Posts by jhelebrant

11) Message boards : Science : Detector locations to avoid, to prevent a biased reading? (Message 1869)
Posted 3932 days ago by Profile jhelebrant
the smoke detectors contain very small amount of Americium-241 so its activity is around 37 000 Bq, according to this source:
http://www.world-nuclear.org/info/Non-Power-Nuclear-Applications/Radioisotopes/Smoke-Detectors-and-Americium/#.Udv7cpzYeqs

only 0.3 micrograms. They also say:

Am-241 emits low energy gamma rays of 60 keV. The Am-241 gamma dose constant of 3.14 mSv/hr at a distance of one metre from a certain amount - 37 GBq - of Am-241. This gives an annual dose at one metre of 27 µSv/yr for an average household smoke detector – around 100 times lower than the dose from natural background radiation.


However,
we have here a few those elements from smoke detectors in total activity about 75 000 Bq so I did a practical test with our portable detector:
https://www.saic.com/products/security/pdf/gr-135_30Jun10.pdf

In direct contact I got values about 0.5 microSv/h but in 1 meter distance there was nothing - I measured normal background.

So I would say if the smoke detector is on the ceiling then you do not have to worry about it. :-)
12) Message boards : Science : Data analysis - What can you really measure? (Message 1868)
Posted 3932 days ago by Profile jhelebrant
Hi Jason,
not sure if I fully understand what you mean. However, there is it not averaging - you always have pulse count for certain time interval:

sample_ID,host_ID,pulse_count,date_time,Y_coord,x_coord,sample_time,type,experimental,version
45032963,1934,9,2012-06-29 14:16:47,50.037849,14.482327,0.721,n,0,594
45037617,1934,15,2012-06-29 14:17:29,50.037849,14.482327,0.702,n,0,594
45037618,1934,18,2012-06-29 14:18:11,50.037849,14.482327,0.697,n,0,594
45037619,1934,18,2012-06-29 14:18:52,50.037849,14.482327,0.694,n,0,594

Apart from the mentioned data traffic reason there is also another one. As I know, this network was built to provide independent and volunteer radiation monitoring and warning system (although in case of some alarm from such network you should contact institutions responsible for radiation protection or police/fire fighters first).

If you use short time interval to calculate the dose rate (usually microGrays or microSieverts per hour) with low sensitivity small geiger tubes (the SBM-20 have lower sensitivity to background values), then your dose rate values varies much - you can see it on older data. If you collect counts for too short period you have too less data to calculate the dose rate "reasonably accurately". And be sure, that most radiation warning sensor networks use 10 minutes and longer intervals not because of the data traffic.

Finally, I do not think there is a reason to have recorded each count + time value. Using 4 minutes interval to collect counts and also to calculate the dose rate can reduce false trends in data.
13) Message boards : Science : Detector behavior in high dose rate levels (Message 1717)
Posted 4000 days ago by Profile jhelebrant
Thanks for suggestion. I moved the source to the other side and the results are much better.



Okay, there are some differences in results, but according to my colleague even a small difference in distance has a big influence in this case.

However, very positive and important result for us is that the detector does not have problems with measuring such high dose rates.



We already tested some other sensors (but with the same GM tube) and they had problems.
14) Message boards : Cafe : Problem with detector on linux (Message 1713)
Posted 4003 days ago by Profile jhelebrant
Hi,
I am trying to get one of my detector working on linux. First I had problem with the Error 417, which I solved using the cc_config.xml file in /home/jan_helebrant/BOINC:


<cc_config>
<options>
<http_1_0>1</http_1_0>
</options>
</cc_config>


However, I still do not send any data to the server and still see 0% progress, although it looks to be ok:

