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EUSO BALLOON phase A review CNES, 2.2.2012. Mechanical design of the instrument approach for integration and tests Peter von Ballmoos, IRAP Toulouse. EUSO BALLOON instrument overview. data processing. optical system. Photo detection. Payload architecture - conventions. - PowerPoint PPT Presentation
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EUSO BALLOON phase A review CNES, 2.2.2012
Mechanical design of the instrument
approach for integration and tests
Peter von Ballmoos, IRAP Toulouse
Payload architecture - conventions
PDM Platform 3 / lens 3
Platform 2 / lens 2
Platform 1 / lens 1
grooved surfaces
z
xy
Constraints on the instrument/gondola design
optics :
"12° (± 6°) of Alex "adopted to 95% by the "optics team"
- allowed tolerances vary from 0.2–4 mm (axial) 1-5 mm (lateral) for the 3 lenses.
- lens 3 has to be adjustable in z-direction by ± 2 cm
- distance between PDM-optics has to be adjustable by ± 2
- precision of distance PDM-optics is ± 1 mm
thermal :
- lens1 might get expose to temperatures as low as -60°C
- PDM and lens 2&3 should remain between 10°C and 20°C (TBC)
- need for cooling of the PDM is not to be excluded at this point.
- avoid condensation and ice on lenses (particularly lens 3)
operations :
- "integrity" requirement at the parachute opening 10g/5g
- prepare for recovery at sea
Alignment of the lenses and the PDM - tolerances
Objective : as representative as possible for JEM-EUSO design with short focal lenght (1.48 m) and fairly large FOV of ± 6°
~ 1,48 m1 x
1 m
± 4.2mm ± 2.7mm ± 0.2mm z tolerances TBC
x,y tolerances TBD
tilt tolerances TBD ± 0.2mm
Alignment of the lenses and the PDM
~ 1,48 m1 x
1 m
± 20 mm (res ± 0.1mm)
1) Platform 1 and platform 2 are directly fixed within the phone booth
2) Lens 3 shifts in z-direction by ± 20 mm
3) Distance - optics block (lens-1-2-3) is adjustable within ± 20 mm
Objective : as representative as possible for JEM-EUSO design with short focal lenght (1.48 m) and fairly large FOV of ± 6°
± 20 mm (res ± 0.1mm)
± 1 mm ± 1 mm
The mounting and alignment of the Fresnel lenses
The mounting of the lenses has to satisfy the following requirements :
a) minimize lens sag
b) optical alignment compatible with to the tolerances required
c) phonebooth must be watertight
d) lens thermal expansion/retraction
e) stability/simplicity
a) lens sag : the four arms of a spider shall support the only 8 mm thick PMMA lens to minimize deformation under its own weight.
b) alignment :
- axial reference (in z-direction) : inward pointing surface of the spider
length of the "nose" defines distance to platform
- lateral reference (x,y-directions) : "plug" in the center of the spider.
lenslens
spiderspider
platformplatform
z-reference plane
nose-length
The mounting and alignment of the Fresnel lenses
The mounting and alignment of the Fresnel lenses
c) watertight :
- seal between lens and platform makes phonebooth watertight.
at least lens 1 and 2 – lens 3 is mounted "from above" and might not
need to be watertight.
d) lens thermal expansion/retraction:
- the lens is fixed in its center
- only weakly constrained for expansion/retraction within the x-y plane. - pressure provided by the seal allows for minute movements related
integration and tests
integration at IRAP Toulouse,
clean/balloon hall
G. Roudil, IRAP
verification of geometry by use ofa laser tracker - B. Mot, IRAP
tests of imaging/PSFby use of IRAP collimators/lasers(in case the optics do not go to MSFC)
RISKS
Failure of mechanical subsystem
RI2.1 Fresnel lenses not matched by platform mechanics
Spider or Lenses can be re-machined easily
RI2.2 Fresnel lens(es) damaged or polluted during integration
Lenses will be protected at any time,
Protection removed for launch
RI3.2 Project exceeds available M/power resource envelope
Phase A to define tasks, organization and necessary manpower. Phase A review to assess this point.
"stabilized" gondola (LPMA, 2003)
The period of the oscillations is typically in the order of 20 s .
motto for scientific ballooning
"Success is the ability
to go from failure to failure
without losing your enthusiasm" Churchill