1. The LOFT-WFM for eXTP – Possible configurations
Margarita Hernanz
Laura Alvarez
on behalf of the LOFT/WFM team
CSIC-IEEC, Barcelona
Spain
e-XTP meeting
IHEP, Beijing, China
26-27 October 2015

2. First eXTP configuration with LAD panels and WFC; no WFM

3. Geometry of the cameras: as in LOFT/WFM

4. A camera pair with its sunshield
Minimal distance to the sunshield: 375 mm

5. First configurations: they minimize the changes of instruments in the original eXTP baseline (prior to Roma Sept meeting)
Configurations O# (Old #, with # the number of units)

6. Configuration O2a: 2 units=2 camera pairs
Location
In place of XTP/HCAs
Problems
Sunshield out of the optical bench
Part of the FoV of the cameras would be obstructed by the central cylinder
Conf.1 in doc

7. Configuration O2b: 2 units=2 camera pairs
sunshield: cylinder wall a bit taller
* 2 HFAs (original size) removed
* 10 LFAs relocated
+15º,-15º: offset angles of the cameras wrt optical axis (trial) Other options: see later
Conf.2 in doc

8. Configuration O2b: 2 units=2 camera pairs

9. sunshield: cylinder wall a bit taller
Configuration O4: 4 units: 3 in arc + 1 antisun (4 camera pairs). Identical to M4 LOFT/WFM
sunshield: cylinder wall a bit taller
* 3 HFAs (original size) removed
* 10 LFAs relocated
0, +60º,-60º: offset angles of the cameras wrt optical axis
Conf.3 in doc

10. Configuration O4: 4 units: 3 in arc + 1 antisun (4 camera pairs)
Configuration O4: 4 units: 3 in arc + 1 antisun (4 camera pairs). Identical to M4 LOFT/WFM
3 HFAs (original size)removed
Including the antisun unit does not have much impact on the accommodation

11. New configurations, based on the new eXTP baseline - LFAs and HFAs with the same size, no HCAs - but without the “cylindrical sun shield”
WFM located at the center or at the edge of the platform
Notation: configurations N# (New #)

12. Configuration N2a: 2 units=2 camera pairs
10 LFAs relocated
5 additional LFAs/HFAs
+30º,-30º: offset angles of the cameras wrt optical axis
Conf.7 in doc

13. Configuration N2a: 2 units=2 camera pairs
10 LFAs relocated
5 additional LFAs/HFAs
+30º,-30º: offset angles of the cameras wrt optical axis
Bad coverage of optical axis direction

14. Configuration N2b: 2 units=2 camera pairs asymmetrical, perpendicular to each other
10 LFAs relocated
5 additional LFAs/HFAs
+15º,-75º: offset angles of the cameras wrt optical axis (90º)
Better coverage of optical axis direction
Conf.6 in doc

15. Configuration N2b: 2 units=2 camera pairs asymmetrical, perpendicular to each other
10 LFAs relocated
5 additional LFAs/HFAs
+15º,-75º: offset angles of the cameras wrt optical axis (90º)
Better coverage of optical axis direction

16. Configuration N3: 3 units in arch (3 camera pairs) M4 LOFT/WFM-like but without the antisun
WFM at the edge (a bit elevated)
Sunshield height: 1.30m
10 LFAs relocated +
5 LFAs / HFAs
0, +60º,-60º: offset angles of the cameras wrt optical axis
Conf.5 in doc

17. Configuration N3: 3 units in arch (3 camera pairs) M4 LOFT/WFM-like but without the antisun
WFM at the edge (a bit elevated)
Sunshield height: 1.30m
10 LFAs relocated +
5 LFAs / HFAs

18. Configuration N4a: 4 units: 3 in arc+1 antisun Like M4 LOFT/WFM - WFM at the center
10 LFAs relocated
Conf.4.1 in doc

19. Configuration N4a: 4 units: 3 in arc+1 antisun Like M4 LOFT/WFM - WFM at the center

20. Configuration N4b: 4 units: 3 in arc+1 antisun Like M4 LOFT/WFM - WFM at the edge
10 LFAs relocated
Conf.4.2 in doc

21. Configuration N4b: 4 units: 3 in arc+1 antisun Like M4 LOFT/WFM - WFM at the edge
10 LFAs relocated:
but there’s room for more LFAs

22. Configuration N4c: 4 units: 3 in arc+1 antisun Like M4 LOFT/WFM - WFM at the edge
10 LFAs relocated
3 additional LFAs /HFAs

23. Configuration N5: 5 units=10 camera pairs Like LOFT M3

24. Configuration N5: 5 units=10 camera pairs Like LOFT M3
Difficult to accommodate 10 LFAs: 8 OK but the 2 additional LFAs would be too close to the sunshield

25. Summary
Several WFM configurations with 3 camera pairs in arc (and even with 3 arc +1 antisun) can coexist with at least 10 LFAs (and can include up to 15). But this of course depends on exact details of the XTP platform, LFAs dimensions and distances between each other.
WFM configurations with 3 camera pairs are not more constraining than those with 2, but the gain in science with 3 would be very relevant (see other talks about science and about WFM):
Preferred configurations:
N3: 3 camera pairs in arc + 15 LFAs
N4c: 4 camera pairs (3 in arch + 1 antisun) + 13 LFAs
The sunshade shape and dimensions are crucial. A rectangle instead of a cylinder would act only where needed and thus be lighter