CHIPS Run Feb-2008

From New IAC Wiki
Revision as of 23:18, 26 February 2008 by Oborn (talk | contribs) (→‎16:00:)
Jump to navigation Jump to search


Configure 25 Mev Beam line

NaI Detector

PMT HV 1500 Co-60 1microCi source: 1MeV band at about 55mV
Co60 NaI 1500HV.jpg

PMT HV 1500 no source, noisey tube
Background NaI 1500HV.png

Beam Profile

1.5 inch FWHM beam profile measured at 8 mA peak current. The units on the beam scan is in inches. so the grid is 2inch by 2 inch (5cm by 5cm). Frequency is 60 Hz.

BeamProfile 2-26-08 1.jpg

_________________________________ 4 mA peak current

400 px


400 px

Beam on


Turned beam on zero degree port and NaI lights up whan positioned just after the beam pipe window.

Must be gammas Rate = 10 count/sec. Anode amplified (x64) then discriminated and put into a scaler. Threshold on discriminator is 2 Volts and results in zero counts when beam off. NaI PMT at 1500 volts.

NaI Pulse 2-24-08.png


Now move NaI detector so it is near experimental Cell wall. Just inside the wall

Gamma rate goes to zero!

NaI Pulse 2-24-08 1.png

Now change scope to 5 sec accumulation. 1 Mev electron should give 55 mV pulse on scope.


Now try to put electrons into Experimental cell.

We turned on the first dipole to deflect 10 MeV electrons onto the Tungsten target. The quads between the two dipoles were used to minimize the rates on the NaI. Then we turned on the last dipole to deflect 3 MeV electrons into the Experimental cell. And measured the following rates

811/15 sec threshold at a minimim

NaI Pulse 2-24-08 3.png

Now insert 1.2 cm thick Aluminum plate in front of the NaI in order to capture all the electrons and measure the gamma rate.

776/15 sec threshold at a minimim

400 px