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S Palestini, G.D. Barr,
A Ceccucci,
J. Cogan,
D. Cundy,
G Fischer,
W Funk,
A Gianoli,
A Gonidec,
G Govi, [......],
C Cerri,
M Cirilli,
F Costantini,
R Fantechi,
S Giudici,
B Gorini,
I Mannelli,
M Sozzi,
C Biino,
I Mikulec
[show abstract]
[hide abstract]
ABSTRACT: The subject of space charge due to positive ions slowly moving in parallel plate ionization chambers is considered. A model for the degradation of the detector response is developed, with particular emphasis on electromagnetic calorimeters.The topics discussed include: (a) the stationary; (b) the time dependent cases; (c) the limit of very large space charge; (d) the electric field dependence of the electron drift velocity; (e) the e#ect of longitudinal development of showers; (f ) the behaviour of the average reductions of response; and (g) the non-uniformity of response for di#erent positions of the shower axis inside the cell defined by the electrodes. The NA48 calorimeter is used as application and for comparison of results. # 1999 Elsevier Science B.V. All rights reserved. PACS: 29.40.Cs; 29.40.Vj; 61.25.Bi Keywords: Ionization detectors; Space charge; Liquid noble gases; Ion mobility; Electromagnetic calorimeters *Corresponding author. E-mail: sandro.palestini@cern.ch. # Permanent address: Dipartimento di Fisica dell'Universita e Sezione dell'INFN di Torino, 10125 Torino, Italy. # Present address: CEA-Saclay-DSM---DAPNIA, 91191 Gif-sur-Yvette, France. # Permanent address: Dipartimento di Fisica dell'Universita e Sezione dell'INFN di Bologna, 40126 Bologna, Italy. # Permanent address: Departamento de F sica, Universidad de los Andes, Me rida 5101-A, Venezuela. 0168-9002/99/$ --- see front matter # 1999 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 8 - 9 0 0 2 ( 9 8 ) 0 1 1 9 3 - 0 1.
02/1999;
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Na Experiment Fischer,
C. Avanzini, G.D. Barr,
P. Calafiura,
M Cirilli,
F Costantini,
D. Cundy,
H Dibon,
F Formenti,
B Gorini, [......],
G M Pierazzini,
M. Porcu,
D Rizzi,
F Rossi,
M Sozzi,
A Taurok,
R. Tripiccione,
M Velasco,
O. Vossnack,
H Wahl
[show abstract]
[hide abstract]
ABSTRACT: The "neutral" trigger system for the selection of K#P2##P4# decays of the NA48 CP-violation experiment is described. The trigger system has been implemented in a 40 MHz "dead-time free" pipeline to allow large rate reduction and high-trigger e#ciency. The trigger decision is based on the information from 13 340 cells of the electro-magnetic calorimeter. Every 25 ns the energy, the centre of gravity, the kaon lifetime and the number of peaks in calorimeter projections are calculated in the trigger. The pipeline system is described and the performance of the trigger during the 1997 data-taking period is discussed. # 1998 Published by Elsevier Science B.V. All rights reserved. *Corresponding author. E-mail: gunther.fischer@cern.ch. # The NA48 Collaboration is: Cagliari, Cambridge, CERN, Dubna, Edinbourgh, Ferrara, Firenze, Mainz, Orsay, Perugia, Pisa, Saclay, Siegen, Torino, Vienna, Warsaw. # On leave from Institute of Nuclear Physics, Cracow, Poland. 1.
02/1999;
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B. Gorini,
C. Avanzini, G.D. Barr,
P. Calafiura,
M. Cirilli,
F. Costantini,
D. Cundy,
H. Dibon,
G. Fischer,
F. Formenti, [......],
M. Porcu,
D. Rizzi,
F. Rossi,
M. Sozzi,
A. Taurok,
R. Tripiccione,
M. Velasco,
O. Vossnack,
H. Wahl,
M. Ziolkowski
[show abstract]
[hide abstract]
ABSTRACT: A first level trigger system based on a 40 MHz digital pipeline
has been developed for the CERN NA48 experiment, aiming at measuring CP
violation in K<sup>0</sup>→2π decays. The outputs of the 13340
cells of the 10 m<sup>3</sup> liquid krypton calorimeter are summed into
64 X and 64 Y projection strips and continuously digitised with 40 MHz
FADCs. This information is used to reconstruct at each clock cycle and
for the two calorimeter projections, the number of clusters, the impact
time of each of them (with a precision of about 3 ns), their total
energy and the first and second moments of the energy distribution.