Po 29. duben 2013, 14:43:43 CEST | | Starting BOINC client version 7.0.28 for i686-pc-linux-gnu
Po 29. duben 2013, 14:43:43 CEST | | log flags: file_xfer, sched_ops, task
Po 29. duben 2013, 14:43:43 CEST | | Libraries: libcurl/7.29.0 OpenSSL/1.0.1c zlib/1.2.7 libidn/1.25 librtmp/2.3
Po 29. duben 2013, 14:43:43 CEST | | Data directory: /home/jan_helebrant/BOINC
Po 29. duben 2013, 14:43:43 CEST | | Processor: 4 GenuineIntel Intel(R) Core(TM) i3 CPU M 350 @ 2.27GHz [Family 6 Model 37 Stepping 5]
Po 29. duben 2013, 14:43:43 CEST | | Processor: 3.00 MB cache
Po 29. duben 2013, 14:43:43 CEST | | Processor features: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx rdtscp lm constant_tsc arch_perfmon pebs bts xtopology nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm pcid sse4_1 sse4_2 popcnt lahf_lm arat dtherm tpr_shadow vnmi flexpriority ept vpid
Po 29. duben 2013, 14:43:43 CEST | | OS: Linux: 3.8.0-19-generic
Po 29. duben 2013, 14:43:43 CEST | | Memory: 1.84 GB physical, 3.90 GB virtual
Po 29. duben 2013, 14:43:43 CEST | | Disk: 82.64 GB total, 63.07 GB free
Po 29. duben 2013, 14:43:43 CEST | | Local time is UTC +2 hours
Po 29. duben 2013, 14:43:43 CEST | | No usable GPUs found
Po 29. duben 2013, 14:43:43 CEST | Radioactive@Home | URL http://radioactiveathome.org/boinc/; Computer ID not assigned yet; resource share 100
Po 29. duben 2013, 14:43:43 CEST | | No general preferences found - using defaults
Po 29. duben 2013, 14:43:43 CEST | | Preferences:
Po 29. duben 2013, 14:43:43 CEST | | max memory usage when active: 940.02MB
Po 29. duben 2013, 14:43:43 CEST | | max memory usage when idle: 1692.04MB
Po 29. duben 2013, 14:43:43 CEST | | max disk usage: 10.00GB
Po 29. duben 2013, 14:43:43 CEST | | don't use GPU while active
Po 29. duben 2013, 14:43:43 CEST | | suspend work if non-BOINC CPU load exceeds 25 %
Po 29. duben 2013, 14:43:43 CEST | | (to change preferences, visit the web site of an attached project, or select Preferences in the Manager)
Po 29. duben 2013, 14:43:43 CEST | | Not using a proxy
Po 29. duben 2013, 14:44:04 CEST | Radioactive@Home | update requested by user
Po 29. duben 2013, 14:44:08 CEST | Radioactive@Home | Sending scheduler request: Requested by user.
Po 29. duben 2013, 14:44:08 CEST | Radioactive@Home | Requesting new tasks for CPU
Po 29. duben 2013, 14:44:09 CEST | Radioactive@Home | Scheduler request completed: got 1 new tasks
Po 29. duben 2013, 14:44:09 CEST | Radioactive@Home | New computer location: work
Po 29. duben 2013, 14:44:11 CEST | Radioactive@Home | Started download of radac_1.73_i686-pc-linux-gnu__nci
Po 29. duben 2013, 14:44:11 CEST | Radioactive@Home | Started download of sensors_linux_1.73.xml
Po 29. duben 2013, 14:44:12 CEST | Radioactive@Home | Finished download of radac_1.73_i686-pc-linux-gnu__nci
Po 29. duben 2013, 14:44:12 CEST | Radioactive@Home | Finished download of sensors_linux_1.73.xml
Po 29. duben 2013, 14:44:12 CEST | Radioactive@Home | Starting task sample_1738013_0 using radac version 173 (nci) in slot 0


I also looked in /home/jan_helebrant/BOINC/slots/0 and found file stderr.txt containing many errors like this:

Radac $Rev: 560 $ starting...
Warning: cannot query manufacturer for device: error sending control message: Operation not permitted
Could not find any of the devices listed in sensors.xml: Device communication error
Warning: cannot query manufacturer for device: error sending control message: Operation not permitted
Warning: cannot query manufacturer for device: error sending control message: Operation not permitted
Warning: cannot query manufacturer for device: error sending control message: Operation not permitted
Warning: cannot query manufacturer for device: error sending control message: Operation not permitted[/quote]


I googled this thread and via Google Translate followed some advices but I have no idea what is wrong.

I can see the device correctly:
Bus 002 Device 005: ID 04d8:f6fe Microchip Technology, Inc.


and have the same also in sensors.xml:
<sensor>
<comment>3.01</comment>
<hardware_id>04d8:f6fe</hardware_id>
<revision>769</revision>
<revision_bcd>3.01</revision_bcd>
<vendor>microchip</vendor>
<product>radioactiveathome.org GRS</product>
<usb_protocol>1</usb_protocol>
<options>
<switch_gmsupply>1</switch_gmsupply>
<reset_counters>1</reset_counters>
<switch_buzzer>0</switch_buzzer>
<switch_backlight>0</switch_backlight>
</options>


Any idea what could be wrong? Thanks
15) Message boards : Science : Data analysis - What can you really measure? (Message 1708)
Posted 4007 days ago by Profile jhelebrant
Hi TJM,
we also wanted to recommend to increase the sampling time. Not only because of the database, but also for improving the measurement quality. In our sensor networks we mostly use 10 minute sampling interval which seems to be the best compromise for stationary measuring stations.

