Documentation

NLCTA Proposal: version 1 2

Slides from Takashi on checking Gaussian approximation with EGS simulation - link

Collimator scattering at JLab - link

Pre-NLCTA beam test slides from Pelle - link

Summary of results from beam test from Pelle - link

Sensor probing results in lab - link

Calibration and lab tests after pulling wirebonds from Omar - link

Simulation of beam parameters

Beam loss scenario with silicon edge hit

Intensity "per strip" (60um wide bands): 150um or 500um sigma beam spot, 50um or 500um Be exit window, 10cm or 30cm downstream of exit, Air included

10pC:

100pC:

Beam spot for one of them as example:

Beam loss scenario with direct hit

Beam parameters - 500um beam spot - 177cm & 6 foils

Beam parameters - 500um beam spot

Beam parameters - 150um beam spot

Data

NLCTA runs:

/u1/software/daq/baseline_XpC_YF_ZV_HHMM.bin

X: bunch charge, Y:# foils, HHMM: time

Data taken post NLCTA in group C with same setup (cables, supplies, etc.):

Baselines:
/u1/software/daq/baseline_*V_lab_postbeam/_2/_3.bin

Calibration:
180V bias: /u1/data/SVT2014/half_module/gimp_lab_postnlcta/1/
220V bias: /u1/data/SVT2014/half_module/gimp_lab_postnlcta/2/

Log book

10/2/13

We observed that there was a new channel that had high noise after installation. It was not there during test with the source. Could be dust or a real pin hole

PLOTS OF SOURCE TESTING AND THE BASELINE RUN FROM MONDAY AT 180V

10:10
Module fully installed but powered off. Out sensor is ~177cm from the exit window.
Mike setting up electron gun; some tuning is needed on the beam line since last experiment ran at 60MeV instead of 120MeV.

Noise before beam:

10:30
Beam E=119.3MeV, 50pC at gun, 10Hz
Start with 0 foils in order to search for the beam on the insertable phosphor screen.
The Phosphor screen is at ~75cm from exit window.
We use the measured voltage on the toroid located downstream of the spectrometer magnet: "ADC1".
At this point ADC1=0.06V which is ~40pC according to Mike.

10:37
Move in foils one by one and observe beam spot on phosphor screen. Picture and extracted spot size at each thickness can be seen below. The screen is about 75cm downstream of the exit window.

10:49
Lower bunch charge.
Insert 6 foils.
Still possible to see the beam on the phosphor screen but barely.
Mike estimates this to be order of 1fC/bunch.

10:55
Trying to time in readout using external trigger. Observe strange very large signals that went away after restart of daq. The disconnected APV got occassional hits at 0 ADC? This seemed to happen a few times even after we disabled it in the configuration. Is that possible even? We kept it disabled as it screwed up the scale.
We stepped through the latency setting from 130->5 with no sign of signal.
The linac had tripped so we don't know if we could have seen anything.

11:10
Linac back again.
10Hz, 120MeV, ~fC (estimation)
180V bias, see a ~10uA leakage current. This doesn't chance when beam goes on/off.
We observe large, ~400ADC, sample to sample shifts when using external trigger.
When beam is turned off we still see ~100ADC sample to sample shifts.
Everything looks ok with software trigger with beam on/off.
We turned off the RF equipment (X- and S) in the tunnel and that brought the noise back to 35-40ADC. Looks like there was some interference. There are many things that are exposed: 5m long power, incl. bias, wires running along floor, devboard on floor 1m below beam line and ~1m from dump. This only happened on external trigger and due to time constraints we decided to go on with our program and forget about timing in.
PLOTS OF SHIFTS FOR THE DIFFERENT CONDITIONS

11:36
Starting radiation program. There was no way we could measure anything below ~1pC so we start the program from there:

• Start with 6 foils
• Beam energy: 120MeV, 10Hz, bunch charge 1pC
• Start at 180V bias voltage on sensor
• 30s-60s of exposure to beam at each setting of bias voltage and bunch charge
• Run baseline at each setting and a baseline at 180V for each setting to be able to compare.
• Wrote down the measured leakage current from the bias supply. It takes quite some time for it to settle so the measured values fluctuates a lot. After many runs the 180V leakage was consistently at 5uA every time we came back to it.

