Philippe Gorodetzky - EUSO collaboration PCC / APC - Collège de France XIII ISVHECRI Pylos, September 6-12, 2004 An Innovative Space Mission doing astronomy

Philippe Gorodetzky - EUSO collaboration PCC / APC - Collège de France XIII ISVHECRI Pylos, September 6-12, 2004

An Innovative Space Mission doing astronomy by looking downward from the Space

Station at the Earth Atmosphere

Extreme Universe Space Observatory

Vincent Van Gogh, “The starry night”


hadron collisions: large energy density (1)

Classical hadron interaction (Ep < 1018 eV)A large part of the energy goes into the leading particle (often the same as projectile).The reaction is fast.

At energy density > 3 MeV/fm3 (Ep> 1018 eV) thermalisation can occur.Same basic phenomena than Quark-Gluon-Plasma (deconfinement)The reaction is slow.No more leading particle. The energy goes into transverse energy (ET increases).

Fast interaction(leading particle)

Slow interaction(thermalisation)

Basic illustration(fluo vs ground?)


Hadron-hadron collisions with cms energies where there is an especially large (no jets) transverse energy release. The high-multiplicity, high ET collision debris will expand outward the collision region at the speed of light for a few fermi before decoupling in real hadrons.

Disoriented Chiral Condensate (DCC)(Baked Alaska); a theory by J.D. Bjorken (1)

- J. Bjorken Results and perspective in particle physics. Rencontres de la vallée d’Aoste. M. Greco editor, 1993- G. Amelina-Camelia, J.D. Bjorken and S.E. Larsson Pion production from baked-Alaska disoriented chiral condensate; Phys Rev D 56(1997)6942

Incident hadrons

Hot Shell

s s

Hadrons

DisorientedChiralCondensate

( )a ( )b ( )c

At intermediate times, we have a hot thin shell with a relatively colder interior which will relax to something akin a vacuum. This vacuum is almost degenerate owing to the chiral symmetry, which is spontaneously broken.This vacuum will radiate its pionic orientation, which is the observable of interest. So, if the deflection of the vacuum is in the 0 direction, all condensate will be 0’s (anti-Centauro) and if orthogonal, all pions will be charged (Centauro). These pions, emitted from a large volume, have a low pT


Disoriented Chiral Condensate (DCC)(Baked Alaska); a theory by J.D. Bjorken (2)

This JACEE event (p interaction in calorimeter) is evidence for “texture” in the

lego plot

Basically: assuming that the event-by event deviation of the quark condensate from its usual orientation, one finds that the distribution P(f) of the neutral fraction is given by

at large Ntot

Most notably, this implies that for Disoriented Chiral Condensate, the probability of finding extreme values of f is very different from ordinary pion production (which is given by a binomial distribution), in which the fluctuations are expected to be peaked at f = 1/3 and fall exponentially away from the peak.

€

f ≡0

πN0

πN + +

πN + −

πN≡

0

πNtotN

€

dP

df≡

1

N

dN

df=

1

2 f

P

f

DCC distributionP

f

binomialdistribution

10-5

0,0001

0,001

0,01

0,1

1

0 2 4 6 8 10

frequency of events (f > 0.9)

N

DCC

Binomial

The most favorable are p-nucleus reactions (sizable matter to traverse,but still a thin hot shell.So, how do fluo and ground measurements behave in these conditions?

3 5 7 9h0

90

180

270

360photons chargedparticles

4 -27JACEE LIIGSEg = 15.4 TeV

proton primary

photonthreshold


Calorimetry vs patternIf the ratio of the electrons to the charged pions in a shower stays constant, its

repartition in rapidity bins could very well be not uniform. This is not too important when looking at the fluorescence, for it is a calorimetric measurement. (and furthermore the number of electrons at the shower max is extremely stable and proportional to energy), even if the electrons repartition in is not uniform.

However, if one looks at the pattern of particles hitting the ground (the ratio of particles outside a circle to particles inside), the result will not be so robust, on an event-by-event showers with the same energy.

The high ET of the first hadronic collisions will put more particles outside, and is it not what seems to be observed?

Fluorescence measurements are then probably more precise in energy determination.

Angular resolution is also more precise for the statistics in photo-electrons (fluo) are better than those on ground stations (at least for muons which are alone for inclined showers).


How to check (if a problem exists)

The crucial plot.

A piece of cake for AUGER!

And, why wait?K.H. Kampert just showed it!