I played a little bit with the radioactive@home data from some selected stations and longer sampling interval decreases the value fluctuations very much.
16) Message boards : Science : Detector behavior in high dose rate levels (Message 1704)
Posted 4010 days ago by Profile jhelebrant
Hi,
we did some testing of the detector using 226Ra source (so called radium needle) with activity approx. 3.5 MBq. However the detector seems to show much smaller values:


link to better quality image

Are there any display limit for measurements or is the problem of electronics? As I know, the GM tube can measure up to miliSieverts per hour.

thanks

PS: going to continue in testing[/img]
17) Message boards : Number crunching : Is it possible to log data when in experimental mode? (Message 1691)
Posted 4016 days ago by Profile jhelebrant
hi,
we would like to test the detector behavior in higher dose rate levels. I have the detector set to experimental mode (of course) but would like to log the data somehow. We need them for further analyses.

As I know, those data are not saved in Radioactive@home database, so I need probably to catch them during sending or directly from the device.

I was able to identify the device using USB Device Viewer:

Device Descriptor:
bcdUSB: 0x0110
bDeviceClass: 0x00
bDeviceSubClass: 0x00
bDeviceProtocol: 0x00
bMaxPacketSize0: 0x08 (8)
idVendor: 0x04D8 (Microchip Technology Inc.)
idProduct: 0xF6FE
bcdDevice: 0x0301
iManufacturer: 0x01
0x0409: "microchip"
iProduct: 0x02
0x0409: "radioactiveathome.org GRS"
iSerialNumber: 0x00
bNumConfigurations: 0x01

ConnectionStatus: DeviceConnected
Current Config Value: 0x01
Device Bus Speed: Full
Device Address: 0x01
Open Pipes: 1

Endpoint Descriptor:
bEndpointAddress: 0x81 IN
Transfer Type: Interrupt
wMaxPacketSize: 0x0008 (8)
bInterval: 0x64

Configuration Descriptor:
wTotalLength: 0x0022
bNumInterfaces: 0x01
bConfigurationValue: 0x01
iConfiguration: 0x00
bmAttributes: 0x80 (Bus Powered )
MaxPower: 0x32 (100 Ma)

Interface Descriptor:
bInterfaceNumber: 0x00
bAlternateSetting: 0x00
bNumEndpoints: 0x01
bInterfaceClass: 0x03 (HID)
bInterfaceSubClass: 0x00
bInterfaceProtocol: 0x00
iInterface: 0x00

HID Descriptor:
bcdHID: 0x0101
bCountryCode: 0x00
bNumDescriptors: 0x01
bDescriptorType: 0x22
wDescriptorLength: 0x0016

Endpoint Descriptor:
bEndpointAddress: 0x81 IN
Transfer Type: Interrupt
wMaxPacketSize: 0x0008 (8)
bInterval: 0x64


and maybe I would be able to log it using something like SnoopyPro, but would be better if there is a more comfortable approach.

thanks
18) Message boards : News : About our HUGE delay... (Message 1645)
Posted 4066 days ago by Profile jhelebrant
In our case the order was only 2 detectors (ordered and paid in August 2012) - for testing (could be much more in future), but we would also appreciate some news in this case. It is not necessary to have detailed info about particular orders, but would be nice to know at least something like "we already shipped bunch of XYZ detectors and XY % paid during "some month" 2012 will be shipped this month."

thanks
19) Message boards : Science : detector testing with real radioactive sources (Message 1515)
Posted 4138 days ago by Profile jhelebrant
Hi guys,
when talking about testing with real sources, I can also help as I work in National radiation protection institute (SURO) in Prague, Czech Republic.

We ordered 2 detectors this August/September and we are going to perform a tests using various sources as soon as we will get them.

Currently we are testing slightly different Libelium Waspmote platform (almost based on Arduino) and in our case we were not able to measure more than about 120 microSv/h using the SBM-20, while with the Chinese J305 we were able to go to about 170 microSv/h.

You can see some of our results here.

Our colleague said that the SBM-20 is simply saturated and that we should have to apply some shielding to shift the measuring range to higher dose rate levels.

We want to try almost the same with radiactive@home detectors and we are very curious. :-)
20) Message boards : News : Orders confirmation email (Message 1513)
Posted 4139 days ago by Profile jhelebrant
Hi,
I got the email on 19. 8. 2012. Now it is 14.12. and detectors not here yet. I think I successfully confirmed the number of detectors (2) and the shipping address.

Now I am a little bit nervous if you have received the confirmation and the delay is caused by your technical problems and terrible workload at the end of the year or whether there is another problems on your or on my side.

Would be nice if you could let me know. If this is related with the general delay and I will know it, it is not problem for me. I just do not want to miss something.

regards

Jan


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