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

First eXTP configuration with LAD panels and WFC; no WFM

Geometry of the cameras: as in LOFT/WFM

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

First configurations: they minimize the changes of instruments in the original eXTP baseline (prior to Roma Sept. 2015 meeting) Configurations O# (Old #, with # the number of units)

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

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

Configuration O2b: 2 units=2 camera pairs

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

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

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 #)

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

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

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

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

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

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

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

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

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

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

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

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

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

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