Ground energy (1020 eV)0.01 0.1 1 10

Deconfinement ?(or something else)

(1st preliminary hybrid event shown in Florence, now

many more points)


Has the GZK suppression been discovered?J.N. Bahcall and E. Waxman

hep-ph/0206217 v5 27 Feb 2003

In this important paper, Bahcall and Waxman claim that there is no need for exotic new physics to account for the observed events with energies greater than 1020 eV, except for the AGASA data.They adjust individually the absolute energy calibrations of the various experiments (with fractional E shifts all well within published systematic errors in E) so that they agree @ 1019 eV, and find that the agreement is excellent from 1018 to 5x1019 eV. -------> A fit with their “Extra-Galactic +

Galactic and No GZK (an extrapolation of the E-2.75 energy spectrum in the precise region 6x1018 to 4x1019eV)” is shown on the left.The table compares the events above 1020 eV and shows a strong deficit (>5) of observed events. Hence, this is a strong suggestion that the GZK cutoff has been observed. But this is based ONLY in the precise data at “low” energy ---> we need precise data from 5x1019 to 1021 eV.

--------------------------------------------Energy scale Expected Observed--------------------------------------------Fly’s Eye 34 4AGASA 40 6Yakutsk 46 6

Envelope of EUSO data in five years if No GZK


SPACE vs GROUND (1)

ESA's Integral detects closest cosmic gamma-

ray burst 5 August 2004

A gamma-ray burst detected by ESA's Integral gamma-ray observatory on 3 December 2003 has been thoroughly studied for months by an armada of space and ground-based observatories. Astronomers have now concluded that this event, called GRB 031203, is the closest cosmic gamma-ray burst on record, but also the faintest. This also suggests that an entire population of sub-energetic gamma-ray bursts has so far gone unnoticed...


SPACE vs GROUND (2)AMS

AMS shuttle

NO PRECISION…NO HOPE!

p

He

AMS ISS

Parametrization (R) = 0R with R (rigidity) in GV


What EUSO looks like


Fixed

Moving

SIZES

High statistics

Target mass: 1012 - 1013 tons


EUSO: Who does what ?

Optics : USA ≈ 2m

Photo-detector : Japan≈ 200 000 pixels

Mechanics : France - Italy

Electronics : France - ItalyAnalog - Digital

Ground Segment : PortugalLIDAR : Switzerland - Italy


US Optics I

QuickTime™ et undécompresseur TIFF (non compressé)sont requis pour visionner cette image.




CYTOP?

The ISS is known to move quite a lot.

A lens (refraction) tilt produces a smaller movement of the image than a mirror (reflection) tilt.


French activities LPSC (Grenoble) & APC/PCC (Collège de France)

Analog electronicsFront End

Mechanics and thermalstudy of the focal surface

Simulations - ESAFAtmosphere

Analysis, Lidar

CommunicationOutreachF.Vannucci


Thermal conductivity of FSA(Summer, 6 m2, 850/200W)

Text -T

int


And elsewhere…

Japan

Italy-Alenia

USA

ESA

Germany(Munich)calibrations


Acceptance and counting rates I

Shower, detector and trigger simulation:

Shower production : Corsika -> parameterization GIL Photons production : Fluorescence (Kakimoto et al.) and Cerenkov

Atmosphere transport : Rayleigh, Mie, Ozone (LOWTRAN7) Optics : Transfers and aberrations

Photo-detectors : Filters and quantum efficiency Trigger : Thresholds and persistence (Nthre, Npers)


Acceptance and counting rates II

The absolute threshold is anchored by ∆ and the detection efficiency.The trigger performances determine the acceptance evolution versus energy.

The asymptotic efficiency will be determined by the cloud coverage.

Efficiency times the power -2.7 law


Clouds effects IThe cloud coverage will play an important role :• Eventually mask part of the shower (Smax),• Increase the Cerenkov light reflection;

The cloud coverage is given by the ISCCP database : 280x280 km2 pixel size: Longitude, latitude, every 3 hours --> altitude, albedo, cloud fraction.


Clouds effects II

Clouds reduce efficiency from ≈ 86% ≈ 53%

NO CLOUDS CLOUDS


Clouds effects versus shower energy

E = 5x1019eV E = 5x1020eVE = 1x1020eV


Duty cycle

Duty cycle (time fraction usable for measurements) depends on the "photon background" :Without moon, this background is estimated (measured) to 300 ph/m2/nsec/srIt originates from the stars light and to the "Airglow"It does not depend critically on the cloud coverage (≈ +20%)Moonlight will limit the duty cycle.

• for12.8% of the time, moon is under horizon,• for 18% light increase is insignificant,• for 25% light increase < 100 ph/m2/nsec/sr.

To that, too short nights have to be removed (<10% of them).Euso has a warranty of a 3 years effective measurement time (and, see this talk end, if JAXA HTV is used, there is no return).


A possible measurement …(duty cycle 12%)

NevtGZK (E >1020 eV) >100

Super-GZK, in the French terminology, really means: No GZK

Courtesy of AGASA


Angular resolutionPrecise showers analysis will be made on an “event by event” basis: each shower will get errors specifically depending of the observation conditions.

