used for Real Time Radiation Monitoring of Operation, Assembly, and Quality Control Testing of 10cm × 10cm GEM Detector to be used for Real Time Radiation Monitoring of High Altitude Aircraft and Spacecraft Flights Devon Madden, Zachary Paul, Marcus Hohlmann, Ondrej Doule Florida Institute of Technology Florida Academy of Sciences March 8, 2019

Space Tourism and Transportation Blue Origin New Shepard [5]. SpaceX Crew Dragon 2 [9]. Introduction talk about the future, how non professional astronauts can go to space in the near future Virgin Galactic VSS Unity: Dec. 13, 2018 reached 82.7 km during rocket power test flight Intended to take customer passengers to suborbital space After a few more rocket tests and analysis of flight data, plan for commercial flights in 2019 Blue Origin New Shepard: Jan. 23, 2019 took 8 NASA research and technology projects to space Reached over an altitude of 100 km Plan to send people to space in 2020 Falcon 9 and Crew Dragon Capsule: SpaceX Starship: future project for satellites, ISS missions, interplanetary travel, and earth to earth transport Intended to hold 100 passengers and travel outside earth’s atmosphere Virgin Galactic VSS Unity [18].

Cosmic Radiation Diagram for layers of Earth’s atmosphere [16]. Most of these commercial flights will be reaching the thermosphere Protection of passengers in high altitude air or spacecraft Cosmic radiation and effects from exposure [ ] NASA Radiation Dosimetry Experiment (RaD-X) [ ] Diagram for layers of Earth’s atmosphere [16]. Diagram of Cosmic Ray Air Shower [14].

Application of GEM Detector High altitude aircraft (15 km) Suborbital vehicle (80 km) Directional radiation monitoring Response to incoming radiation Reduce ionizing radiation exposure F104-B Starfighter [8]. Need to emphasize the purpose: - Where is this detector being used? - Why is it being used? - What will it do to make space/airline flights safer? Blue Origin New Shepard [5].

GEM Detector Fundamentals Originally CERN based project for particle physics Detection works through the use of electron avalanching Each foil has tiny holes within them spread throughout the whole foil (Holes are about 70 microns) When a voltage is applied a large electric field is created within each hole If an electron were to drift through one of the holes an avalanche of electrons would form Additional foils are added to amplify the gain that much more (Anywhere between 100-1000 electrons in avalanche, Going as high at 10^6) This high number of electrons creates a current large enough to be detected by the electronics Once they have passed through all the foils a thin wire then picks up the electrons and channels them toward the readout Cross sectional view of foil arrangement inside detector for a triple GEM foil detector [7]. Cross sectional view of holes inside GEM foils [7].

GEM Detector Fundamentals Originally CERN based project for particle physics Detection works through the use of electron avalanching Ionizing Particle The muon passes through ionizing particles (the drift foil recollects the ionized particles) Each foil has tiny holes within them spread throughout the whole foil (Holes are about 70 microns) When a voltage is applied a large electric field is created within each hole If an electron were to fall through one of the holes an avalanche of electrons would form Additional foils are added to amplify the gain that much more (Anywhere between 100-1000 electrons in avalanche, Going as high at 10^6) This high number of electrons creates a current large enough to be detected by the electronics Once they have passed through all the foils a thin wire then picks up the electrons and channels them toward the readout Cross sectional view of foil arrangement inside detector for a triple GEM foil detector [7]. Cross sectional view of holes inside GEM foils [7].

Construction Flowchart 3 foils placed below a drift foil with a spacing of 3-2-2-2 millimeters Foils soldered to the active region Foils are set in a casing that is tightened with metal bolts until airtight, all other areas not secured by screws are sealed with a polymer Active region is then soldered to an High Voltage (HV) board Capacitors & Resistors (RC-circuits) are added to reduce noise created by board Divider is added to split potential across the foils High Voltage board and Electronics Foil Stacking Sealing Detector

Quality Control (QC) Testing QC 2: GEM Foil Test QC 3: Gas/ Pressure Test QC 4: High Voltage (HV) Test QC 5: (To be conducted) Effective Gain Measurement Test Gain Uniformity Test

QC2: GEM Foil Test QC2 results for GEM foil 1 of the 10 x 10 detector. Purpose: Ensure the detector is functioning correctly and at the best performance (QC testing) Based on testing for Short GE1/1 detector documentation QC 1 is done for us, so we skip to QC 2 (If asked: QC 1: is measuring the frame uniformity and depth which is done by the manufacturer) NOTE: you do this for each foil To ensure gem foils aren’t damaged Fast Test (duration: 10 minutes): Measure Impedance (Z), Voltage (V), Spark Count Calculate the Leakage Current using Z and V If Z > 10 GΩ and rate < 2 Hz, foil passes test [2] Purpose: to make sure no damage to gem foils during transport (QC testing) We want a high impedence so the current is lower, we don’t want leakage current because it allows current to exit on unintented conductive paths (Sunpower) Sparking is electrical discharging or the jump of current through a medium (gas) from one point in a circuit to another, if this occurs damage can occur to the detectors components as it operates with a combustible gas (Electrical Discharges) Impedence = the equivalent resistance from the circuit and its elements Multi Mega-Ohmmeter [3].

