The ProtoDUNE -SP Cosmic Ray Tagger (CRT) consists of 32 scintillator modules originally developed for the Double Chooz experiment. Groups of 4 modules are mounted in a frame, and pairs of frames are organized into USB streams for readout. So, the CRT has 4 USB streams, each of which is responsible for reading out 8 modules.

Default Board Reader to USB Stream Mapping

A Board Reader is an (art-) DAQ process that converts the backend data from a USB stream into Fragments for trigger matching and offline processing.

Board Reader Name USB Stream Position
crt0 13 US beam left (Jura)
crt2 14 US beam right (Saleve)
crt1 3 DS top
crt3 22 DS bottom

The CRT Rack

The CRT rack can be found DAQ side, about where the clean room ends. The main components of the CRT rack are the following: timing system (1), LVDS to NIM converter (2), scalar (3), low voltage power supply (4), high voltage power supply (5), CRT network computer (6).

If you need to power cycle because of this* instance, please see Power Cycling the CRT


Timing System

The timing system, aka the timing endpoint, sends the CRT our clock and sync signals. If the CRT timing endpoint isn't working, then the timing system isn't working. If you have issues with the timing endpoint and have followed the CrtTroubleshooting instructions on reseting it, then it is best if you contact timing system experts.

LVDS to NIM converter and Scalar

From the timing system we get LVDS signal, which then needs to be converted to a NIM signal. Clock out is 50MHz, and if there is ever uncertainty whether or not we are receiving clock this can be checked at the Double Chooz module with an oscilliscope. The NIM signal from clock and sync then go in to the Scalar/Timer


Low Voltage Power Supply

The low voltage power supply provides voltage to the PMT boards on each module. There are a few things to be aware of when it comes to the LV. Usually the LV is on but the screen does not light up. In order to make sure the LV is on, simply press one of the up or down arrows on the module.


As seen in the picture, there are two LV modules. The bottom module, NP04-CRT-02, has four channels. Channel 1 is the fan out and should be set to 6.1V and drawing around 2.11A. Channel 2, Channel 3 are voltage supplies for 1/2 the PMT boards and should be set to 6.3V drawing around 2.49A. Sometimes the current is +- 0.03A but any bigger of a difference in current is reason for concern. If you see a large difference in the current values (+-0.10A), please turn off the LV as this might be a damaged hardware problem. If this is the case contact the CrtExperts and see BringingCRTUpFromRackOff. Channel 4 is for the USB and should be around 5V and 0.55A. The top module, NP04-CRT-01, contains the voltage supply for the remaining PMT boards. Channel 1 and 2 should both be around 6.4V and 2.5A.

High Voltage

At this point the HV is not integrated into a framework where you can easily adjust it. Instead in order to check on the HV you need to go to the laptop beside the CRT rack and open it up. The system you want is Geco, and the program icon can be found on the desktop. If something bad happened to the HV, then the system is set up to trip so that the hardware is not damaged. If the channels from 03.000 to 03.031 are green, then the HV is ok. If the channels are highlighted in red then that means the system was tripped. In the case of red channels the best course of action would be to turn off the LV, directions found in steps 1-8 on PowerCyclingCRT and contact the CRT experts.

CRT Network

This allows us to connect to the CRT computer (ssh np04daq@np04-crt-001). If you need to connect to the CRT computer and cannot, make sure that the power is on. If the power is off, then it is possible somehow we lost power to the entire rack. Check if the HV channels are red and if the voltages and currents on the LV channels are what you would expect. If not then see BringingCRTUpFromRackOff.

-- Main.anolivie - 2018-11-02

--Main.SarahMarieHenry - 2018-11-12

Topic attachments
I Attachment History Action Size Date Who Comment
PDFpdf CRT_Geometry_Documentation_v2.pdf r1 manage 2347.4 K 2018-11-02 - 16:04 AndrewPaulOlivier  
JPEGjpg CRT_Rack.JPG r1 manage 2319.2 K 2018-11-12 - 11:34 SarahMarieHenry  
JPEGjpg IMG_3135.JPG r1 manage 2381.1 K 2018-11-12 - 11:27 SarahMarieHenry  
JPEGjpg IMG_3135_2.JPG r2 r1 manage 2408.5 K 2018-11-12 - 11:51 SarahMarieHenry  
JPEGjpg IMG_3138.JPG r1 manage 2352.7 K 2018-11-13 - 16:27 SarahMarieHenry  
JPEGjpg IMG_3140.JPG r1 manage 1934.5 K 2018-11-12 - 12:04 SarahMarieHenry LV voltage and current
JPEGjpg IMG_3143.JPG r1 manage 2924.3 K 2018-11-12 - 16:21 SarahMarieHenry  
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Topic revision: r6 - 2018-11-13 - SarahMarieHenry
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