# HV burn in

Begin burn in after at least 3 volume changes.

Step 1: Set Voltage to 50 volts on all channels. Probe HVB to be sure that all sense, field, and guard wires have a voltage. (You should set current threshold to 10 microAmps on the HV supply)

Step 2: While monitoring the current, ramp the HV to the following

G:F:S= 525,-700,700

Step 3: Begin to take data recording the time and sense wire current as you ramp up the sense wire HV to 1400 volts while restricting the current draw to less than 10 micraAmps.

keep current under 10 micro amps while moving sense voltage up to 1400

# TDC cable test

The following table shows the data for TDC testing input channels using the best cable (looks the other cables were tested to choose the best one) that has the range (32-63), the cable does not a signal in the three channels: 32,35,47.

 Cable number range channels without hits

# Measured Sense wire output

## Cosmic Runs

### 3811

Cosmic rays were used to measure drift chamber time spectra with respect to scintillators placed above and below the drift chambers (more details are at the wiki location CLAS12R1_CosmicTestStand)

 Fig 23 from "The CLAS drift chamber system", M. Mestayer, et. al., NIM A, Volume 449, Issues 1–2, 11 July 2000, Pages 81–111 cosmic run from 1/10 - 1/14. Signal cable 4 (ch. 48-63). 16 channels with leading edge discriminators (-80 mV, 100 ns pulse width). Cosmics runs with lower discriminator thresholds Chamber 4 at JLab

# Cosmic measurements

CLAS6 Drift Chamber NIM paper

 Run # Date Description 3806 1/10/13 3 hour cosmic run, 16 channels with leading edge discriminators (-80 mV, 100 ns pulse width) 3809 1/10/13 cosmic run on 1/10. Signal cable 4 (ch. 48-63). 16 channels with leading edge discriminators (-80 mV, 100 ns pulse width). 3810 1/10/13 cosmic run from 1/10 - 1/14. Signal cable 4 (ch. 48-63). 16 channels with leading edge discriminators (-80 mV, 100 ns pulse width). Scintillator paddle F1/F2 on table above Sector 1, paddle I1/I2 below. 3811 1/10/13 3831 2/1/13 Changed disciminator from 80 mV to 60 mV, We improved the window, installed HV & STB boards, purged and started taking cosmic data again, DC is sandwhiched between 2 scints with PMTs aligned (PMT on only one end of Scint is turned on) 3833 2/4/13 Changed disciminator from 60 mV to 30 mV 3834 2/11/13 Changed disciminator from 30 mV to 60 mV 3835 2/19/13 Changed disciminator from 60 mV to 20 mV

(TDC1190[106]-TDC1190[104] = 3 ns) => PMT F1 - PMT I2 = Two PMTs that are on separate paddles and adjacent.

(TDC1190[106]-TDC1190[107] = 40 +/- 10 ns) => PMT F1 - PMT F2 = Two PMTs that are on the SAME paddle. Not sure why there is a 40 ns offset but the 10 ns wide range is because the paddles are about 70 cm long ( see CLAS12R1_CosmicTestStand#Scintillator_Timing_Studies)

 TDC-CH# WIRE 104 PMT I2 106 PMT F1 107 PMT F2 00 U1 L2W1 01 U2 L4W1 02 U3 L6W1 03 U4 L1W1 04 U5 L3W1 05 U6 L5W1 06 U7 L2W2 07 U8 L4W2 08 U9 L6W2 09 U10 L1W2 10 U11 L3W2 11 U12 L5W3 12 U13 L2W3 13 U14 L4W3 14 U15 L6W3 15 U16 L1W3 16 U17 L3W3 17 U18 L5W3 18? U19 L2W4 19 U20 L4W4 20 U21 L6W4 21 U22 L1W4 22 U23 L3W4 23 U24 L5W4 24 U25 L2W5 25 U26 L4W5 26 U27 L6W5 27 U28 L1W5 28 U29 L3W5 29 U30 L5W5 30 U31 L2W6 31 U32 L4W6 32 U33 L6W6 33 U34 L1W6 34 U35 L3W6 35 U36 L5W6 36 U37 L2W7 37 U38 L4W7 38 U39 L6W7 39 U40 L1W7 40 U41 L3W7 41 U42 L5W7 42 U43 L2W8 43 U44 L4W8 44 U45 L6W8 45 U46 L1W8 46 U47 L3W8 47 U48 L5W8 48 U49 L2W9 49 U50 L4W9 50 U51 L6W9 51 U52 L1W9 52 U53 L3W9 53 U54 L5W9 54 U55 L2W10 55 U56 L4W10 56 U57 L6W10 57 U58 L1W10 58 U59 L3W10 59 U60 L5W10 60 U61 L2W11 61 U62 L4W11 62 U63 L6W11 63 U64 L1W11 64 U65 L3W11 65 U66 L5W11 66 U67 L2W12 67 U68 L4W12 68 U69 L6W12 69 U70 L1W12 70 U71 L3W12 71 U72 L5W12 72 U73 L2W13 73 U74 L4W13 74 U75 L6W13 75 U76 L1W13 76 U77 L3W13 77 U78 L5W13 78 U79 L2W14 79 U80 L4W14 80 U81 L6W14 81 U82 L1W14 82 U83 L3W14 83 U84 L5W14 84 U85 L2W15 85 U86 L4W15 86 U87 L6W15 87 U88 L1W15 88 U89 L3W15 89 U90 L5W15 90 U91 L2W16 91 U92 L4W16 92 U93 L6W16 93 U94 L1W16 94 U95 L3W16 95 U96 L5W16

