Observe c. 2mV p to p noise with DSO ( Z_in = 50 Ohm ) c. 60us period with HF structure. DSO connected to junction box via 34-way IDC - 16x Lemo-00 adaptor.

Origin of noise upstream of 4x34-way to 8x16-way Junction Box. Not microphonics from Edwards RV5 Rotary Pump.
No change observed with simple ground connections between NIM bin/+/-15V PSU/Junction Box and MSL type W1 preamplifier units/vacuum chamber/support assembly.


Estimate of electronic noise

Pulser BNC PB-5

Amplitude 0.5V
Attenuation x1
Decay time 1ms
Frequency 50Hz

Preamplifier RAL108
Output impedance 100 Ohm
Sensitivity 20mV/MeV ( into high Z load ), 6.7mV/MeV ( into 50 Ohm load ) 

Amplifier EG&G Ortec 571
Input terminated by 50 Ohm
Gain x1 (internal) x 1.0 (fine gain) x 50 (coarse gain ) = 50
Shaping time 0.5us

MCA Amptek 8000D
Input FSR 10V
12 bit ADC


Nominal gain = 6.7mV/MeV x 50 = 335mV/MeV

12 bit ADC input FSR = 10V / 0.335V/MeV = 29.85MeV FSR or 7.3keV/channel


dE p+n junction strip # 4 ( of 0-15 )

pulser peak centroid = 799.8 ch
pulser peak width = 7.8 ch FWHM = 57 keV FWHM


E p+n junction strip # 4 ( of 0-15 )

pulser peak centroid = 864.8ch
pulser peak width = 3.5 ch FWHM = 26 keV FWHM


E n+n Ohmic strip # 4 ( of 0-15 )

pulser peak centroid = 913.0 ch
pulser peak width = 5.3 ch FWHM = 39 keV FWHM


Noise estimates are probably accurate to c. 10% level.

Check RAL108 +/-15V PSU

Measured output voltages +15.21V -15.18V - OK

Observe output voltages with DSO ( ch #1 AC/1M +15V, ch #2 AC/1M -15V ) - see attachments 1 & 2

What we should observe is c. 1mV rms ( white ) noise but we clearly observe similar noise transients ( c. 60us period with HF structure ) to those observed at RAL108 
outputs. The RAL108 preamplifier units do have RC filters on the +/-15V - typically c. 100 Ohm and 4.7uF. Some additional, inline filtering with a lower rolloff 
frequency may be required.

> 
> Observe c. 2mV p to p noise with DSO ( Z_in = 50 Ohm ) c. 60us period with HF structure. DSO connected to junction box via 34-way IDC - 16x Lemo-00 adaptor.
> 
> Origin of noise upstream of 4x34-way to 8x16-way Junction Box. Not microphonics from Edwards RV5 Rotary Pump.
> No change observed with simple ground connections between NIM bin/+/-15V PSU/Junction Box and MSL type W1 preamplifier units/vacuum chamber/support assembly.
> 
> 
> Estimate of electronic noise
> 
> Pulser BNC PB-5
> 
> Amplitude 0.5V
> Attenuation x1
> Decay time 1ms
> Frequency 50Hz
> 
> Preamplifier RAL108
> Output impedance 100 Ohm
> Sensitivity 20mV/MeV ( into high Z load ), 6.7mV/MeV ( into 50 Ohm load ) 
> 
> Amplifier EG&G Ortec 571
> Input terminated by 50 Ohm
> Gain x1 (internal) x 1.0 (fine gain) x 50 (coarse gain ) = 50
> Shaping time 0.5us
> 
> MCA Amptek 8000D
> Input FSR 10V
> 12 bit ADC
> 
> 
> Nominal gain = 6.7mV/MeV x 50 = 335mV/MeV
> 
> 12 bit ADC input FSR = 10V / 0.335V/MeV = 29.85MeV FSR or 7.3keV/channel
> 
> 
> dE p+n junction strip # 4 ( of 0-15 )
> 
> pulser peak centroid = 799.8 ch
> pulser peak width = 7.8 ch FWHM = 57 keV FWHM
> 
> 
> E p+n junction strip # 4 ( of 0-15 )
> 
> pulser peak centroid = 864.8ch
> pulser peak width = 3.5 ch FWHM = 26 keV FWHM
> 
> 
> E n+n Ohmic strip # 4 ( of 0-15 )
> 
> pulser peak centroid = 913.0 ch
> pulser peak width = 5.3 ch FWHM = 39 keV FWHM
> 
> 
> Noise estimates are probably accurate to c. 10% level.

