is connected via a fibre-optic link to the general TSL acquisition system (SVEDAQ), and in this way data from auxiliary detector systems, read out in CAMAC mode, can be stored in coincidence with CHICSi data.
Dynamical and statistical fragment emission processes in 200 A MeV Ne-20 + Ar-40 collisions are well probed by measurements of charge (Z), mass (A) and momentum vector ((p) over right arrow) of all ...fragments in large parts of the available momentum space. We present such data obtained at the cluster-jet target of the CELSIUS storage ring, for the first time with an internal, ultra-high vacuum (UHV) compatible detector system (CHICSi). Energy and angular dependence in Z and A distributions are not reproduced by a single-step model, e.g., those based on molecular dynamics (MD), but require a complete three-step model. We use here the intranuclear cascade+ statistical multifragmentation + secondary evaporation model (CFEM). The angular dependence of isobaric ratios, like He-6/Li-6 at low emission velocities and temperatures extracted from isotopic (double) ratios, do exhibit differences, even from this model. These differences, which call for adjustment of model parameters, are discussed. (c) 2005 Elsevier B.V. All rights reserved.
A high precision, time-of-flight hodoscope has been constructed to analyse the secondary pion beam at GSI, Darmstadt. The hodoscope comprises three scintillator planes with the individual ...scintillator rods read out by photomultipliers in both ends. A new active base of the emitter follower type has been developed for stabilization of voltages at the last dynodes of the photomultiplier. The time resolution of this system was found to be σ⩽150ps for counting rates up to 2MHz.
Inclusive H-2(He-3,t) Reaction at 2 GeV Ramstein, B; Mosbacher, CA; Bachelier, D ...
The European physical journal. A, Hadrons and nuclei,
10/1999, Volume:
6
Journal Article
Design of the NORDBALL Data Support System Holm, A.; Hey-Christensen, P.; Jerrestam, Dan ...
IEEE transactions on nuclear science,
1987, Volume:
34, Issue:
4
Journal Article
Peer reviewed
Starting the design of the complete data support system with focus on the data paths has helped in the comprehension of the system. It also naturally divided the continued work into subprojects one ...of which has been the design of the message system presented here. The message system has made it easier for the design group to discuss the structure of the VME based subsystems and the time measurements give us hope that although simple it will be adequate for our purpose. Modula-2 was just the answer to the problem of making systems programing easy and correct.
