Mechanics and Cooling Systems for the CBM STS SAINT-PETERSBURG STATE UNIVERSITY S.Igolkin, CONTENT 1.Si detectors plates 2.Module of detector 3.Carbon fiber frame 4.Detectors plates holder 5. Ladder support system 6. The parts of cooling system 7. Arrangement of detectors plates on a ladder 8. Typical construction of the ladder 9. Construction of STS station Nr Tilling and distances between sensors 11. Ladders installation and fixation Dubna, Russia October, 2008

Installation of Si detectors is offered to Carbon fiber space structure - Frame Similar structures have been successful used at creation design Of Inner Trecker System ITS of experiment ALICE Such space CF Frames have the best parities weight- rigidity and allow to create on their basis the finished assembly of detectors Ladders, including: -Hybrids ( silicon detectors or modules of detectors with cables and plates of end electronic - Basic fixing elements - Cooling system of plates of end electronics

Detectors module E 32

Carbon fiber frame Material: CF prepreg M55J/ 334EU Moduls of composit 27000Gpa

Detectors plates holder Materials: Fiber glass (E-glass + epoxy glue )

Each end of ladder have a final support. Final support consist of: some plate with precise basis elements (surfaces) and two prisms Assemblage of end supports and frame perform on the assembly jig at the same time with detectors holders. The precise of assembly jig ensure precise disposition the all elements of ladder Ladders support system

The parts of cooling system Coolant fluid

Option 1 - fixation detects plates in parallel of horizontal plane in chess order - Provide compact configuration but demands are bend of the cables Option 2 – fixation of detectors plats under an inclination -Provide compact configuration and dont demands are bend of the cables, but not conveniently for installation. Option 3 – fixation detectors plates in parallel Of the horizontal plane, each detector shifting in parallel in one direction. - Provide easy installation, but demands more place and increases zones of overlapping between ladders Arrangement of detectors plates on a ladder

Typical construction of the ladder

The position of detectors for Station 4 The position of Si detectors plates from centre: 1. 22x x x62 + [62x62]x3 2/3/4 - 42x62 +62x62 + [62x62]x3 5 62x62 + [62x62]x3 6 [62x62]x As we see, each subsequent ladder it turns out by exceptions of the central plates of detector

Nr 1 Nr 2, 3, 4 Nr 5 Nr 6 The length of the ladders for ST 4 Length of the ladder from centre to periphery of station decrease proportionally 40mm i.e. to a step of the carbon frame, but the length of the cables in the hybrids are kept.

Construction of STS station Nr 4 The station consist of 4 frames. On each are fixed 3 ladders with detectors. The frames with ladders are fixed on the slides of main support of STS

Tilling and distance between sensors

Ladders installation and fixation

Schematic fixation of frames on the main support STS Some slides for ladders frame are fixed on the main support of STS. The frames with ladders are positioned on the slide : for top support - ball on plane with flat springs for down support – ball on prism

The main current tasks 1. Определить и описать параметры тепловых потерь и провести предварительные расчёты условий обеспечения температурного режим эксплуатации кремниевых детекторов, Рабочая температура на плоскости детектора (-5грС) +/- Рабочая температура в объёме детектора……+/-….. Рабочая температура платы электроники гибридов …..не более Время непрерывной работы детектора (длительность сеанса)…….. Для предварительных расчётов можно использовать следующие данные: - Наиболее нагруженная зона - центральная зона плоскости станции, в частности детектор 22х62мм ( J=100мка/см2 U=300V ) - Тепловыделения на остальных пластинах детекторов уменьшаются от центра к периферии пропорционально радиационной нагрузке. - Тепловые потери на плате электроники гибрида 2W - Тепловые потери в кабелях отсутствуют В качестве хладогента для воздушного охлаждения использовать инертный осушенный газ (азот, гелий ?), для жидкостного охлаждения фреон. 2. Провести оптимизационные расчёты по механике углепластиковой фермы исходя из предложенных размеров и параметров материала. 3. Предложить концепцию системы охлаждения с учётом результатов предварительных расчётов