Abstract
The ATLAS upgrade strip module design has readout flex circuits glued directly on top of the sensor’s active area to facilitate the assembly process and minimize the radiation length. The process requires radiation-hard adhesives compatible with the sensor technology. We report on the studies of the breakdown behavior with miniature versions of the prototype sensors, where candidate adhesives were placed in several locations on top of the sensor, including the strip area, guard ring region, and sensor edge. Thermal cycling tends to attenuate the observed cases of breakdown with glue on top of the guard ring. Glue reaching the sensor edge results in low breakdown voltage if it also covers AC- or DC- pads or bias ring openings. Glue placement on top of guard ring region was performed on a large-format sensor, with generally similar results to the miniature sensor tests, except for a large glue deposition, which resulted in a permanent reduction of the breakdown voltage. Post-irradiation measurements were performed for some of the glues deposited on top of the strip area, without any sign of the early breakdown. To help rank the candidate glue, we studied them with differential scanning calorimetry to find the glass transition and degree of curing.
Highlights
We have performed two separate studies to check compatibility of a variety of glues with the prototype n-on-p sensors.Study A: o Glues: Epolite FH-5313, Loctite 3525, DYMAX 3013, DYMAX 6-621 o Sensors: ATLAS07 [2] o Placement: active area o Irradiation: yes STUDY A: IRRADIATIONSome of the sensor-glue samples used in Study A were irradiated with protons at KIT and Los Alamos, as well as with neutrons in Ljubljana
In Study B initially the glue drops were placed on top of guard ring (GR) region, to find out if this is a dangerous location for the glue (Figure 5)
The study of the breakdown behaviour in this case showed a strong reduction of the breakdown voltage in most cases (Figure 6)
Summary
We have performed two separate studies to check compatibility of a variety of glues with the prototype n-on-p sensors.Study A (more details can be found in [1]): o Glues: Epolite FH-5313, Loctite 3525, DYMAX 3013, DYMAX 6-621 o Sensors: ATLAS07 [2] o Placement: active area o Irradiation: yes STUDY A: IRRADIATIONSome of the sensor-glue samples used in Study A were irradiated with protons at KIT and Los Alamos, as well as with neutrons in Ljubljana. We have performed two separate studies to check compatibility of a variety of glues with the prototype n-on-p sensors. Study A (more details can be found in [1]): o Glues: Epolite FH-5313, Loctite 3525, DYMAX 3013, DYMAX 6-621 o Sensors: ATLAS07 [2] o Placement: active area o Irradiation: yes STUDY A: IRRADIATION Some of the sensor-glue samples used in Study A were irradiated with protons at KIT and Los Alamos, as well as with neutrons in Ljubljana.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