QC3: Gas/ Pressure Test Purpose: to ensure that the detector is sealed or its leak does not exceed the limit of operation (QC testing) Pressure can not exceed 6 mBar for 10x10 detector we are using (Hohlmann) To ensure detector is pressure sealed Collect pressure data using Data Acquisition and Excel Pressure drop is less than 1 mbar/ hr to pass test [2] by QC documentation, however its ok if pressure drop rate is larger because gas is constantly being supplied during qc4 and qc5 testing Pressure drop is larger because of cheap O-ring. Pressure, temperature, and atmospheric pressure over time for 10 x 10 GEM detector.

HV Divider 5.5 MΩ HV Divider. Circuit diagram of HV board. High Voltage 2.2 nF 100 kΩ 2.2 nF 100 kΩ 100 kΩ 100 kΩ Drift 100 kΩ GEM1T GEM1B 100 kΩ GEM2T GEM2B GEM3T GEM3B 5.5 MΩ HV Divider. 100 kΩ 0.27 nF 51 kΩ Explain what an HV divider is What is it used for and how does it relate to qc4 Include a circuit diagram 1MΩ 1MΩ 1MΩ 1MΩ Pre Amp 550kΩ 500kΩ 450kΩ Circuit diagram of HV board.

QC4: HV Test 10 x 10 detector set up for QC4. Purpose: determine possible malfunctions and defects in HV circuit and spurious signals (QC testing) Determine malfunctions and defects in HV circuit Cover and ground detector and circuit elements Record event count, monitored current and voltage Plot is an example, once again our detector did not pass this test. 10 x 10 detector set up for QC4. IV curve and rate vs. current curve for 10 x 10 GEM detector.

Future Works: QC5 Testing Distinguish cosmic events Conformal coating Effective gain test Response uniformity Purpose: to ensure that we are seeing cosmic events from radiation source (QC testing) Ensure cosmic events are recorded by detector Ensure current is amplified between drift gap to amplifier With and without source (between 570µA to 730µA [2]) Gain is the increase in current from the drift gap to current after amplification (QC testing) Calculate the difference of event counts to determine the number of cosmic events and its rate (QC testing) Calculate the difference of current to determine the effective gain at different currents (QC testing) Range of current is the safe operation without damage to the foils (Hohlmann) Measuring Current: Using QC5 Keithley 6487 control software Get an average current from detector (200 entries) Gain = |( I amp - I gap)/(rate*q electron*N) | Oscilloscope trace from bottom of GEM foil 3 and readout strips.

Thank You Questions? See more at our website: https://research.fit.edu/hep/hohlmann-research-group/

References [1] Abbas, M., Bianco, M., Gola, M., Merlin, J. A., De Oliveira, R., & Shah, A. (2017). Technical Assembly Manual for GE1/1 Chambers. CERN, 1-58. Retrieved February 16, 2019. [2] Airplanes of the Past: F-104 Starfighter. (n.d.). Retrieved March 4, 2019. [3] Arends, S. (2018, June 17). [Insulation Tester 244 MEGGER MIT485 by RECOM Electronic AG]. Retrieved February 17, 2019. [4] Bianco, M., Dorney, B., & Merlin, J. A. (2016). GE1/1 Quality Control : Instructions. CMS GEM INTERNAL NOTE, 1-52. Retrieved February 16, 2019. [5] Blue Origin. (2019, January 8). [New Shepard Rocket at Liftoff]. Retrieved March 1, 2019. [6] Calvert, J. B. (2002, November 3). Electrical Discharges. Retrieved February 16, 2019. [7] CERN Gas Detectors Development: Gas Electron Multiplier. (n.d.). Retrieved February 18, 2019. [8] Conner, M. (2017, August 7). [F-104B #819 NASA]. Retrieved February 28, 2019. [9] Dean, J. (2019, March 03). SpaceX Crew Dragon docks safely at ISS on Demo-1 test flight. Retrieved March 4, 2019. [10] Dunbar, B. (2011, February 14). Higher Altitude Improves Station's Fuel Economy. Retrieved March 4, 2019.

References (Continued) [11] Foust, J. (2018, December 14). Branson looks ahead to beginning commercial SpaceShipTwo flights. Retrieved March 4, 2019. [12] Garner, R. (2017, January 25). NASA Studies Cosmic Radiation to Protect High-Altitude Travelers. Retrieved February 16, 2019. [13] Gonzalez, O. (2018, April 28). What is a Suborbital Flight? How SpaceX and Blue Origin's Launches Differ. Retrieved March 4, 2019. [14] HAWC: Cosmic Rays. (2011). Retrieved March 4, 2019. [15] Hocurscak, L. (2018). Health risks of cosmic rays. University of Ljubljana, 1-10. Retrieved February 17, 2019. [16] Russell, R. (2015). Layers of the atmosphere: Troposphere, stratosphere, mesosphere and thermosphere [Digital image]. Retrieved February 28, 2019. [17] Sheetz, M. (2019, January 23). Blue Origin successfully launches experiments for NASA as Bezos' company nears first human flights. Retrieved March 4, 2019. [18] Virgin Galactic. (2018, December 13). [VSS Unity]. Retrieved February 28, 2019. [19] What is conformal coating? (n.d.). Retrieved March 4, 2019. [20] What is Leakage Current? (2014, July 1). Retrieved February 16, 2019.