MAX Baseline :

STACK OF FOUR PLANAR X-Y STRIP DETECTORS

Drawing of the strips of one face:

Technical specs for a stack of 4 planar with X-Y strip:

For each planar detector:

Planar detector with 40 strips of 2mm pitch on each side (X perpendicular versus Y).

The four corners of the detector will be cut off.

This will define a square useful surface of 80 X 80 mm limited in the corners by a circle of 100mm diameter.

A guard ring of 4mm width will surround this useful measuring volume.

This guard ring may be used as a veto detector.

The detector will be realized in double side thin window technology

The entrance and exit window of each detector will be less than 0.5 microns equivalent germanium.

Each detector will be mounted in a ceramic canister allowing the fan out of the 81 segments (40 X strips – 40 Y strips – guard ring).

This fan out will be out of a low thermal conductive material (to minimize the necessary cooling power).

The canister will have a thin window (less than 1mm equivalent aluminium ) on both entrance and exit surfaces

The detector clamping will be made in such a way to survive vibration tests (level to be defined).

The canisters will be fabricated in such a way to allow them to be closely packed together.

We expect the following gaps germanium to germanium

§ Gap detector 1 to detector 2: 5mm

§ Gap detector 2 to detector 3: 8mm

§ Gap detector 3 to detector 4: 5mm

The resolution obtained on each of the 320 strips in strongly depending of the total room allowed for the wiring, the design of the preamplifiers and the power allowed to each FET.

With laboratory operating (not cooled) preamplifiers we expect to obtain per strip: 1.6 keV at 122 keV and 2.4 keV at 1332 keV

MAX option 1:

ENCAPSULATED AND SEGMENTED GE DETECTOR

TECHNICAL DESCRIPTION:

The detector is a single open end coaxial N type Germanium detector.

Dimension of the Germanium detector :

§ The diameter is 80mm

§ The length is 80mm

§ Diameter of the hole: 10mm

§ Depth of the hole: 55mm

Two chamfers are provided on the front and rear face to secure it safely during vibration.

The external electrode is segmented in 9 segments.

This segmentation consists in 8 equal angular sectors and one central disk of 20mm diameter.

There will be no groove or any absorbing material between the segments.

The detector will be passivated even between the segments.

The detector is mounted in a ultra high vacuum canister in such a way to withstand a “integral level” vibration test.

The canister is made of aluminium and is provided with fixing threads which have to be defined.

The entrance window of the canister is 1mm aluminium.

The resolution of the different segments depends strongly of the preamplifier design and of the allowed power on the FET.

With “laboratory” preamps we can expect following FWHM:

§ Full volume channel: 2.3keV on ⁶⁰Co and 1.2keV on ⁵⁷Co

§ All 9 external channels : 2.1keV on ⁶⁰Co and 1.2keV on ⁵⁷Co

The canister will be guaranteed annealable a given number of times (to be defined).