Air Shower Detection Workshop at High Altitudes - Instrument Testing & Results
Explore the testing scheme and primary results of the KM2A PMT detector unit used in air shower detection at high altitudes. The system includes a schematic diagram, control panel details, and linearity measurement using LEDs. Gain insights from the 2nd workshop held in 2011.
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Presentation Transcript
logo KM2A PMT testing platform FENG Cunfeng, LI Chaoju, SUN Yansheng Shandong University THE 2ndWORKSHOP OF AIR SHOWER DETECTION AT HIGH ALTITUDES IHEP, Beijing, 17~19, Feb. 2011
Outline LHAASO KM2A PMT PMT testing scheme and instrument Primary testing results Summary The 2nd workshop of air shower detection at high altitudes 2011/2/18 2
LHAASO KM2A PMT KM2A detector unit: Each detector unit consist of 16 plastic tiles and one PMT. PMT couple to plastic tiles by around 100 optical fibers. Dynamical range: 1~3000 charge particles Total 5,000 units, means 5,000 PMTs Characteristics of PMT for KM2A anode linearity range: ~100mA within 5% spatial uniformity: <10% in the center region of the window TTS(transit time spread): ~1ns Low noise Gain: 106 The 2nd workshop of air shower detection at high altitudes 2011/2/18 3
Schematic diagram of the testing system PC WinXP+Labview Aging box1 VME LED HV Aging box2 SY1527 scale LTD QDC amp Aging box3 15 PMTs Pulse generator fan in/out Oscilloscope Digital motor LED1 Diffusion filter LED2 15 PMTs ps pulse laser dark box The whole system is controlled by the central compute 4
Instrument VME DAQ system HV power supply SY1527 +70 channel output Scanning & testing dark box scan 16 PMTs simultaneously Pulse generator 8 output channels Oscilloscope band width: 500MHz Picosecond pulse laser, LED driver The 2nd workshop of air shower detection at high altitudes 2011/2/18 5
Control panel Developed with LabView Main panel Function panel DAQ(VME control) Pulse generator HV power supply Scan motor Oscilloscope The 2nd workshop of air shower detection at high altitudes 2011/2/18 6
Linearity measurement Two LEDs used: LED1, LED2 LED driver amplitude: 0~20V LED driver width: 20ns LED driver triggered by pulse generator LED1 and 2 light alternately and together linearity=[Iled1+led2-(Iled1+Iled2)]/Iled1+led2*100% The 2nd workshop of air shower detection at high altitudes 2011/2/18 7
Uniformity measurement Optical fiber scan the PMT window in 2D. Step pace:1mm Control by digital motor Central computer communicate with digital motor, LED driver and DAQ system The 2nd workshop of air shower detection at high altitudes 2011/2/18 8
Rise time, TTS Light source : picosecond pulsed light (laser diode) trigger by the generator Width: ~100ps Oscilloscope used to measure the rise time, TTS The measurement results are read to central PC with ethernet . One channel input the trigger . 3 channels for PMTs signal. rise time read from oscilloscope directly TTS(transit time spread): Read the PMT signal and laser trigger signal wave shape Transit time=Tsignal-Ttrigger-Tdelay The 2nd workshop of air shower detection at high altitudes 2011/2/18 9
Gain & Single photoelectron peak qdc/hv XY 1E+8 Gain XP2622 HV: 1400-2200V 1E+7 1E+6 Single photoelectron peak XP2622 HV: 1800V 1300 2200 HV The 2nd workshop of air shower detection at high altitudes 2011/2/18 10
Summary The PMT testing platform almost ready The platform is easy to use One push, all results will automatic present Except the oscilloscope, need switch manually. The platform is speedy One batch 15 PMTs, testing simultaneously One or two batch per day. One year or half year will finish all 5,000 tubes. The 2nd workshop of air shower detection at high altitudes 2011/2/18 11
Thanks for your attention! The 2nd workshop of air shower detection at high altitudes 2011/2/18 12
