Triple GEM Beam Test within PHENIX DC Upgrades Meeting 4/14/04 B. Azmoun PHENIX Brookhaven National Lab
Jan 17, 2018
Triple GEM Beam Test within PHENIX
DC Upgrades Meeting 4/14/04
B. AzmounPHENIX
Brookhaven National Lab
4/14/04 B. Azmoun 2
Outline
• Basic format of presentation: Timeline of tests performed with triple GEM detector in and out of close proximity to A-A beam in PHENIX.– Simple Survival test (trips, sparks)– Performance Evaluation (Gain, Stability, Response to beam-beam collisions)
• Data acquired with GEM detector mounted in various orientations within central region of PHENIX.– Self Triggered Fe-55 Spectra– Beam-Beam Triggered Data (Correlation between Beam collisions and GEM hits)
• Comparison of: Fe-55 Peak Position, abs. Signal Gain, %Res.(FWHM), and Background:– Lab Vs. PHENIX Data – Beam ON Vs. Beam OFF Data– Magnet (Inner/Cent.) ON Vs. Magnet OFF Data
• Objective:Objective: To monitor the behavior of a triple GEM detector within the PHENIX interaction region, and to compare these results with in-lab tests.
4/14/04 B. Azmoun 3
Layout of Triple GEM DetectorGases Used
• Ar/CO2 (70/30)
> Volt Configuration:DG: 0.5kV/cm
TG1:2.5kV/cm
TG2: 3.0kV/cm
IG: 3.5kV/cm
> Nominal Operating Gain:~6.5x103 @ Foil Pot. = 360V
• CF4
> Volt. Configuration:DG: 0.5kV/cm
TG1:2.5kV/cm
TG2: 3.5kV/cm
IG: 5.0kV/cm
> Nominal Operating Gain:~3.2x103 @ Foil Pot. = 495V
Std. Conical, Segmented
CERN Foils
Active area of pads ~1.0x1.5cm
Photos of detector in place within PHENIX
Det. Mounted near N. Cent. Mag.
Det. on MVD lifting table,Mylar window Facing Upright
4/14/04 B. Azmoun 5
Lab Test Data• Data taken in the lab provides a baseline measurement.
Timeline Start:
Run#: 1 (Lab)Date: 3/2/04Gas: Ar/CO2 (70/30)HV ON: 1:30 pmData Run: 2:50 pmFoil Pot. = 360VGain= 5923 , Res.= 25%BEAM: N/A, ZDC = N/ABeam Cond: N/AMag: N/A
• Gas: Ar/CO2 (70/30)
HV: ON
Data Run Parameters
Fe-55 Spectrum
4/14/04 B. Azmoun 6
GEM Det. Mounted in inner central region of PHENIX
Orientation #1:•Gas: Ar/CO2 (70/30)
Beam: OFF, Mags: OFF HV: ON
Com parison of Gain Curves
10
100
1000
10000
100000
310 320 330 340 350 360 370 380Foil Potential [Volts]
Abs
olut
e G
ain
Lab
Beam Test @PHENIX
Run#: 2Date: 3/3/04Gas: Ar/CO2 (70/30)HV ON: 1:00 pmData Run: 5:20 pmFoil Pot. = 360VGain= 6070 , Res.= 37%BEAM: OFF, ZDC = 0HzBeam Cond: Mag: OFF
Isolation Trans. Mounted onto Det.
Spect. ~ identical to lab data, but inc. peak width
PedestalCalib. Pulse
4/14/04 B. Azmoun 7
Run#: 5Date: 3/4/04Gas: Ar/CO2 (70/30)HV ON: 1:05 pmData Run: 6:25 pmFoil Pot. = 360VGain= 6827 , Res.= 34%BEAM: OFF, ZDC = 0HzBeam Cond: Mag: OFF030404_360_241.txt
Run#: 3Date: 3/4/04Gas: Ar/CO2 (70/30)HV ON: 1:05 pmData Run: 3:35 pmFoil Pot. = 320VGain= 187 , Res.= 56%BEAM: OFF, Au I = 35x109
Beam Cond: Mag: ON030404_320_8p7.txt
Run#: 8Date: 3/17/04Gas: Ar/CO2 (70/30)HV ON: 8:10 amData Run: 9:00 amFoil Pot. = 360VGain= 6176 , Res.= 40%BEAM: OFF, ZDC = 0HzBeam Cond: Mag: OFF
•Variation in position of main peak is within normal limits (<+/-10%)
Beam Dumped
Beam: ON, Mags: ON
~ Consistent Response 13 days later
HV: ON Beam: OFF, Mags: OFF
END of END of Fill #1Fill #1
320 V
(This was the only spectrum measured during fill #1, before the beam dump.)