### Runlist Disc=30 mv

 4139 5/13/13 30 mv Threshold, S:F:G=1500:-750:550 CLAS12_r4139, run started at 9:05:57 on 5/13 and ended at 12:52:44 on 5/20

### Runlist Disc=58 mv

 4140 5/20/13 58 mv Threshold, S:F:G=1280:-750:550 CLAS12_r4140, run started at 13:57:34 on 5/20 and ended at 16:43:39 on 5/20 4141 5/20/13 58 mv Threshold, S:F:G=1500:-750:550 CLAS12_r4141, run started at 16:47:48 on 5/20 and ended , TDC channels 62->76 were failing after event 80000 and then seemed to turn on and off for a while 4142 5/20/13 58 mv Threshold, S:F:G=1500:-750:550 , run started at , TDC channels 62->76 were failing they seemed to turn on and off for a while 4143 5/27/13 58 mv Threshold, S:F:G=1500:-750:550 , swapped last two inputs to ADB board for channels 64->96. Check if hits start failing on ch 80->96 4145 5/28/13 58 mv Threshold, S:F:G=1500:-750:550 , swapped middle inputs between two ADC boards (ch 17->32 echanged with ch 64->80), all channels were working??? lets switch it back, perhaps connector had bad connection? 4146 5/29/13 58 mv Threshold, S:F:G=1500:-750:550 , everything connected back to order used in run 4142, run started at 08:12:35 on 5/29/13, ended at 07:39 on 6/10/13. 1,238,205 events , may have run low on ArC02 near the last day or two.

#### HV-vs- Efficiency

Keep the discriminator constant and change the HV.

The HV should stay at the ratios of S:F:G=1:0.5:4/11

The network will be down Thursday (6/20) night until Friday morning.  Stop the DAQ Thursday at 5pm


 Wire PostAmpOut (CH 1-96) TDC Channel L W 5 1 1 1 3 1 2 2 1 1 3 3 6 1 4 4 4 1 5 5 2 1 6 6 5 2 7 7 3 2 8 8 1 2 9 9 6 2 10 10 4 2 11 11 2 2 12 12 5 3 13 13 3 3 14 14 1 3 15 15 6 3 16 16 4 3 17 17 2 3 18 18 5 4 19 19 3 4 20 20 1 4 21 21 6 4 22 22 4 4 23 23 2 4 24 24 5 5 25 25 3 5 26 26 1 5 27 27 6 5 28 28 4 5 29 29 2 5 30 30 5 6 31 31 3 6 32 32 1 6 33 33 6 6 34 34 4 6 35 35 2 6 36 36 5 7 37 37 3 7 38 38 1 7 39 39 6 7 40 40 4 7 41 41 2 7 42 42 5 8 43 43 3 8 44 44 1 8 45 45 6 8 46 46 4 8 47 47 2 8 48 48 5 9 49 49 3 9 50 50 1 9 51 51 6 9 52 52 4 9 53 53 2 9 54 54 5 10 55 55 3 10 56 56 1 10 57 57 6 10 58 58 4 10 59 59 2 10 60 60 5 11 61 61 3 11 62 62 1 11 63 63 6 11 64 64 4 11 65 65 2 11 66 66 5 12 67 67 3 12 68 68 1 12 69 69 6 12 70 70 4 12 71 71 2 12 72 72 5 13 73 73 3 13 74 74 1 13 75 75 6 13 76 76 4 13 77 77 2 13 78 78 5 14 79 79 3 14 80 80 1 14 81 81 6 14 82 82 4 14 83 83 2 14 84 84 5 15 85 85 3 15 86 86 1 15 87 87 6 15 88 88 4 15 89 89 2 15 90 90 5 16 91 91 3 16 92 92 1 16 93 93 6 16 94 94 4 16 95 95 2 16 96 96

