1. Anomalies &/or differences with the configuration Explanations, analyzes, impacts Updates EUSO-BALLOON, Flight review 04/06/2014 Guillaume Prévôt (APC) EUSO-balloon: changes in the baseline configuration

2. 2 LVPS-CPU EUSO-BALLOON Flight review, June the 4 th 2014 - CNES Discovered in Naples in July 2013 Unability to power the CPU because of spikes of current happening at the boot of the CPU Change of the converters Implementation of a cooling plate connected to the DP backplate to dissipate the overheat New board delivred in September 2013, working properly, successfull stress tests Tested at 3mbar between [-20°C to 50°C] and inside the whole system at 3mbar between [0°C to 50°C] Change of design on the LVPS board was transparent for the rest of the subsystems except the PWP, but the extra- power was taken into account and inside the margins.

3. 3 LVPS-PDM Discovered in Paris in January 2014 Unability to power the PDM board + the 6 ASIC boards Change of converters (15W -> 20W) Change of the wires (drop of voltage) Implementation of a cooling plate connected to the DP backplate to dissipate the overheat Working properly Tested inside the whole system at 3mbar between [0°C to 50°C] Change of design on the LVPS board was transparent for the rest of the subsystems except the PWP, but the extra-power was taken into account and inside the margins.

4. 4 Central screws of the 9 EC_Units Discovered in Paris in June 2013 The fixation screw in brass of the EC-unit is extremely close to 4 cut pins of MAPMTs which are connected to the cathode. Up to 200V, the resistance is > 20 Gohms, so OK, but at the minimum operating voltage (-900 V), there are "sparks" which can be observed as very big pulses on all anodes, and a cathode current of a few µA (instead of fA) Insulation of the mechanics of the PDM: delrin instead of aluminum top frame Make a contact to the EC-Unit central screw of the cathode voltage (insulating this central screw) EUSO-BALLOON Flight review, June the 4 th 2014 - CNES

5. 5 Spiders Discovered in Toulouse, in November 2013, measured in January 2014 Bad contact between the spiders and the lenses, measured and characterized (read report) Production and gluing of the new spiders New characterization, found OK Increase of the mass taking into account (69% of margins in the screws resistance) EUSO-BALLOON Flight review, June the 4 th 2014 - CNES

6. 6 L2 diffractive Fresnel lens Discovered in Riken (Japan), in October 2013, fully characterized in April 2014 in Toulouse The second lens of the optical system (called “L2” or “diffractive lens”) has twice less converging power than required by the design of the optical system (because of a mistake in the parameters given to the manufacturing machine) Size of the PSF ~ twice bigger with the L2 lens Efficiency divided by a ~ factor of two New baseline: 2-lens configuration (“TA-euso” configuration) : Front lens and rear lens from first design. Middle lens removed Impact in the design: field of view (±4° instead of ±6° still representative of JEM-EUSO), focal distance (move of the PDM from 382 to 431mm to the rear lens position), update of the ICD)

7. 7 HVPS location in the PDM In March 2014, we burned the HVPS because the 28V and the 5V pins were too closed The integration of the 2 boxes (between the ASIC boards) had been very complicated, we decided to integrate the boxes outside the PDM We used the opportunity to do a few modifications, especially on the inter- connection between boxes (replacing nude wires by connectors) and course in spacing the 28V & 5V pins out We designed the new boards after studies, tested and integrated them successfully We shifted the hatch We updated the interface document (ICD)