- Functional Requirements

- Background

- Examples of expected Signal Track

- An “idea” of angular resolution

E U S O - B A L L O O N D E S I G N R E V I E W, 1 8 . 1 2 . 2 0 1 2 , C N E S T O U L O U S E

Andrea Santangelo IAAT, Eberhard-Karls Univerität Tübingen

Performances of the EUSO-Balloon

Functional requirements

R-4.1-1 Background imagingThe Instrument shall image the UV sky background in the bandwidth used by the JEM-EUSO mission observational technique.The background includes star light, airglow, light from artificial sources. Test of the trigger algorithms, switch between observational modes R-4.1-2 Detection of EAS (from the edge of space)The Instrument shall trigger, detect and image EAS with energy above 1018 eV that might develop in the field of view.R-4.1-3 Technology demonstratorAll key components and the relative sub-assembly items should be tested according to the configuration foreseen for the JEM-EUSO mission.This is needed to test the JEM-EUSO detection chain.

UPDATE: Test capability of the IR-CAM; Test of laser induced EAS.

CDR – 18.12.2012

Performances of the EUSO-Balloon 2

3

Nightglow background: 100 - 500 photons/m2/ns/srSakaki, BABY, NIGHTGLOW, Tatiana

increases by ~1.5 with cloudsAirglow (~100 km height): 250 - 600 photons/m2/ns/srMoon phases (<25%): <100 ph/m2/ns/sr

500

1000

2000

From Tatiana Universitetsky Satellite. a and b = large cities

ph/m2/ns/sr

Background measurements with coarse resolution (~200 km FoV)

On the night-sky background.

Performances of the EUSO-BalloonCDR – 18.12.2012

CDR – 18.12.2012

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Baby vs. Tatiana and the EUSO-Balloon

The Baby (Balloon) Experiment had a reduced field of view with respect to Tatiana stronger contrast, fluctuations

Balloon trajectory

EUSO-Balloon:a) will have finer resolution at ground (~200m)

b) will implement a control on background variations to keep a stable trigger rate (~7 Hz)

O.Catalano et al., NIMA 480 (2002) 547

Performances of the EUSO-Balloon

Background simulation

An example of background observation

250 photons / m^2 ns srUniform distributionSimulated at electronics level

The EUSO Simulation and Anlaysis Framework has been used for the simulation

Performances of the EUSO-BalloonCDR – 18.12.2012

CDR – 18.12.2012

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Testing switches

The logic of switches of EUSO-Balloon will be tested to verify:a)Capability of protecting the detector from bright eventsb)Measure their light curve and intensity

TLE jet

Power 104 W

Duration 0.4 s

Radius 40 kmHeight in atm. Troposphere

WITH SWITCHES

250 pC

Performances of the EUSO-Balloon

The observation principle of JEM-EUSO

Simulation of the light profile observed at the entrance pupil (above) and throught the instrument using the ESAF code

duration ~ 50 – 150 ms

Performances of the EUSO-BalloonCDR – 18.12.2012

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8

EUSO-BALLOON vs. JEM-EUSO

JEM-EUSO EUSO-BalloonHeight(km) 420 40

Diameter(m) 2.5 1FoV/pix(deg) 0.08 0.25

Pixel@ground(km) 0.580 0.175FoV/PDM(deg) 3.8 12

PDM@ground(km) 28.2 8.4Signal Ratio 1 17.6

BG Ratio 1 0.9-1.8S/N 1 20-10

Ethr(eV) 3x1019 1.5-3x1018

Number of PDM 143 1Maximize performance of EUSO-Balloon keeping parameters as close as possible to JEM-EUSO

Performances of the EUSO-BalloonCDR – 18.12.2012

Balloon Configuration modified „Alcala Config“, that is modified JEM-EUSO

1. ISS altitude 400 km 40 km2. New focal surface parametrization3. New pixel angle map5. New optical system6. Changed FOV: 2*30° 12*12°7. Background estimation ~ 50% of JEM-EUSO

Simulations

Performances of the EUSO-BalloonCDR – 18.12.2012

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Example Shower: 1e19 eV, Theta=20°

CDR – 18.12.2012

Performances of the EUSO-Balloon 10

Example Signal Track

• Proton• 1e19 eV• Theta= 20°• Phi= 135°

CDR – 18.12.2012

Performances of the EUSO-Balloon 11

Example Signal Track

• Proton• 1e18 eV• Theta= 30°• Phi=120°

• Proton• 1e19 eV• Theta= 30°• Phi=120°

CDR – 18.12.2012

Performances of the EUSO-Balloon 12

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phe/GTU

Time(GTU)

Time(GTU)

Time(GTU)

Xpix

Ypix

Ypix

Xpix

Proton:

E = 4·1018eVq = 57.5f= 188.7X0 = 9.3 kmY0 = 3.1 km

phe/

GTU

Event landing outside the FoV

Typical event observable by EUSO-Balloon: other code

So called: “Saitama” code

CDR – 18.12.2012

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Angular Resolution

Testing mode: „Debug mode“ a priori knoweldhge of the track

14CDR – 18.12.2012

Performances of the EUSO-Balloon

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Energy(eV)In

tegr

ated

N. E

vent

s [1

018,E

]eV

in 1

0h

LEFT PLOT: Trigger efficiency curve for events with impact point inside FoV.RIGHT PLOT: Black, red and blue curves give preliminary results on the performance from a 10 h duration flight for different assumptions of background and cosmic ray flux.

7 Hz/PDM

Trig

ger e

ffici

ency

(%)

Energy(eV)

Efficiency=1 & 1.5 x Aug. fluxEfficiency=1 & Auger fluxEB & A.fl. & <B>=1.4 pheEB & 1.5xA.fl. & <B>=1.4 pheEB & A.fl. & <B> =2.8 phe

EUSO-B. & <B>=1.4 phe/pix/GTUEUSO-B. & <B> =2.8 phe/pix/GTU

● 80 Hz fake trig.o 7 Hz fake trig.

Trigger Efficiency

CDR – 18.12.2012

Performances of the EUSO-Balloon

Conclusions

EUSO-Balloo will IMAGE the UV sky background (star light, airglow, TLEs, artificial lights) in the bandwidth used by the JEMEUSO mission observational technique.

All key components and the relative sub-assembly items will be tested according to the configuration foreseen for the JEM-EUSO mission: in particular the trigger scheme and its capability to cope with the variable sky conditions (EXTREMELY IMPORTANT).

Simulation studies have been performed: to understand the structure of the expected signal and the effective energy threshold of EUSO-Balloon and its possibility to detect showers. Results confirm the capability of the instrument of detecting primary cosmic rays of energy E>1018 eV. Due to the low cosmic ray flux the detection of a couple of events will require few days exposure time therefore the detection of the first air shower from the edge of the space will most probably require more than one flight.

CDR – 18.12.2012

Performances of the EUSO-Balloon 16