Time Projection Chamber for the R 3 B set-up Combination of detectors upstream (target) & downstream...

Time Projection Chamberfor the R3B set-up

Combination of detectors upstream (target) & downstream of the magnet Improvement of A, Z & E* balances

Spallation, fragmentation Identification (γ) of the decaying systems Study of the Coulomb fission of radioactive actinides

TPC: a multi-purpose detectorR3B: a versatile set-up for different physics

superconducting magnet R3B -

GLAD

RPC

Marie-Delphine SALSAC - DSM/IRFU/Service de Physique Nucléaire

GSI Large Acceptance Dipole

Active shielding (B(target) ~ 20 mT) Field integral ~ 4,8 Tm Central field ~ 2,5 T Coil current density ~ 77 A/mm2 Indirect He cooling at 4.2 K with thermo siphon Quench protection with external discharges


04/19/23 Jean-Eric Ducret, DSM/IRFU/Service de Physique Nucleaire 3

The R3B-TPC

TPC sampling schemePC: Proportional counters(high gas amplification) small-Z fragmentsIC: ionisation chambers(low gas amplification) large-Z nuclei

MicroMegas cover of 2x5m²

TPC electrostatics(vertical plane)

9 rows of pads (1 X 10 cm2)~ 6000 channels


04/19/23 Jean-Eric Ducret, DSM/IRFU/Service de Physique Nucleaire 4

TPC active volume

~ 3.2 m~ 1.2 m

~ 0

.9 m


~ 2.5 m

Signal size & processing of the R3B – TPC Signal dynamics & size From Z = 1 to Z = 92, i.e. 104 dynamics Rise time of the primary signals: ~ 5 to 30 ns depending on the drift length Geometrical width of the signals: up to a few mm Rate/channel: 1 - 10 kHz No constraints concerning space and temperature Pads: 10 x 100 mm 3 pads in each row per track Charge deposited for p: 2500 e x GAIN, scaling with Z2

Read-out for the R3B-TPC - 1

45cm

Gas – Tension ..: not definedPressure: 1 barE


Signal size & processing of the R3B – TPC Signal processing 12-bit ADC for Z determination (in the two-gas amplification scheme) 10 significant bits, 1/210 resolution Horizontal coordinate by charge division Vertical coordinate by drift time measurement Horizontal position resolution: x ~ 200 µm, for Z = 1 & 2, x ~ 100 µm, for larger Z Threshold subtraction before data buffering & DACQ, to reduce the data flow Drift time measurement Beam start as t0, pad time as stop

Read-out for the R3B-TPC -2


Signal size & processing of the R3B – TPC

Detector simulation Rather sensitive to the noise in the read-out channels (to keep low with respect to the proton signals) Rather insensitive to cross talk in between read-out channels

Read-out for the R3B-TPC - 3


Time Projection Chamber for the R 3 B set-up Combination of detectors upstream (target) & downstream...

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