IAC LeadFlourideCherenkovCrystalTests

Radiation exposure tests in December for Hall A.

We will have three days of beamtime (Dec 3-5). We will use the the 25-MeV linac to direct an electron beam upon the PbF2 crystals. The lead Flouride Crystals will be placed on a translator table so that each crystal can moved into the beam. The crystals are 30x30x185 mm^3 and are 1290g each.

We need to keep the Power below one 1 Watt onto the PbF2 crystal or 0.78 Gy/block. We can achieve this by setting the beam parameters of the 25-MeV LINAC (cf. http://www.iac.isu.edu/facilities/25MeV_hall.html).

Here we have: P = E * I [P] Watts, [E] MeV, and [I] uA

beam energy  20 MeV
Rep Rate:    10 Hz
I_peak:      50 mA/pulse
pulse width: 0.1 us (100 ns)

We find. Time on for one second is 1^{-5}s or 1 us. and Time off is 1 - 5us = 0.999999s The average current 0.999999 * 0 + 0.000001*50mA = 0.05 uA.

P = (20 MeV) * (0.05 uA) = 1 Watt.

With the proviso, that we wish to keep the I_peak (Instantaneous Current in the pulse) well above 5 mA so the it can be tracked by the pick-up coil. 50 mA/pulse will do the job.

Crew: Tony Forest, Adrianne Spilker, Amine Mestari, Syed Naeem, Pierre Bertin, and Phil Cole

Status of Setup.

 Translator Table (3 degrees of freedom).  
    Setup Done.  Amine and Adrianne
    DAQ/Readout
 Faraday Cups
    Setup
    DAQ/Readout
 Coil
    Setup 
    DAQ/Readout
 Lead Shielding
 

Translator table setup. o Day 1: 5 hours of beamtime

 1a) a first irradiation(blocks 1~4) ~5 hours Day 1
 2a) do a transparency measurement (blocks 1~4) ~3 hours Day 1
 3a) do a block (blocks 1~4) curing exposure to a blue light 24 hours day 1 day 

o Day 2: 5 hours of beamtime

 1b) a first irradiation(blocks 5~8) ~5 hours Day 2
 2b) do a transparency measurement (blocks 5~8) ~3 hours Day 2
 3b) do a block (blocks 5~8 curing exposure to a blue light 24 hours Day 2 and Day 3

o Day 3: 5 hours + 5 hours of beamtime.

 4a) repeat a transparency measurement (blocks 1~4) ~3hours day 3
 5a) do a second irradiation (blocks 1~4) ~5 hours day 3
 3a) do a transparency measurement (blocks 1~4) ~3 hours day 3
 4b) repeat a transparency measurement (blocks 5~8) ~3 hours day 3
 5b) do a second irradiation (blocks 5~8) ~5 hours day 3 at the end of the day

Day 4 and Day 5 will be used to more curing and transparency measurements.

The specifics are listed below RunPlan:

PbFl_RadTests-12-3-07

PbFl_RadTests-12-4-07

PbFl_RadTests-12-5-07

References:

NIM articles:

File:Achenbach NIM A416 1998 pg357.pdf

Private Communications

File:FEL IrradiationTests 8-25-07.pdf
File:TransmissionTestProcedure J.Roche 10-15-07.pdf
File:CalorimeterHeatingEquations.pdf