TO DO list:

- JOSHY time schedule and task interest

- funding (Vasa, SSC)

- ion concept discussions - Spanel, Svoboda, UTEF...

- STANDARD radiosonde detailed info from LEBEDEV inst.

industrialPC-uComp interface

pending decision about:

incorporating reset function into uControler having two separate ETH interfaces through E-link, 

OR

using single ETH on indPC, uControler connected to serial to it (indPC) WITH TESTED WATCHDOG function

Project Planning

PDR documents sent out

CRIndIons SED and PDR presentation sent to ESA.

3D model

updated version

ESRANGE provided battery source confirmed

A 28V/1A battery power will be supplied to each experiment if needed. The experiment

must have a 4 Pin connector type MIL – C-26482P series 1, placed on the outside of the

structure / housing.

If the experimenter chooses to use some other electrical system or batteries, it has to be

discussed with the BEXUS project manager before the critical design review (CDR).

Breakdown voltage environmental dependences

From easy calculations based on Paschen's law (i.e. WIKI) 5.7mm is the optimal effective distance of our spark-plug electrodes to obtain best results having available just max 800V potential. 

This graph is for parallel electrodes separated by 2.5cm. Find on figure for air 1 torr=133.3Pa) expected lowest pressure during flight will be ~ 0.1 Torr so well in our range. Max (ground) pressure ~700 Torr so we can effectively operate from on almost whole range with optimal 5.7mm distanceand from ~10km up higher even with 2.5cm distant electrodes.

More interesting, dependences on temperature and humidity as well> http://home.earthlink.net/~jimlux/hv/paschen.htm

Vbreakdown = 24.22 * x + 6.08 * SQRT(x)

 x = 293 * p * d / (760 * T)

p = pressure in Torr (mm Hg), d = distance in cm, T = Temperature in Kelvins, Vbreakdown in kV

Aluminum profiles

http://www.betz.cz/download_soubory/Hlinikove_profily_Bosch_12.pdf
http://www.betz.cz/download/soubory_ke_stazeni.html

3D Model

I just render this image.

Risk Management

analysis was done and sent for comments.

Electrical Design CHapter

was written and distributed for comments.

Update of HV source

Micro Controller

Micro controller unit was designed

Supply: 5V@2mA
40MHz clock ~10MIPS
RS232 interface
Humidity sensor input
1 dig input
2 dig outputs

Complete Spark Detection Circuit

Output TTL pulse duration is ~110 ms

Logo

by Jitka

Spark Detection Circuit

Spark Detection Circuit was designed and simulated
RED trace: Output signal
GREEN trace: Spark plug voltage

Required supply voltage is +5V.

Safety charge is 50uC. It's 50uF @ 1000V => 10nF @ 800 V SAFE ENOUGH

There will be a shaping 555 circuit that wasn't simulated.

Ionisation tube

Concept of Ionisation tube and EMC.

Ionisation tube will be an independent module with double shielding. It will have it's own battery power source and all digital I/Os will be insulateted by the ADuM11001. It is a digital isolator based on Analog Devices iCoupler technology. Combining high speed CMOS and monolithic air core transformer technology, this isolation component provides outstanding performance characteristics superior to alternatives, such as optocoupler devices.
The spark plug will be out of the gondola.

#It's a question, where to place the humidity sensor. It should NOT be inside of the Ion. tube, but it can be mounted on it (outside the double shielding).

5V switching power supplies

we still have 2 PCBs for the 5V/2A PS and and can be used for new power supplies. I suggest to use both of them in parallel for back up.

Thermal scan of the TimePix

The thermal camera cannot be moved from the CTU. We have to move the TimePix to my office. Waiting for approve from the IAP.

New chapter for the SED

abut the thermal design was written and distributed for comments.

Thermal scan

HV Power source

HV source was designed and simulated. HV is ~900V (stabilized and adjustable).