The development of the NIMISiS Bias Control GUI by Christopher Crane Mentor Dr. Sherry Yennello

1. The development of the NIMISiS Bias Control GUIby Christopher Crane Mentor Dr. Sherry Yennello

2. Outline • Overview of intermediate energy physics • Why use NIMROD? • NIMROD upgrade • What is a silicon detector and a photodiode detector? • What is a bias box? • Previous methods of setting channels and why use a graphical user interface? • Connecting NIMROD and Summary

3. Intermediate Energy Physics • Different kinds of particles and the necessity for different kinds of particle detectors • From fragment yields at intermediate energies • From isobaric ratios • We can learn about temperature • The asymmetry term in the equation of state* • Get isotopic distributions • Phase transition

4. Why Use NIMROD? • NIMROD consists of telescopes and super telescopes. • A telescope consists of a gas detector, a silicon detector, and a cesium iodide detector. • A super telescope consists of a gas detector, two silicon detectors, and a cesium iodide detector. • These are arranged in a 4π or spherical arrangement. • This is good for central, intermediate energy collisions. It is also efficient at detecting heavy residues.

5. Super Telescope Detector

6. NIMROD Picture

7. Upgrade of NIMROD • Additional silicon detectors are being added in the forward beam direction to NIMROD • The addition consists of an additional ring from 45 to 90 degrees and a half sphere from the ISiS array. • The ISiS array also consists of telescopes (gas detector, silicon detector, and cesium iodide detector)

8. ISiS

9. Silicon Detectors • Silicon detectors are a PN junction. • The detectors need an electrical voltage to be applied in order to create a layer of depletion at the junction. • Why depletion is important? • What is leakage current? • As Radiation bombards these silicon detectors it becomes harder and harder to maintain the depletion layer.

10. Photodiode Detector • A silicon wafer that is used to capture light signals produced by radiation in cesium iodide detectors • This are used to collect the signals from the cesium iodide detectors of ISiS

11. What is a Bias Box? • Delivers positive or negative voltage. • between 0-255 volts • It can control up to 320 channels at one time • Can monitor leakage current and actual voltage on a silicon or photodiode type detector

12. Bias Box

13. Previous History • All silicon detectors have either there own individual high voltage supply modules or they were controlled by a box which set multiple silicon but each silicon had to be set by hand or “dialed up”. • It also monitored leakage current but an experimentalists had to be inside the cave to monitor the values, which means loss of beam time about ($750/hr).

14. Why make a Bias Box GUI? • We need to be able to remotely- • Bias all channels at once • Set all channels to zero at once • Bias a single silicon • Monitor the voltages and leakage currents • Load voltages from a file and save voltages to file • Change a voltage array file conveniently • Automatically ramp the voltage up and down

15. The Bias Box GUI

16. Bias Box GUI Picture #2

17. Bias Box GUI Picture #3

18. Connecting the components • The Bias Box- • To add voltage to the silicon through the controller board • Connect to an Analog to Digital Converter (ADC) for monitoring the voltages and currents. • The Controller Board- • The NIMROD silicon detector is managed by a controller board on the outside of the ring. • The controller board delivers voltage to the silicon. • It pre-amplifies the analog signals produced by the silicon. • Then passes the amplified signal to another amplifier • Path of The Signal- • After the amplifier the signal then goes to an ADC which passes the signal to the computer • Afterwards a graph is produced from the energy loss between the ion chamber and the silicon; from which particle identification can be done.

19. Controller Board

20. Summary • User Interface program was designed with the intent of monitoring voltage and current while biasing to NIMROD’s detectors remotely, including the new addition of ISiS, a spherical particle detector. • The program takes user input values and sends Biasing voltages to NIMROD’s silicon detectors. The GUI also monitors the actual charge held in the detectors of a specified silicon, and the leakage current on a specific silicon.

21. Acknowledgements • The National Science Foundation • The Department of Energy • SJY Group- • Dr. Sherry Yennello, Sara Wuenschel, August Keksis, Zach Kohley, Brian Stein, Sarah Soisson, George Souliotis, and Dinesh Shetty. • Thank You for your attention • Thank You REU Program at Texas A & M University