Gain Calibration for GE1/1 Prototype

1. Gain Calibration for GE1/1 Prototype AndreyMarinov and Michal Zientek RD 51 Mini Week – January 2011

2. Tests in the RD51 Lab After the beam test in October we put the detector in RD51 for full set of tests in order to document all important parameters as the gain of the detector. GE1/1 in the X-Ray setup RD51 mini week. Jan. 2011

3. Gain measurement plan • Using the Ital Structures 3k5 X-Ray generator in RD51 lab. • Comparing with 10x10cm SM small prototype, well known. • Taking to account all the major differences between thesetwo detectors: • HV dividers • 3mm Aluminuim plate in the front of drift electrode in GE1/1 RD51 mini week. Jan. 2011

4. HV Dividers The difference in the total resistivity between the two dividers is 27.6kΩ GE1/1 has less GEM voltages with respect of the 10X10cm SM small prototype RD51 mini week. Jan. 2011

5. 3mmAluminium Plate 10x10cm SM in the X-Ray chamber GE1/1 exploded CAD view 10x10cm SM with 3mm Al plate in the front RD51 mini week. Jan. 2011

6. Role of the Aluminum Plate in front of the Drift Electrode RD51 mini week. Jan. 2011

7. hν Aluminum Absorption 1. 2. 3. Kα, Kβ, Kγ emission mechanism RD51 mini week. Jan. 2011

8. Gain Calculations RD51 mini week. Jan. 2011

9. ADC Scale Calibration Instead of energy on x axis, there are channel numbers. In order to estimate energy, we need to calibrate the scale by putting in to the X-Ray chamber a reference source, like 55 Fe. With two known values (55Fe kα2 = 5.9keV and Cu kβ2 = 8.9keV), we are able to calibrate the scale. Ei[keV] = 0.0585334channeli – 0.00298279 While using a GEM without Al cover we can accept 8.9 keV as a value of an energy. With the Al cover we have to estimate the mean of whole spectrum, due to the tail (peak, bump) we have. We can do that in a following way: RD51 mini week. Jan. 2011

10. GE1/1 Gain Calibration Curve RD51 mini week. Jan. 2011

11. Thank You RD51 mini week. Jan. 2011