Based on the quantities listed above, a programmable look-up table
system subsequently computes online the longitudinal position of the
kaon decay vertex and performs an event selection. The system is
described
IEEE Transactions on Nuclear Science 09/1998; · 1.45 Impact Factor
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G.D. Barr,
C. Bruschini,
G Bocquet,
P. Buchholz,
D. Cundy,
N Doble,
W Funk,
L Gatignon,
A Gonidec,
B. Hallgren, [......],
A Givernaud,
L Gosset,
J Heitzmann,
E Mazzucato,
B Peyaud,
R Turlay,
C Biino,
A Ceccucci,
P Maas,
S Palestini
[show abstract]
[hide abstract]
ABSTRACT: The NA48 collaboration is preparing a new experiment at CERN aiming to study CP violation in the K #K system with an accuracy of 2 10 #4 in the parameter 0 ###. Decays into two # #s will be recorded by a quasi#homogeneous liquid krypton calorimeter. A liquid krypton calorimeter has been chosen to combine good energy# position and time resolution with precise charge calibration and long#term stability. The prototype calorime# ter incorporating the #nal design of the electrode read#out structure is presented in this paper. An energy resolution of 3#5# p E with a constant term smaller than 0#5# has been obtained. The time resolution was found to be better than 300 ps above 15 GeV.
07/1998;
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[show abstract]
[hide abstract]
ABSTRACT: We describe a general purpose 40 MHz pipelined trigger processing
board containing six look-up tables and the logic needed to programmably
route the signals between them. A series of identical boards are
connected in cascade in the NA48 CP-violation experiment at CERN, accept
digital inputs generated from calorimeter signals and are used to
perform the different computations necessary for the trigger
reconstruction. The board architecture is designed to be flexible so
that a single basic hardware design can perform all the different
algorithms we require and so that the trigger algorithms can be adapted
if needed. The computation latency of the combined network of eight
boards is approximately 3 μs. We present examples of some of the
functions which have been implemented. We discuss the automatic
reprogramming software which has been developed so that a new design can
be implemented easily
IEEE Transactions on Nuclear Science 07/1996; · 1.45 Impact Factor
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B. Hallgren,
F. Bal, G.D. Barr,
P. Buchholz,
F. Formenti,
W. Funk,
Yu. Kozhevnikov,
A. Lacourt,
G. Laverriere,
M. Martini,
A. Papi,
P. Ponting,
M. Sozzi,
O. Vossnack,
H. Wahl
[show abstract]
[hide abstract]
ABSTRACT: This paper describes the issues encountered in the design of a
large dynamic range digitizer for calorimetry. A gain switching
technology developed for the liquid krypton calorimeter of the NA48
CP-violation experiment at CERN is described in detail. 14 bit dynamic
range and better than 300 ps time resolution were achieved in beam tests
with an 8 channel prototype. A mixed analog/digital ASIC has been
developed. A 13,500 channel system is being produced which will be put
into operation in 1996
IEEE Transactions on Nuclear Science 07/1996; · 1.45 Impact Factor
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G.D. Barr,
C. Bruschini,
C. Bocquet,
P. Buchholz,
D. Cundy,
N. Doble,
W. Funk,
L. Gatignon,
A. Gonidec,
B. Hallgren, [......],
A. Givernaud,
L. Gosset,
J. Heitzmann,
E. Mazzucato,
B. Peyaud,
R. Turlay,
C. Biino,
A. Ceccucci,
P. Maas,
S. Palestini
[show abstract]
[hide abstract]
ABSTRACT: The NA48 collaboration is preparing a new experiment at CERN aiming to study CP violation in the K0- system with an accuracy of 2 × 10−4 in the parameter e(ϵ′/ϵ). Decays in two π0's will be recorded by a quasi-homogeneous liquid krypton calorimeter. A liquid krypton calorimeter has been chosen to combine good energy, position and time resolution with precise charge calibration and long-term stability. The prototype calorimeter incorporating the final design of the electrode read-out structure is presented in this paper. An energy resolution of with a constant term smaller than 0.5% has been obtained. The time resolution was found to be better than 300 ps above 15 GeV.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment.