Processed scans of both sides of the Li target showing the beam spot, and an image showing what it looks like to the eye.

Phtotos of the front & back of the Al target and what it looked like once mounted and in the chamber.

Gafchromics foil was mounted on empty brass frame back to back with Li sample

Neutron beam goes well through the sample. Centered ~1 cm from sample center. Conclusion: no changes needed (too risky to make it worse and it is ok now)

dE Detector: W1-20 3186-9 20 um

E Detector: W1-150 3458-4 144 um

Voltages and Leakage Currents:

dE: 6 V, 0.02 muA

E: 50 V, 0.05 muA

MSL type W1(SS)-20

3186-9  20um Depletion voltage 3V Operating voltage 6V
3585-12 20um Depletion voltage 2V Operating voltage 4V

MSL type W1(DS)-150

3458-1 157um Depletion voltage 22V Operating voltage 52V
3458-4 144um Depletion voltage 18V Operating voltage 48V

• Start 9th August, access to EAR-2 11 am earliest but can start in rack area before
• Setup to be used: 1 dE (16 strips, 20 um thickness) + 1 E (16x16 strips, 150 um thickness. We have a spare for each thickness
• Sample and detectors to be mounted on the same flange

Things to check:

• alignment with beam centre (lasers and/or gafchromics foils)
• is the setup stable to knockes, can all detector / sample positions be well reproduced when making changes

Once setup us completed:

• checks with pulser
• mounf LiF sample number 3 and run with neutron beam
• check that all strips have signals
• confirm shape of gamma flash and that short times can be anaysed in both detectors (~1.8 us after flash)

If everything working:

• measure LiF-3 and the switch to Al-26
• towards end of the run we can also measure B-3 and the empty brass frame (Frame without mylar)
• proton statistics: 1E17 LiF-3, 1F17 B-3, ~3E17 Empty, 5.5 E18 Al-26

Travel times

Nick: 8-16, Annie 8-12, Tom, 7 -?, Claudia, 8-10, Emmanuel asap until end of run

Measurement runs until Octover 2nd. Disassembly by Nick and Emmanuel.

additional trips during the measurement as required (if something breaks/fails etc. )

Attached: photos of previous setup

TO Do: MCA availability at nTOF for quick noise checks (Nick)

            how many  channels in 14 bit, how many 12 bit (Nick)

          depletion voltages   for detectors (Tom)

          Register the eqipment at CERN as Edinburgh property (Claudia)

Box 1

1. RC412 Cables

2. Screws and parts for rails

3. Small rails

Box 2

1. Vacuum valves

2. IDC cables

Box 3 (Detectors)

1. WI-20

3186-9

2. WI-150

3458-4

3. WI-150

3458-1

Box 4 (Detector)

1. WI-20

3485-12

*List

**We also have the tube for the long rails

21:15 Changed from detectors in-beam to boron-10 sample 3 in-beam (in-beam measurement got 1000 triggers, 500 of which were dedicated). The sample was mounted identically to LiF 3. An attempt was made to replace the 20-micron dE detector with a 50-micron one, but the screwholes on the 50-micron detector did not match the 300-micron E-detector ones and therefore could not be mounted. 20-micron detector was therefore re-attached. Planning to run for 12 hours with boron than dismount.

After long beam-off, changed detector mount by moving it 2 cm forward into the beam, after removing LiF 3.

Increased detector-target (LiF 3) separation by 1.5 cm. Had to replace the support strut under the detectors due to the previous one being fuly retracted even for minimal target-detector separation. This change may affect detector rotation relative to the target.

DEED 6 and 9 no signal throughout the campaign.

EFED 27 high oscillations in baseline throughout the campaign.

The pulser has been switched from triggering from beam trigger to running at a 10 Hz rate, and will now appear in random places in signal traces. Planned to run overnight measuring LiF3, switch to empty + detector in beam in the morning.