I have added the 0.5 version asm source code, released under the GPL: ftp://panteltje.com/pub/gm_pic/gm-0.5.ASM This code was assembled with gpasm-0.13.7 beta and I would not be a bit surprised if it did not assemble on MPlab.
Some comments on the code: Added an accumulated radiation dose counter, this is saved every minute in EEPROM if enabled via RS232. Added a dose alarm at 100 mR, when in alarm mode no ticks and LED flashes, then it is just a clock. Added a low battery warning message to the LCD, it comes in if the 9 V battery drops below 6.7 V. That voltage is determined by the 1.7 V dropout o the 78L05. The thing will keep working a bit below that, no auto switch off, deliberately. Added LCD backlight. All options can be configured via RS232. Logging via RS232 works too. Removed the frequency control for the HV generator, a bit too dangerous via RS232, change in the source if you need to.
I consider this project finished, at least for now.