1. 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

2. 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].

3. 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].

4. 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].

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 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].

6. 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 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].

7. Construction Flowchart
3 foils placed below a drift foil with a spacing of 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

8. 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

9. 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].

10. 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.

11. 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.

12. 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.

13. 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.

14. Thank You
Questions?
See more at our website:

15. 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, 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, 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.

16. 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, 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.