Runs taken, all at 6 foils:

11:36
Everything looks ok for 1pC setting.

Baseline taken at 180V, after irradiating with 1 pC at 180V:

Baseline taken at 250V, after irradiating with 1 pC at 250V:

Baseline taken at 180V, after irradiating with 1 pC at 250V:

Baseline taken at 350V, after irradiating with 1 pC at 350V:

Baseline taken at 180V, after irradiating with 1 pC at 350V:

Baseline taken at 400V, after irradiating with 1 pC at 400V:

Baseline taken at 180V, after irradiating with 1 pC at 400V:

Baseline taken at 450V, after irradiating with 1 pC at 450V:

Baseline taken at 180V, after irradiating with 1 pC at 450V:

Baseline taken at 500V, after irradiating with 1 pC at 500V:

Baseline taken at 180V, after irradiating with 1 pC at 500V:

12:00
At 10pC and 500V we observed a channel with x3 higher noise in the "weird" apv chip which looked like a pinhole candidate. However, it seem to go away with lower bias voltage.
We observe a previously unseen step in the noise from 30 to 35 ADC in the middle of both working APV25. This step was turning on over a couple of channels. Not sure what this is.

Baseline taken at 180V, after irradiating with 10 pC at 180V:

Baseline taken at 350V, after irradiating with 10 pC at 350V:

Baseline taken at 180V, after irradiating with 10 pC at 350V:

Baseline taken at 500V, after irradiating with 10 pC at 500V:

Baseline taken at 180V, after irradiating with 10 pC at 500V:

12:15
Continue to 100pC and 180V.
Here we see a drastic change and what looks like many shorts has developed across the sensors. We don't see any case where the channel get a larger noise but they all go down to a level of about 20ADC.
The step in noise also become worse.

12:30
At 100pC and 350V.
Here we see a large increase in number of channels that are "shorted".
Interesting it seems like the behavior depends very sharply on the bias voltage setting. If we go to 210V the shorts are less pronounced but spike up above 215.
We don't see any real changes on the leakage current.

Since we'd like to keep some channels alive we stop at this point.

Baseline taken at 180V, after irradiating with 100 pC at 180V:

Baseline taken at 250V, after irradiating with 100 pC at 250V:

Baseline taken at 180V, after irradiating with 100 pC at 250V:

Baseline taken at 350V, after irradiating with 100 pC at 350V:

Baseline taken at 180V, after irradiating with 100 pC at 350V:

10/3/13

Baseline taken at 180V in group C:

Operation

DAQ Desktop Setup

IP address: 172.27.244.72

ttyS0: ibootbar
ttyUSB0: BK
ttyUSB1: keithley

Power Supply Operation

dataprobe iBootbar

Manual

1. old three-output
2. BK
3. keithley
4. PC
5. monitor

Serial: 115200 8N1

Common commands:
"get outlets" - list all outlets
"get outlet X" - list outlet X
"set outlet X on/off/cycle" - turn on/off/cycle outlet list outlet X

Keithley 2400

Manual
Serial: 9600 8N1

Common commands:
"measure?" - returns [voltage, current, ]
"source:voltage?" - returns voltage
"source:voltage 10" - set to 10 V
"output on" - output on
"output?" - returns 1 for on, 0 for off
"source:voltage:range up/down" - change range for voltage setting

BK Precision 1697

Manual
Serial:

Common commands:
"SOUT000" - enable output
"SOUT001" - disable output
"VOLT00XY.Z" - sets voltage to XY.Z Volts

Pictures

Lab prep

GIMP current vs bias

460V-5.2uA (minutes to get down that low and still decreasing)
500V-5.7uA-3.6uA (20mins)