Survival Test: Passed (GEM exhibits normal behavior near beam)
4/14/04 B. Azmoun 8
Orientation #2:•Gas: Ar/CO2 (70/30)
Run#: 9Date: 3/17/04Gas: Ar/CO2 (70/30)HV ON: 11:25 amData Run: 11:55 amFoil Pot. = 360VGain= 6823 , Res.= 35%BEAM: OFF, ZDC = 0HzBeam Cond: Mag: OFF
HV: ON Beam: OFF, Mags: OFF
Isolation Transformer moved outside of PHENIX field boundaries, to DAQ in
PHENIX rack room for orient. 2, 3, and 4.
Similar Spect. Compared to Orient. #1
4/14/04 B. Azmoun 9
Run#: 10Date: 3/17/04Gas: Ar/CO2 (70/30)HV ON: 11:25 amData Run: 1:45 pmFoil Pot. = 360VGain= 6845 , Res.= 33%BEAM: OFF, ZDC = 0HzBeam Cond: Mag: ON
Run#: 14 (BB trig. Data)Date: 3/18/04Gas: Ar/CO2 (70/30)HV ON: 4:40 amData Run: 7:00 amFoil Pot. = 360VFract. of events above ped. = 4.4%BEAM: ON, ZDC ~2.6kHzBeam Cond: Mag: OFF
•Variation in position of main peak is within normal limits (<+/-10%)Magnets ON do not affect data !
Mags: ON
Run#: 12Date: 3/18/04Gas: Ar/CO2 (70/30)HV ON: 4:40 amData Run: 5:40 amFoil Pot. = 360VGain= 6172 , Res.= 38%BEAM: ON, ZDC = 3.56kHzBeam Cond: Mag: ON
Inc. in backgnd.
Beam: ON, Mags: OFF>>ON HV OFF>>ON
Fill #2Fill #2END of END of Fill #2Fill #2
Fract. of events above ped. (~ch.70) = 4.4%
Beam-Beam Triggered Data
Ped.
4/14/04 B. Azmoun 10
•Gas: Ar/CO2 (70/30), CF4
Orientation #3:
Run#: 15 (BB trig. Data)Date: 3/19/04Gas: Ar/CO2 (70/30)HV ON: 1:00 amData Run: 1:47 amFoil Pot. = 360VFract. of events above ped. = 4.6%BEAM: ON, ZDC = 1.56kHzBeam Cond: Mag: ON
Run#: 16Date: 3/19/04Gas: Ar/CO2 (70/30)HV ON: 1:00 amData Run: 2:13 amFoil Pot. = 360VGain= 5540 , Res.= 43%BEAM: ON, ZDC = 1.47kHzBeam Cond: Mag: ON
Large Inc. in background (as well as Dec. Gain)
4.6%Fill #3Fill #3
Ar/CO2 (70/30)
Beam: ON, Mags: ON
4/14/04 B. Azmoun 11
Switch to CF4
HV OFF>>ONRun#: 17Date: 3/19/04Gas: CF4
HV ON: 5:50 amData Run: 6:41 amFoil Pot. = 495VGain= 3200 , Res.= 79%BEAM: ON, ZDC = 2.48kHzBeam Cond: Mag: ON
Run#: 18 (BB trig. Data)Date: 3/19/04Gas: CF4
HV ON: 5:50 amData Run: 6:51 amFoil Pot. = 495VFract. Of events above ped. = 2.7%BEAM: ON, ZDC = 2.40kHzBeam Cond: Mag: ON
Run#: 19Date: 3/19/04Gas: CF4
HV ON: 5:50 amData Run: 7:08 amFoil Pot. = 495VGain= 3277 , Res.= 83%BEAM: OFF, ZDC = 0HzBeam Cond: Mag: ON
Bkgnd. Persists during CF4 Runs, but is relatively smaller
Smaller Number of Counts compared with Ar/CO2
Dec. in Bckgnd.
Beam: OFF,
Mags: ON
(HV Remains ON)
2.7%
Mags /HV Trip
END of END of Fill #3Fill #3
4/14/04 B. Azmoun 12
Run#: 21 (BB trig. Data)Date: 3/19/04Gas: CF4
HV ON: 7:28 amData Run: 9:05 amFoil Pot. = 495 VFract. of events above ped. = 5.1%BEAM: ON, ZDC = 4.42kHzBeam Cond: Mag: ON
Run#: 22Date: 3/19/04Gas: CF4
HV ON: 7:28 amData Run: 10:24 amFoil Pot. = 495VGain= ? , Res.= ?BEAM: ON, ZDC = 2.77kHzBeam Cond: Mag: ON
(Overflow count rate inc.)Run#: 20Date: 3/19/04Gas: CF4
HV ON: 7:28 amData Run: 7:57 amFoil Pot. = 495VGain= 2758 , Res.= 104%BEAM: OFF, ZDC = 0HzBeam Cond: Mag: ON
Large Inc. in Backgnd.
