Transcript GEMandVFAT_small

TRIPLEGEM and VFATs
at
The Test Beam Area
Totem collaboration meeting 7-3-2007
N. Turini……reporter
Eraldo Oliveri main worker!
List of Tests
-Stability Test
The System at the end is stable (after a lot of pain….we removed an antistatic bag covering the DOHM hosting
circuit, and everithing stabilzed!!!!).
The measurements seem to be sufficiently reproducible.
-noise Analysis tools
Threshold Scan.
Pulse Calibration Scan
-VFATs noise Tests
Hybrid V1 shows a different behavior than Hybrid V2.
-High Voltage noise Studies
Non float H.V. in a nearby NIM crate
Floating power supply.
Main noise improvements:
-Very GOOD GND Connection of the Floating Power Supply to the MAIN GND near the detector
-Remove the H.V.-READOUT GND Connection on Detector
-Special GND connection between VFAT and GEM GND plane
-VFATs on GEM Studies
VFATs on strips in RUN mode introduce noise on Pads VFAT. Adding another VFAT on other pads seems to reduce
the noise…to be investigated more accurately.
We need to study at least half equipped detector.
Noise Analysis Tools: Pulse Calibration Scan
Check of the correlation between s-erf function and pads capacitance to understand if the
sigma of the erf fit is a good description of the noise
VFAT C2F2
Noise Analysis Tools: Pulse Calibration Scan
Noise vs Channels:
VFAT C2F2 connected to Detector
(with special GND connection).
The value of the noise for the smallest
PAD. That is~ 5.335
If we correlate the noise with the area of the pad we can do a linear fits. In first approximation the intercept
could be associated to the “offset” noise due to the VFAT and to the connection on the readout foil.
Fitting only on the large area pads, because large pad noise are less sensitive to readout foil noise, we get
~4.2 Count Units for Area=0.
VFAT C2F2 not connected to Detector
Noise Analysis Tools: Pulse Calibration Scan vs Threshold Scan
Comparison between the data
taken with threshold scan (MEAN
Y and RMS Y at 5% and 1%) and
the sigma of the erf Fit of the
pulse calibration scan curve.
A measure of the MEAN Y and
RMS Y of all channel output of
the threshold scan, reflects the
behavior of the single channel
pulse calibration scan.
Noise Measurements vs Run #….….
C2F2(Pads PS12) ON
FAF3(Internal Strips) ON
B0F2(External Strips) ON
C272(Pads PS13)
C2F2(Pads PS12) ON
FAF3(Internal Strips) ON
B0F2(External Strips) ON
NO HV
HV GROUNDED
C2F2(Pads PS12) ON
& FAF3(Internal Strips) ON
C2F2(Pads PS12) ON
HV-READOUT
GND connection
NO YES NO
Special GND
Connection on
C2F2
YES NO YES
VFATs
STUDIES
HV FLOAT
NO HV
Reduction of
noise with a
better GND
connection of
the HV Power
Supply near the
detector
HV-READOUT
GND
connection
removed on the
detector
OFF
4kV
HV FILTER
removed
GND from Control Room
Through Trigger Line
Some Initial GND Loop
LV Power Supply
VFAT SPECIAL GND
CONNECTION
H.V.-READOUT GND
CONNECTION
Floating
H.V.
VFAT
HV
Filter
Contact
between filter
box and table
Cable to
connect the
H.V. Cable
shield to the
Table
TABLE
Control Room
TEST BEAM ZONE
MAIN GND
H.V. GND Improvement
C2F2 with FAF3 in Sleep Mode HV
FLOATING CONNECTED + Standard CAEN
Small Filter and TURNED ON to 10V
C2F2 with FAF3 in Sleep Mode HV
FLOATING CONNECTED + Standard CAEN
Small Filter and TURNED ON to 10V and the
shv shield in contact with the GND of of
the table
WITH A CABLE
C2F2 with FAF3 in Sleep Mode HV FLOATING
CONNECTED + Standard CAEN Small Filter
and TURNED ON to 10V and the shv shield
in contact with the GND of of the table
WITH A SHORT CABLE
C2F2 with FAF3 in Sleep Mode HV
FLOATING CONNECTED + Standard CAEN
Small Filter and TURNED ON to 10V and the
shv shield in contact with the GND of of
the table
WITH A BIGGER CABLE
C2F2 with FAF3 in Sleep Mode HV FLOATING
CONNECTED + Standard CAEN Small Filter
and TURNED ON to 10V and
WITH THE FILTER BOX (gnd of H.V.) IN
CONTACT WITH THE GND OF THE TABLE
For the future….
-Hardware System
Fix the Clock signal
Fix trigger ground
-Software tools
Most of the useful plots and macros are implemented, need some more automatic scan
macros.
-noise Test
Change of the Low Voltage Power Supply Cable. (And eventually test a local one).
Study an half-equipped or totally–equipped TOTEM TripleGEM.
Study of the definitive H.V. Power Supply.
Check if we need others GND pin on the transition board near the device connectors to
have a better GND connection with the VFAT with an additive GND cable between VFAT
and transition board.
TIME RESOLUTION OF THE TRIGGER SYGNALS and more……
-Hardware
Read out of the trigger bits
Put one trigger bit on a connector for time comparison with external trigger
-Software
Check single channel threshold setup before the test beam!
The END