## Measurements with source

4/20/12 1hour counts:

SL2 HVB1 Column 18 Row 5

-With source 14459 pulses/1502 sec

4/23/12 SL1 HVB7 column 203 row 4

-With source 50681 pulses/3760 sec.

4/25/12 1 hour counts:

SL2 HVB4 Column 118 row 5

- Without source: 33145 pulses/3610 Sec.

- With source(CS-137):38262 pulses/3600 Sec.

- Without source: 37548 pulses/3715 Sec.

Preamp voltage:5V

## Background measurements

HV off 4/5/12 Background counts:

27 pulses/61806 Sec.

SL2 Column 132 row 2

Preamp voltage 6.3V

Discriminator threshold 46mV

Preamp on= 6.3

4/9/12: Back ground count measurements

4531 counts/69564 seconds

2044 counts/24620 seconds

4/10/12 Background counts:

3 pulses/ 74500 sec.

SL1 HVB7 Column 196 Row 2

Preamp voltage 6.3 V

Discriminator threshold 46mV

4/16/12 Background counts:

280 pulses/245850 sec

SL1 HVB7 column 226 row 2

preamp voltage 5V

Discriminator threshold 46mV

4/17/12 Background counts:

6 pulses/62407 sec

SL2 HVB7 column 226 row 8

preamp voltage 5V

discriminator threshold 46mV

4/20/12 Background counts:

63 pulses/ 71724 Sec.

SL1 HVB7 column 226 row 8

Preamp voltage 5V

Discriminator threshold 46mV

4/23/12 Background counts:

41078 pulse/ 245104 sec.

SL1 HVB7 Column 203 Row 4

Preamp voltage 5V

Discriminator threshold 46mV

## Cosmic measurements

4/24/12 Cosmic count:

SL1 HVB1 Column 3 Row 10

14534 pulses/11547 sec.

Preamp voltage 5V

4/26/12 Overnight Cosmic pulse count:

SL2 HVB4 Column 118 Row 5

53122 pulses/49793 Sec.

Preamp voltage 5V

# Primitive Tracking

## Linfit to layer -vs- y distance

The staggered layering of the cells in a single drift chamber super layer results in cells that are offset from each other by 30 degrees (PI/6). Below is a event illustrating the observation of ionization signals observed by 6 of the 96 instrumented wires caused by the passage of a cosmic ray.

A coordinate system is established which defines the X-direction along the depth of the superlayer and the Y-direction along the endplate of the chamber. The chamber is facing towards the sky so cosmic rays may enter the front face of a chamber. The location of the cells, with this coordinate system, may be determined using the equations below along with the row and column of the hit.

TDC2row[]={5,3,1,6,4,2};
x=TDC2row[TDCChannelNumber%6)];
y=(TDCChannelNumber/6+1)*(1+0.25*sin(PI/3)/(1+sin(PI/6)))=(TDCChannelNumber/6+1)*(1.14434);
if the layer number (X) is even then the Y position center needs to be shifted backward in the Y direction by
y[HitNumber]-=sin(PI/3)/(1+sin(PI/6));

The uncertainty in the position is

DeltaX=1/sqrt(12);
DeltaY=sin(PI/3)/(1+sin(PI/6))/sqrt(3);

TDCChannelNumber is used to locate the row and column of the wire that saw an ionization signal.

Layer(X)    Wire(Y)      Time
3(3)    6(7.26221)    1415
1(1)    6(7.26221)    1368
6(6)    6(6.42074)    1308
4(4)    6(6.42074)    1311
2(2)    6(6.42074)    1332
5(5)    7(8.47257)    1419


A linear fit is performed assuming that the ionization event occurs in the center of the cell. Later a drift time function should be used to offset each hit from the center according to the drift time function that uses the TDC measurement as an input.

Below is the incident cosmic ray angle when only 6 hits occur in the chamber for run CLAS12_r4135