HV: OFF>>ON
Mags. OFF>>ON (Beam Remains OFF)
Inc. in number of counts above ped.
Beam ON
Peak lost in Backgnd ... Beam related ??
5.1%Fill #4Fill #4
4/14/04 B. Azmoun 13
Run#: 24Date: 3/19/04Gas: CF4
HV ON: 11:40 amData Run: 11:50 amFoil Pot. = 495VGain= 3206 , Res.= 73%BEAM: OFF, ZDC = 0HzBeam Cond: Mag: OFF
•Other than some anomalies (e.g. run 16), possibly related to inc.’d background, the variation in the position of the main peak is within normal limits (< +/-10%).
Run#: 23Date: 3/19/04Gas: CF4
HV ON: 11:40 amData Run: 11:46 amFoil Pot. = 495VGain= 3129 , Res.= 77%BEAM: ON, ZDC = 1.97kHzBeam Cond: Mag: OFF
Peak Recovered after HV OFF/ON, (Mag OFF, Beam still ON)
HV: OFF>>ON Mags: OFF
Dec in Backgnd.
Beam Dumped
END of END of Fill #4Fill #4
4/14/04 B. Azmoun 14
•Gas: CF4
Orientation #4:
Run#: 25Date: 3/19/04Gas: CF4
HV ON: 1:09 pmData Run: 1:12 pmFoil Pot. = 495VGain= 3219 , Res.= 76%BEAM: OFF, ZDC = 0HzBeam Cond: Mag: ON
Similar to Orient. 3, with beam OFF, Mags ON
Beam: OFF, Mags: ON
4/14/04 B. Azmoun 15
Run#: 26Date: 3/19/04Gas: CF4
HV ON: 1:09 pmData Run: 3:24 pmFoil Pot. = 495VGain= 3155 , Res.= 72%BEAM: ON, ZDC = 5.7kHzBeam Cond: Mag: ON
Run#: 27(BB trig. Data)Date: 3/19/04Gas: CF4
HV ON: 1:09 pmData Run: 3:47 pmFoil Pot. = 495VFract. of events above ped. = 0.22%BEAM: ON, ZDC = 5.35kHzBeam Cond: Mag: ON
• Variation in the position of the main peak is within normal limits (< +/-10%).
Lower backgrnd. Compared to Orient. #3
Beam: ON
Dec. in number of counts above ped.
0.22%Fill #5Fill #5END of END of Fill #5Fill #5
4/14/04 B. Azmoun 16
Gain Stability• The following plot depicts the
variation in gain at a constant field potential within Ar/CO2 and CF4 during the series of measurements presented in the previous slides.
Gain Stability of Sm all-CERN triple GEM in different gases, using a ~10Hz Fe-55 Source
0.8
0.9
1
1.1
1.2
1.3
1.4
0:00 0:28 0:57 1:26 1:55 2:24 2:52 3:21
Elapsed Tim e after HV is applied [hr:m in]
Rel
ativ
e ga
in
Ar/CO2 (80/20)
CF4
• Gain variations are mainly due to two factors:
1. Fluctuations in physical parameters like temperature, pressure, etc.
2. Before arriving at a steady state value, the gain initially continues to grow due to a charging effect within the Kapton foil, after the HV is applied (see the example to the right).
Gain Stability @ Const. Gain
0
0.2
0.4
0.6
0.8
1
1.2
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28
Run #
Gai
n N
orm
aliz
ed to
Lar
gest
Val
ue
Ar/CO2 (360V)
CF4 (495V)
Low transient Gain due to charging effect
Large Gain Drop ???
4/14/04 B. Azmoun 17
% Res. Vs. Data Run% Res. (FWHM) Vs. Data Run
0
20
40
60
80
100
120
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28
Run #
% R
es. [
%]
Ar/CO2 (70/30)
CF4
LAB
320 V
RUN #22: Peak Lost in Bckgnd.
4/14/04 B. Azmoun 18
Scaler Rates near PHENIX: 3/19/04
Anomalous Behavior of Det. (Run 21- 22)
4/14/04 B. Azmoun 19
Summary• The GEM detector performed smoothly within the central
region of PHENIX using both Ar/CO2 (70/30) and CF4– trouble free operation at reasonable gains in both gases – no sparking or excessive gain instabilities with beam ON, or during a
beam dump
• No observed effect in detector operation due to magnetic field
• Detector sees low energy, beam related background when positioned close to the beam (primary signal < 100 e’s) – possibly less sensitive with CF4
• The detector appeared to be sensitive to beam conditions– large increase in low energy background seen during one fill with CF4,
but decreased dramatically at other times (so far cannot correlate this with scalers of background counters--see slide #18)