As of today, only a statistical error estimation is considered. Angular resolution : ∆ < 1° if shower > 60°


Energy resolution, errors I“End-to-End” simulation software allow to estimate errors (statistical and systematical) associated to all parameters:

Fluorescence, quantum effic., optics transmission, temperature, density, atmospheric transmission, angle,…


Energy resolution, errors II

€

E =Ec

Xrad

N e(X )dX∫

dNpe

dL=

N e(X )

4πR2Slens Y (λ ,X )Tatmos(λ ,X )∫ QE(λ )ε filter (λ )Tlens(λ )dλ

Nature Error

Missing energy 5%

E e- 5%

Method + (1st Int. + Nb of p.e) 10%+10%

e- fluorescence 20% -> 10%

Atmospheric correction 15%

Optics + detector 10%

Temperature and Pressure 5%

shower (2°) 2%

Mass (p -Fe) 5%

Total 27%


Horizontal showers and Neutrinos• Shower length depends on the encountered density• Fluorescence production (O2 being a quencher) depends only on altitude (< 15km) Shower width (∆T) will then depend only on altitude.


Neutrinos and Hadrons showers

• The probability to observe an (≈ horizontal) hadronic shower with a maximum under 10 km is extremely weak.

• Instead, this probability is maximum for neutrinos.


Neutrinos acceptance and boundary fluxes

EUSO total acceptance for neutrinos (interacting in atmosphere) is ≈ 0.15 x 10 km2.srCorresponding to a detection limit of J( E )*E2 ≈ 70 eV cm-2 sr-1

For horizontal showers (>85°), a 15 times increase is to be foreseen.

Neutrino acceptance is low, but if fluxes are adequate, the observation of an horizontal shower, under 10 km, should be the hallmark of neutrinos.The , interacting with the earth crust would have an acceptance x 10-100

Acceptance with identification

For horizontal showers (no ground array), the ratio of EUSO to AUGER areas is 100, plus- shower length ≈ AUGER F ==> full shower never observed in its totality- EUSO scans the whole sky


Ups and downs (and ups…)

Situation until June 2004:ESA: Science division is in charge. As we are phase A, they do not give money, but examine scientifically. In France, IN2P3 pays for phase A (INFN in Italy…).

NASA: Code S (Science) is in charge. In phase B and get money. Will be reexamined at end of phase B. But will not go further phases alone.

JAXA: ISS division. Are in phase A, going to phase B, Riken paying.

ESA ISS division (with Science div. Physicists) says EUSO passed phase A successfully.

June 04:ESA Science directorate says no to phase B for AUGER and Shuttle reasons. Real reason is money.A. Watson replies that AUGER first results will be in 05 and not 08 or 09. JAXA proposes their HTV to replace Shuttle.ESA MSM (ISS) division offers to replace Science division.

August 20 2004Director of Science division at ESA agrees that EUSO switches from his division to the MSM (ISS) division

(keeping control however).It looks like ASI (and CNES hopefully) finds this OK. Livio Scarsi is in Riken with ESA, NASA and JAXA.


Japanese docks

• JEM-EF in ISS

JEM-EF


Payload Interface/Resource

a. Power 3kW×2ch (120VDC) 2 locations (EFU#1,#2)

b. C&DH High rate data 8ch

Video data 8ch

Ethernet 7ch

c. TCS Maximum Heat Transfer Total 10kW (plug the cooling liquid).

More power (3 kW instead of 1 kW) means:

- more computing, hence a local trigger based on continuity of pixels ==> threshold can go down to less than 1x1019 eV (maybe even less,

see Hank Crawford) - PMT bases with more current ==> better stability


EUSO-HTV revised configuration: description

Batteries and Electronic

Boxes

Passive MCAS

FRGF (Focal Surface Module structure to be redesigned to support FRGF

loads)

Passive FRAM for on-orbit attachment of LIDAR

HTV I/Fs (wheels and TSM) supported by EUSO P/L structure

Radiator


HTV door problems

HTV

Door

EUSO horizontal in HTV(Alenia solution)

300 mm for the lid

200 mm for electronics, boxes, etc.

StopBellows

HTV DOOR

EUSO ENVELOPPE

Lens1

Lens2

Foc surf

Cytop diffractive July 05Scale = 1/20

30 cm free. If we add the 12 cm at the bottom, then we have 42 cm. Enough to accomodate LIDAR + fixations?

12 cm free

2765 mm

2695 mm

2500 mm

2450 mm

1750 mm

330 mm

Gain = 820 mm

Gain = 850 mm

Gain =500 mm1650 mm2080 mm

EUSO vertical in HTV(CdF, Riken & UAH solution)


In the future


Documents

Philippe Gorodetzky - EUSO collaboration PCC / APC - Collège de France XIII ISVHECRI Pylos, September 6-12, 2004 An Innovative Space Mission doing astronomy