Noise Scan Test & Flexible Web Test of STRAW Tracker

1. Noise Scan Test & Flexible Web Testof STRAW Tracker Thomas Pak 26-03-2012 CERN / NA62 (George Mason University)

2. Content • Front-End Electronics Noise Characteristics • The noise_scan_tp Script • Flexible Web Testing Method • Near-Future Perspectives & Anticipations

3. 1. Front-End Electronics Noise Characteristics • Thermal noise of the straws • Shot Noise of the straws • It seems the above 2 will be taken care of by the CARIOCA shaper. (Yet to be tested and investigated?) • High Voltage Input Capacitor Noise • CARIOCA’s internal white-noise

4. 2. noise_scan_tp Script • Originally written by Peter Lichard • Assumes Gaussian white-noise of CARIOCA’s input channels • Sends given number of test triggers with given threshold voltage to scans how many actually got registered at each channel. • 2 scan modes • Mode 1: Sends triggers to all channels at the same time (short) • Mode 2: Send triggers to each channel individually (long) • Outputs in …/noisescan_plots/ folder) • .txt file # of Pulses Registered in each channel & the white noise characteristics (mu’s and sigma’s) fitted for the scan data for each channel • .datfile to be used for gnuplot • .gpscript file for doing gnuplot • Automatically plots white-gaussian noises for all channels

5. 2. noise_scan_tp Script:Mathematical Background • Number of pulses expected to be registered at a channel • The script linearizes the above to find Vp and σ. • So far, the result have been: • Vp: ~0.805V σ : ~0.014V • But I expect this to somewhat larger, when flexible-webs and straws are attached. (Yet to be tested)

6. 3. Flexible Web Test • So far about 20 of them tested (About 20/week can be done); Test-Method Documentation underway! • The testing method is straightforward; put HV(2.2kV) flexible-web, and scan (using tdc_scan script) if there’s any shot-noise(s) accidentally being registered. • The HV capacitor is extremely sensitive needing cleaning and extra-care in handling 4. Strange Bahaviors • Leaving the webs overnight seem to stabilize the HV capacitors • For some reason, increasing to a higher voltage (2.4V) for 10 minutes and bringing back down to 2.2kV would expedite the stablizing process.  This method was used.

7. 3. Flexible Web Test: Basic Procedure • Clean the Frame • Installing the webs with an insulator between cathodes and anodes • Closing the Front-End cover • Injecting CO2/Ar gas mixture • Put 2.4kV on the web for 10 minutes • Reduce HV to 2.2kV and do tdc_scan

8. 4. Near-Future Perspectives and Anticipations • Uniformity of each CARIOCA chip’s noise_scan performance seems called for. • Noise_Scan would be needed when straws and webs are all connected together  This will determine the confidence level of a pion track detection (Since the decay mode is rare (~10-9) to begin with.) • Previous CARIOCA performance with a delta input (for muon tracks) had been conducted. (It assumes certain pulse characteristics.) If there’s a similar study done for STRAW tracker, it would be great to study the confidence level of this particular detector.

9. Acknowledgement • Dr. Augusto Ceccucci • Hans Danielsson • Peter Lichard • AntoninoSergi • Georgios “the Master” Konstantinou • Johan Morant • All others Thank you, for the help and support to bring me up to speed thus far!