# THHΘR Cosmic Ray Sensor

## Sensor

CHAOS Jr: HET BGO and 2× HETB. 
- BGO: 2 photodiodes × 2 gains = 4 channels
- HETB: 2 detector × 2 segments × 2 gains = 8 channels

## Electronics

- single 5…20V power supply
- 37 pin Omnetics Bilobe connector to the preamps board, A28200-037
- detector bias voltage, positive or negative
- 12 channel DORN readout, dual gain (with six preamps)
- with Beau-SK type preamps
- 10LC25 FPGA
- ATtiny824-XF 
- AT45B161E for FPGA bitfile and data
- 3.3V UART (optional RS485 half duplex) ifc to OBC
- optional HSS serial ifc/spacewire.
- optional MS5534 pressure sensor for balloon missions
![Layout](thhor_crs-topbot.png)

### Transformer

- 4 turns, thick, Vcore, 1.25V, directly regulated.
- 12 turns, thick, primary.
- 12 turns, medium, SEPIC, 4.5V digital, LDO regulators Vpll=2.5V, Vio=3.3V, Vadc=3.3V.
- 19 turns, medium, +7.5V, LDO regulators +5V shaper, preamps, fets.
- 19 turns, medium, -7.5V, LDO regulators -5V shaper, preamps.
- 19 turns, thin, Vbias cascade.

![Transformer](IMG_20260324_100529_131-1200.jpg)

## Charge Sensitive Amplifier

![Layout](thhor_csa-topbot.png)