progress with the tpc gas monitor dariusz antończyk outline : motivation simulations measurements...
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Progress with the TPC gas monitor
Dariusz Antończyk
Outline :
Motivation Simulations Measurements Summary & Outlook
Motivation We wish to monitor gas quality with high precision GOOFIE is a classical solution (NA49 TPC, CERES TPC,
HADES MDC, STAR FTPC)
We have a three component gas mixture (Ne:CO2:N2)
Modifications
Aim Drift field 400 V/cm Resolution 0.1 ‰ Measurement of
drift velocity and gain
ALICE TPC Collaboration Meeting, Cagliari 16-17.05.2004 Progress with the TPC gas monitor Dariusz Antończyk
Drift monitor detector
Progress with the TPC gas monitor Dariusz Antończyk
Proportional counter modification
Connected to voltage of field cage Added a wire mesh in front of
the window Removed many insulators
-9.86 kV
241Am
Far signal
AK
We have three GOOFIEs from MPI München (Dr. V. Eckardt)
Progress with the TPC gas monitor Dariusz Antończyk
Drift monitor detector
We replaced the HV cable and added copper rings
Simulation of field cage
ALICE TPC Collaboration Meeting, Cagliari 16-17.05.2004 Progress with the TPC gas monitor Dariusz Antończyk
E [
V/c
m]
E [
V/c
m]
Simulation of field cage
ALICE TPC Collaboration Meeting, Cagliari 16-17.05.2004 Progress with the TPC gas monitor Dariusz Antończyk
old new
ALICE TPC Collaboration Meeting, Cagliari 16-17.05.2004 Progress with the TPC gas monitor Dariusz Antończyk
Simulation of Pickup detector newold
ALICE TPC Collaboration Meeting, Cagliari 16-17.05.2004 Progress with the TPC gas monitor Dariusz Antończyk
Simulation of Pickup detector
old new
ALICE TPC Collaboration Meeting, Cagliari 16-17.05.2004 Progress with the TPC gas monitor Dariusz Antończyk
Simulation of Pickup detector
newold
ALICE TPC Collaboration Meeting, Cagliari 16-17.05.2004 Progress with the TPC gas monitor Dariusz Antończyk
Pickup detector
Constructed by A.Radu (GSI)
Ternary gas mixture map (simulations)
ALICE TPC Collaboration Meeting, Cagliari 16-17.05.2004 Progress with the TPC gas monitor Dariusz Antończyk
9.0 9.5 10.0 10.5 11.0
4.0
4.5
5.0
5.5
6.0
N2 (
%)
CO2 (%)
2.4502.4792.5082.5382.5672.5962.6252.6542.6832.7132.7422.7712.800
Drift velocity
9.0 9.5 10.0 10.5 11.0
4.0
4.5
5.0
5.5
6.0
N2 (
%)
CO2 (%)
200.0
223.3
246.7
270.0
293.3
316.7
340.0
Gain
Different dependences for [CO2] and [N2]
Bragg Peak study
ALICE TPC Collaboration Meeting, Cagliari 16-17.05.2004 Progress with the TPC gas monitor Dariusz Antończyk
On-line display
Temp. and O2
Pressure
LV
HVHV
Pickup
Vr
Near
Far
Fan-in/Fan-out
Gas outlet
Gas inlet
CA
MA
C co
ntro
ller
Discr.
FAD
C
ADCTrigger
Set-up
ALICE TPC Collaboration Meeting, Cagliari 16-17.05.2004 Progress with the TPC gas monitor Dariusz Antończyk
ALICE TPC Collaboration Meeting, Cagliari 16-17.05.2004 Progress with the TPC gas monitor Dariusz Antończyk
MeasurementLabVIEW display for the GOOFIE On-line Analysis
ALICE TPC Collaboration Meeting, Cagliari 16-17.05.2004 Progress with the TPC gas monitor Dariusz Antończyk
Long term dependence
hours
hours
hours
hours
T/P [K/bar]
P [mbar]
T [oC]
Ve [cm/s]
Blue – corrected Ve
Black – ON-line Ve
Red – OFF-line Ve
ALICE TPC Collaboration Meeting, Cagliari 16-17.05.2004 Progress with the TPC gas monitor Dariusz Antończyk
Correction for T and P
Correction formula :
Vdcorr = Vd – p1(T/P - <T/P>)
T/P [K/bar]
Vd [cm/s]
ALICE TPC Collaboration Meeting, Cagliari 16-17.05.2004 Progress with the TPC gas monitor Dariusz Antończyk
Drift velocity resolution
Mean : 2.5415 0.0002Sigma : 0.0022 0.0002
Resolution: 0.87 ‰
First try!
ALICE TPC Collaboration Meeting, Cagliari 16-17.05.2004 Progress with the TPC gas monitor Dariusz Antończyk
Gain vs time dependence
hours
hours
hours
gain [a.u]
gain [a.u]
gain [a.u]
ALICE TPC Collaboration Meeting, Cagliari 16-17.05.2004 Progress with the TPC gas monitor Dariusz Antończyk
Summary & Outlook
After applied modifications some improvements have been achieved:
more uniform response of the system 400 V/cm electric field 0.87 ‰ resolution of the GOOFIE drift velocity
In the nearest future further effort will be made to refine the GOOFIE resolution. This can be done by :
improved temperature measurement improved gain measurement
use final electronics (Luciano) and implementthe system into the DCS
ALICE TPC Collaboration Meeting, Cagliari 16-17.05.2004 Progress with the TPC gas monitor Dariusz Antończyk
Summary & Outlook
Problems to be solved :
understanding of gain dependence on various parameters (P, T, gas composition, etc.) small discharges elimination
ALICE TPC Collaboration Meeting, Cagliari 16-17.05.2004 Progress with the TPC gas monitor Dariusz Antończyk
Backup
Simulation of drift velocity
ALICE TPC Collaboration Meeting, Cagliari 16-17.05.2004 Progress with the TPC gas monitor Dariusz Antończyk
Bragg Peak study
ALICE TPC Collaboration Meeting, Cagliari 16-17.05.2004 Progress with the TPC gas monitor Dariusz Antończyk
Fit functions
ALICE TPC Collaboration Meeting, Cagliari 16-17.05.2004 Progress with the TPC gas monitor Dariusz Antończyk
OFF- line y=p0+p1*exp(-exp(-z) – z +1)
z=x-p2/p3
ON- line
gauss fit