E-mail: zhzhy@mail.ustc.edu.cn Manufacture and performance of three 200×200mm² thermal-bonding Micromegas prototypes Zhiyong Zhang（张志永）, Liang Guan（管亮）, Xiaolian Wang（汪晓莲）, Tianchi Zhao（赵天池） 核探测与核电子学国家重点实验室 中国科学技术大学近代物理系 E-mail: zhzhy@mail.ustc.edu.cn 2014/07/19-07/20

Outline Basic principle Manufacture Test system Performance Summary 2014-7-20 山东大学 威海 第四届微结构气体探测器研讨会

• Basic principle Stainless steel mesh Y. Giomatnris, et al., MICROMEGAS: a high-granularity position-sensitive gaseous detector for high particle-flux environments, 1996 Nuclear Instruments and Methods in Physics Research A 376 29-35. Y. Giomatnris, Development and prospects of the new gaseous detector “Micromegas”, 1998 Nuclear Instruments and Methods in Physics Research A 419 239-250 2014-7-20 山东大学 威海 第四届微结构气体探测器研讨会

• Manufacture » Structure » Materials Compressed air Stretched mesh Hot plane Spacers Readout PCB MicroMesh: 350 LPI woven stainless steel mesh pitch/wire diameter 75/24 μm tough polyester films with a permanent, dry (hot-melt type) adhesive on both sides The intrinsic volume resistivity of Ge (house temperature):59ohm.cm Germanium Plated PCB The readout PCB with a Germanium plated layer (0.1-0.5μm thickness, ~2MΩ/口) Thermal-bonding film spacers and frame are placed on the PCB. Double avalanche gaps are achieved on both side of the readout PCB. 2014-7-20 山东大学 威海 第四届微结构气体探测器研讨会

» Bonding condition Active area (mm²) 200×200 Number of spacers 173   Mm01 Mm02 Mm_Ge Active area (mm²) 200×200 Number of spacers 173 200 ~200 Dimension of spacers (mm) 4 3 Spacer area (%) 5.43 3.53 3.85/3.34 Tension of mesh (N/cm) 19/20 19.5/19.5 Bonding time 70/70 69/69 65/65 Temperature (up) (oC) 116/118 116/115 120/117 Temperature (down) (oC) 138/132 130/130 144/139 Pressure (kg) 125/110 124/120 119/127 2014-7-20 山东大学 威海 第四届微结构气体探测器研讨会

» Fabrication HV test in clean room After bonding 2014-7-20 山东大学 威海 第四届微结构气体探测器研讨会

• Test system Mobile scanning platform , x-ray gun, shielding box et.al.. Gas system DAQ system NIM crate and HV, logic plug-in board 2014-7-20 山东大学 威海 第四届微结构气体探测器研讨会

• Setup Gas Mixture: Ar+CO2(93:7); Flowing gas mode; Scanning with a ⁵⁵Fe source and a Cu-target x-ray gun; 2014-7-20 山东大学 威海 第四届微结构气体探测器研讨会

• Performance » Spectrum of ⁵⁵Fe source (Mm01) Gas Mixture: Ar+CO2(93:7); Kalpha: 5.9keV; Kbeta: 6.5keV; Fitted by triple gauss function + linear noise; 2014-7-20 山东大学 威海 第四届微结构气体探测器研讨会

» Absolute gain (left) » Energy resolution versus gas gain (⁵⁵Fe source 5.9keV x-rays) (right) 2014-7-20 山东大学 威海 第四届微结构气体探测器研讨会

⁵⁵Fe source Scan direction: » Gain non-uniformity ⁵⁵Fe source Scan direction: 20cm×20cm active area The gas gain is mainly depend on the avalanche gap，which is determined by the flatness of hot plate, heating time, and pressure etc. 2014-7-20 山东大学 威海 第四届微结构气体探测器研讨会

Cu Kalpha x-rays source scanning (perpendicular to the strips): » fine scan (Mm02) Cu Kalpha x-rays source scanning (perpendicular to the strips): 20cm×20cm active area Fine scan the active area with a Cu-target x-ray gun in a ~15mm range, about ± 5% non-uniformity is obtained, which will affect less for the spatial resolution, since the cluster size of avalanches is smaller than 1 mm. 2014-7-20 山东大学 威海 第四届微结构气体探测器研讨会

Pulse shapes are fitted (range: 2~3*rise time) with sigmoid function: » Pulse analysis Signals from preamplifier are digitized and recorded through Digital Oscilloscope for offline analysis Pulse shapes are fitted (range: 2~3*rise time) with sigmoid function: Signal Amplitude and Rise time are extracted from the fitted function. Rise time: 𝐴 𝑡 =− 𝑝 0 1+ 𝑒 𝑡−𝑝 1 𝑝 2 +𝑝[3] Risetime:110ns 𝑇 10%−90% =4.39∗𝑝[2] 2014-7-20 山东大学 威海 第四届微结构气体探测器研讨会

» Rate capability study The Germanium layer is around connected to the ground. Cu X-rays tube(8KeV) source 150-5000μm 100-5000μm collimator Micromegas 2014-7-20 山东大学 威海 第四届微结构气体探测器研讨会

The gain versus x-rays rate with different surface resistivity. » Rate capability The gain versus x-rays rate with different surface resistivity. T. Alexopoulos, et.al., A spark-resistant bulk-micromegas chamber for high-rate applications, 2011 Nuclear Instruments and Methods in Physics Research A 640 110–118. 2014-7-20 山东大学 威海 第四届微结构气体探测器研讨会

» Stability Source: 5.9keV x-rays Operated at a gain of ~9300; Radiation rate:150Hz 2014-7-20 山东大学 威海 第四届微结构气体探测器研讨会

• Summary ◊ The thermal-bonding method had been developed to manufacture the Micromegas, the manufacture and performance are presented. ◊ High gain and good energy resolution are obtained with the 200×200 mm² prototypes. ◊The rate capability and stability are also studied, further improvements need to be carried out. Further plan： ■ Try to improve the uniformity efficiency and rate capability of resistant anode chamber. ■ Develop the new structures like PIM, Backplane. ■ Setup a telescope for cosmic test of BGO ECAL of DAMPE, if it is needed. Thank you! 2014-7-20 山东大学 威海 第四届微结构气体探测器研讨会